SCS Book 1 Preview by MI Student Resources

Fishing Master Program Ship Construction and Stability Book 1 Version 1.0

Except as provided by legislation governing the use of materials for educational purposes, no part of this publication may be reproduced, stored in a database or a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior written permission from the Marine Institute of Memorial University. Care has been taken to ensure that ownership of any copyright material contained in this publication is being traced and permission for its use obtained. The Marine institute would welcome any information that would correct any errors or omissions in assigning appropriate credit or reference in future editions.

Table of Contents

Table of Contents Introduction · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · i-3 Outline · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · O-3 Chapter 1 Basic Ship Measurement and Design Terminology · · · · · · · · · · · · · · · · · · · · · · · · · 1-3 1.1

Basic Dimension Terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-3

1.2 Vessel structural stresses · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-10 1.3 Hull description terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-12 1.4 Tonnage descriptions · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-14

Chapter 2 Hull Shapes and Structural Terminology · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-3 2.1

Overview of Current domestic fleet structure· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-3

2.2 Ship’s plans· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-4 2.3 Ship’s area and volume terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-6 2.4 Hull shape terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-8 2.5 Hull Integrity Terminology · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-9 2.6 Structural members and parts of fishing vessels· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-10 2.7 Construction Techniques· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-18

Chapter 3 Vessel Seaworthiness and Regulatory Requirements · · · · · · · · · · · · · · · · · · · · · · · 3-3 3.1 A vessel’s sea keeping characteristics · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 3-3 3.2 The importance of maintaining watertight integrity · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 3-4 3.3 Freeing Ports· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 3-8 3.4 Particular watertight measures aboard fishing vessels· · · · · · · · · · · · · · · · · · · · · · · · · · · 3-10 3.5 Damage Control Techniques· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 3-18 3.6 Concepts of Bilging and Permeability · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 3-19

Chapter 4 Essential Vessel Systems and Inspection Protocol· · · · · · · · · · · · · · · · · · · · · · · · · · 4-3 4.1 Bilge, Fire and Ballast Pumping Arrangements· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 4-3 4.2 Electrical Systems · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 4-8 4.3 On board alarm systems· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 4-10 4.4 Protection against fire· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 4-11 4.5 Transport Canada Inspection Regime and standard self-inspection practices · · · · · · · · 4-13

Fishing Master Program, Ship Construction and Stability Book I

Table of Contents

Chapter 5 Basic Ship Stability Terminology · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 5-3 5.1 Principles of flotation · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 5-3 5.2 Angles of incline · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 5-4 5.3 General Stability terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 5-6

Chapter 6 Basic Transverse Stability Principles · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6-3 6.1

Initial Stability Terminology· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6-3

6.2 Transverse Stability Principles· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6-13

Chapter 7 Interpreting Righting Curves· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 7-3 7.1 Factors Affecting a Vessel’s Righting Energy· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 7-3 7.2 Comparison of typical 65’ vessels and their pre-departure GZ curves· · · · · · · · · · · · · · · 7-15 7.3

Stab 4 criteria· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 7-22

7.4 Initial vs. Overall Stability - The Hidden Danger · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 7-23

Chapter 8 Basic Longitudinal Stability Principles· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-3 8.1 Comparison of Longitudinal to Transverse Stability · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-3 8.2 Directional Stability· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-7 8.3

Tonnes per Centimeter Immersion (TPC) / Tonnes per Inch Immersion (TPI)· · · · · · · · · · · 8-8

8.4 Water Density and Fresh Water Allowance · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-11 8.5 Load Lines (Minimum Freeboard)· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-12 8.6 Moment to Change Trim 1 Centimeter (MCTC)· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-14 8.7

Dry docking· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8-16

Chapter 9 Principles of Free Surface Effect, Freeboard and Reserve Buoyancy· · · · · · · · · · · 9-3 9.1 The Dangers of Free Surface Effect· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 9-3 9.2 The Free Surface Formula· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 9-9 9.3 Free Surface associated with vessel stabilizing system· · · · · · · · · · · · · · · · · · · · · · · · · · · 9-12 9.4 Freeboard and Reserve Buoyancy · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 9-13 9.5 Initial vs. Overall Stability - The Hidden Danger of Improper Ballasting · · · · · · · · · · · · · 9-19

Chapter 10 Anti-Roll Devices and Vessel Stability· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 10-3 10.1 Paravane Stabilizer System· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 10-3 10.2 Anti-roll Tank (ART) Stabilizing Systems· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 10-8 10.3 Principle of Anti-roll Shocks · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 10-13

Table of Contents

Chapter 11 Vessel Modifications and Its Effect on Stability · · · · · · · · · · · · · · · · · · · · · · · · · · 11-3 11.1 Modifications Associated with Re-fitting for Different Fisheries · · · · · · · · · · · · · · · · · · · 11-3 11.2 Hull or Deckhouse Structural Alterations or Modifications· · · · · · · · · · · · · · · · · · · · · · · · 11-3 11.3 Bow Thrusters · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 11-8 11.4 Kort (Rice) Nozzles (shrouded propellors) · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 11-10

Chapter 12 Interpreting Stability Booklet Data· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-3 12.1 Transport Canada Approval Process · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-3 12.2 Stability Booklet Information · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-5 12.3 Current Condition vs. Pre-Calculated Condition· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-25 12.4 Taking Corrective Action· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-28 12.5 Ullage Tables· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 12-28

Chapter 13 Effect of Fishing Operations on Vessel Stability· · · · · · · · · · · · · · · · · · · · · · · · · · 13-3 13.1 The Effect of Handling Fishing Gear on Stability· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 13-3 13.2 Change of Stability During Voyage· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 13-10 13.3 Dangers Associated with the Improper Stowage of Fish · · · · · · · · · · · · · · · · · · · · · · · · 13-10 13.4 Shock Loads on Gear· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 13-13

Chapter 14 Environmental Effects on Stability - The Dynamics· · · · · · · · · · · · · · · · · · · · · · · · 14-3 14.1 Stability Warning Signs and Precautions - Summary and Review · · · · · · · · · · · · · · · · · · · 14-3 14.2 The Effects of Sea Conditions on Stability· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-4 14.3 Dangers associated with following seas· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-8 14.4 Beam Seas· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-11 14.5 Quartering Seas· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-12 14.6 Winds on the Beam· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-12 14.7 Icing· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 14-14

Index

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · I-3

Fishing Master Program, Ship Construction and Stability Book I

Table of Contents

ÂŠ Marine Institute of Memorial University

Introduction

Unfortunately in recent years the fishing industry in Canada in general has witnessed too many tragic losses. Fish harvesters are forced by economic realities to fish further and further from land, endure more adverse weather and to use vessels and technology that has become more and more sophisticated. DFO statistics for the year 2010 show that there are some 17,207 commercial fishing vessels registered in Atlantic Canada alone with well over 20,000 registered in all of Canada. { Source: http://www.dfo-mpo.gc.ca/stats/commercial/licences-permis/pacific-pacifique/pacfleet-eng.htm } According to a Transportation Safety Board of Canada report that was released in the summer of 2013, during the period from 1999 to 2010, some 2514 fishing related accidents were reported in Canada. Of these 112 were fatal, resulting in 154 deaths. The report also found that 89 deaths or 58% actually happened due to a stability-related accident such as capsizing, foundering, flooding or sinking. { Source: http://www.tsb.gc.ca/eng/rapports-reports/marine/etudes-studies/m09z0001/m09z0001.pdf } These statistics reinforce the importance of understanding at least the basics of stability. Simply stated, ship stability refers to its ability to return to its initial position after being inclined by an external force. In essence, the study of statical stability deals with the 'static condition' of a vessel under a given circumstance, whereas the term 'dynamical stability' deals with the work involved, or measure of the external force, which inclines a vessel. In simple terms, a vessel must have adequate statical stability at a given time to allow for the dynamical requirements imposed upon it by the environment in which it operates, otherwise it will capsize. This course begins by introducing participants to basic terminology and principles as they apply to ship construction and fundamental stability theory as outlined in Transport Canada publication TP 2293E section 24.5, examination code SCS 1. In latter modules, it then examines the additional requirements as outlined in section 23.7 of the same TP, examination code SCS 2. { Source: http://www.tc.gc.ca/eng/marinesafety/tp-tp2293-menu-2254.htm }

Used in conjunction with the on line Fishing Vessel Stability E Simulator, as referenced appropriately throughout the manual, the participant has all the tools necessary to gain an indepth knowledge of fishing vessel stability from both a theoretical and practical perspective. While not an essential component to the successful completion of either SCS 1 or SCS 2, for those who wish to use it, the stability e Simulator will provide that added reinforcement to aid in the understanding of many concepts. To successfully challenge the appropriate stability and construction exam as required for the Fishing Master 4 or 3 program a good working knowledge of a fishing vessel stability booklet is required. The metric version of the stability booklet for the fishing vessel â&#x20AC;&#x2DC;Skateâ&#x20AC;&#x2122;, as is used in both SCS1 and SCS2 exams will be referenced throughout this course. It is important that the participant follow through and thoroughly familiarize themselves with this booklet. To further aid in the understanding of the theory and concepts discussed as well as the required calculations for the SCS 2 material, a student workbook has been compiled to be completed parallel with this manual. Standard stability theory and methodology has not changed significantly for some time. As mariners it is vital that we learn stability in the traditional manner, by first familiarizing ourselves with the basic language and vocabulary used and then linking the knowledge of all this new terminology with standard stability concepts. The real challenge then lies in applying this new information, which by its very nature is a somewhat 'dry' technical subject, to practical real life decision making. The ultimate goal of this course is for the participant to have gained an adequate understanding of the connection between a vessel's design (construction) and basic

Fishing Master Program, Ship Construction and Stability Book I

iii

Introduction

stability theory so that well informed decisions will be made based on a good understanding of their possible consequences while at the same time respecting good seamanship practices. To accomplish this objective it is absolutely necessary to study a very wide range of topics and to look rather closely at certain stability concepts from a practical point of view. Fishing Vessel Stability Simulator (FVSS): Before you begin with Module 1, if you have access to a computer, please follow the following link and download the Fishing Vessel Stability E Simulator to your computer, free of cost, from the Canadian Council of Professional Fish Harvesters web site: http://www.fishharvesterspecheurs.ca/professional-development/safety/stability-simulator

Course List of Resources • Instructors manual • Participants manuals • CD with Power Point Presentation for course • Hard copy collection of all powerpoints for reference. • Set of stability wall charts (white board markers and eraser) • Set of TSB Reports on fishing vessel capsizings and applicable Transport Canada Ship Safety Bulletins • F/V 'Skate' stability booklet (Metric version) • Instructors reference text books:

– Ship Stability for Masters and Mates, C.B.Barrass and D.R.Derrett

– Simple Ship Stability, A guide for seafarers and fishermen, Alfred Carver - Stability and Trim of Fishing Vessels, J.Anthony Hind

– Ship Stability, Notes and Examples, (Kemp and Young), Dr.C.B. Barrass

• Participants text books: (one per participant)

– Stability and Trim of Fishing vessels, J.Anthony Hind

• Course evaluation forms for participants • Course evaluation forms for Instructor • Registration forms, material checklists and other administrative material

Course Delivery – Helpful Hints • By its nature the study of stability and naval architecture involves substantial math and calculation. This course is designed to present stability in an unconventional manner. Try to point out the practical application of each topic throughout the course. Encourage participants’ involvement by relating the theory to real life circumstances. iv

Introduction

• When discussing the TSB reports be sure to bear in mind that these are real life tragedies and we never know the background connection of all participants. Impress upon them the sensitivity of this information and the importance that we study them to learn from the past misfortunes of our colleagues, not to assign blame or criticize. • Encourage participants to bring in their own stability booklets and help them to interpret the information. All stability booklets are laid out similarly and it would foster greater interest in the material. • Valid arguments against pushback to learning stability would be:

– Simply point out the substantial validity of a FM4 Certificate

– The virtues of professionalism. We would expect nothing less from other professionals such as a mechanic, electrician or computer repair shop. With professionalism comes responsibility to keep abreast of developments in ones chosen profession.

– Example: If we put our car in the garage for repair, we each expect and demand that the technician has a responsibility and duty to know his/her job because our safety and that of our family when driving down the highway depends on it. Its not adequate for them to only know where the repair manual is kept, they must be able to use its contents to properly execute their job. Stability booklets are of similar importance, probably more so! Many other examples can be used in this regard.

• Better education and awareness helps to circumvent excessive and expensive regulation. Note: It would be a good idea for each student to create their own list of stability abbreviations and formula as they work through the course.

Fishing Master Program, Ship Construction and Stability Book I

Introduction

ÂŠ Marine Institute of Memorial University

Outline

Introduction to Construction and Stability for Fishing Vessels

Type and Purpose: Fishing vessel construction and stability are important, interconnected areas of study to ensure the safe operation and handling of fishing vessels. It is essential that vessel operators have a good understanding of the relationships that exist between the vessels shape, builderâ&#x20AC;&#x2122;s plans and how a completed hull operates in a marine environment. This course is specifically directed towards fishing vessel operators and deals with the basic theory and application of construction and stability as it applies to fishing vessels in various conditions of load.

Calendar Entry: Basic Ship Measurement and Design Terminology; Hull Shapes and Structural Terminology; Vessel Seaworthiness and Regulatory Requirements; Essential Vessel Systems and Inspection Protocol; Basic Ship Stability Terminology; Basic Transverse Stability Principles; Interpreting Righting Lever Curves; Basic Longitudinal Stability Principles; Principles of Free Surface Effect, Freeboard and Reserve Buoyancy; Anti Roll Devices and Vessel Stability; Vessel Modifications and Its Effect on Stability; Interpreting Stability Booklet Data; Effect of Fishing Operations on Vessel Stability; Environmental Effects on Stability â&#x20AC;&#x201C; The Dynamics

Duration: As required

Course Aims: 1. To gain a basic understanding of the principles on which fishing vessel stability is based. 2. To gain introductory knowledge that allows for the safe operation of fishing vessels under various conditions of load. 3. To become familiar with the tools necessary for the safe operation of a fishing vessel. 4. To be able to comprehend the basics of fishing vessel stability booklets for the safe operation of a fishing vessel. 5. To understand the various methods of employing stability criteria. 6. To gain an appreciation for vessel construction and alteration and how it relates to operational safety.

Evaluation: Transport Canada exams SCS I and SCS II

Fishing Master Program, Ship Construction and Stability Book I

O-3

Outline

Major Topics 1.0

Basic Ship Measurement and Design Terminology

2.0

Hull Shapes and Structural Terminology

3.0

Vessel Seaworthiness and Regulatory Requirements

4.0

Essential Vessel Systems and Inspection Protocol

5.0

Basic Ship Stability Terminology

6.0

Basic Transverse Stability Principles

7.0

Interpreting Righting Lever Curves

8.0

Basic Longitudinal Stability Principles

9.0

Principles of Free Surface Effect, Freeboard and Reserve Buoyancy

10.0 Anti Roll Devices and Vessel Stability 11.0 Vessel Modifications and Its Effect on Stability 12.0 Interpreting Stability Booklet Data 13.0 Effect of Fishing Operations on Vessel Stability 14.0 Environmental Effects on Stability - The Dynamics

Course Outline 1.0 Basic Ship Measurement and Design Terminology 1.1

Basic Dimension Terminology

1.2

Vessel Structural Stresses

1.3

Hull Description Terminology

1.4

Tonnage Descriptions

2.0 Hull Shapes and Structural Terminology

O-4

2.1

Overview of Current Domestic Fleet Structure

2.2

Ship’s Plans

2.3

Ship’s Area and Volume Terminology

2.4

Hull Shape Terminology

2.5

Hull Integrity Terminology

Outline

2.6

Structural Members and Parts of Fishing Vessels

2.7

Construction Techniques

3.0 Vessel Seaworthiness and Regulatory Requirements 3.1

A Vessel’s Sea Keeping Characteristics

3.2

Maintaining Water Tight Integrity

3.3

Freeing Ports

3.4

Particular Watertight Measures Aboard Fishing Vessels

3.5

Damage Control Techniques

3.6

Bilging and Permeability

4.0 Essential Vessel Systems and Inspection Protocol 4.1

Bilge, Fire and Ballast Pumping Arrangements

4.2

Electrical Systems

4.3

Onboard Alarm Systems

4.4

Protection Against Fire

4.5

Transport Canada Inspection Regime and Standard Self-inspection Practices

5.0 Basic Ship Stability Terminology 5.1

Principles of Flotation

5.2

Angles of Incline

5.3

General Stability Terminology

6.0 Basic Transverse Stability Principles

7.0

6.1

Initial Stability Terminology

6.2

Transverse Stability Principles

Interpreting Righting Lever Curves 7.1

Factors Affecting a Vessel’s Righting Energy

7.2

Comparison of Typical <65’ Vessels and Their Pre-departure GZ Curves

7.3

Stab 4 Criteria

7.4

Initial vs. Overall Stability - The Hidden Danger

Fishing Master Program, Ship Construction and Stability Book I

O-5

Outline

8.0 Basic Longitudinal Stability Principles

9.0

8.1

Comparison of Longitudinal to Transverse Stability

8.2

Directional Stability

8.3

Tonnes Per Centimeter (TPC) and Tonnes Per Inch (TPI) Immersion

8.4

Water Density and Fresh Water Allowance

8.5

Load Lines (Minimum Freeboard)

8.6

Moment to Change Trim One Centimeter (MCTC)

8.7

Effect of Dry-docking on Stability

Principles of Free Surface Effect, Freeboard and Reserve Buoyancy 9.1

The Dangers of Free Surface Effect

9.2

Calculating Free Surface by Formula

9.3

Free Surface Associated with Vessel Stabilizing System

9.4

Freeboard and Reserve Buoyancy

9.5

Initial vs. Overall Stability â&#x20AC;&#x201C; The Hidden Danger of Improper Ballasting

10.0 Anti Roll Devices and Vessel Stability 10.1

Paravane Stabilizer System

10.2

Anti-roll Tank Stabilizing Systems (ART)

10.3

Principle of Anti-roll Shocks

11.0 Vessel Modifications and Its Effect on Stability 11.1

Modification Associated with Re-fitting for Different Fisheries

11.2 Hull or Deckhouse Structural Alterations or Modifications 11.3

Bow Thrusters

11.4 Kort (Rice) Nozzles

12.0 Interpreting Stability Booklet Data 12.1 Transport Canada Approval Process 12.2 Stability Booklet Information 12.3

Current Condition vs. Pre-calculated Condition

12.4 Taking Corrective Action O-6

ÂŠ Marine Institute of Memorial University

Outline

12.5

Ullage Tables

13.0 Effect of Fishing Operations on Vessel Stability 13.1 The Effect of Handling Fishing Gear on Stability 13.2 Change of Stability During the Voyage 13.3 Dangers Associated With the Improper Stowage of Fish 13.4 Shock Loads On Gear

14.0 Environmental Effects on Stability – The Dynamics 14.1 Stability Warning Signs and Precautions - Summary and Review 14.2 The Effects of Sea Conditions on Stability - ‘The Dynamics’ 14.3 Following Seas 14.4 Beam Seas 14.5

Quartering Seas

14.6 Winds on the Beam 14.7 Icing

Learning Objectives At the end of this course, the learner will be able to:

1.0

Basic Ship Measurement and Design Terminology 1.1

Basic Dimension Terminology

– Define the following terms:

• Baseline

• Longitudinal

• Transverse

• Breadth

• Depth

• Freeboard

– Discuss ship length terminology.

– Discuss draft and draft marks.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

1.2

Vessel Structural Stresses

– Explain hogging. – Explain sagging.

– Discuss racking stresses.

– Define “panting” and “pounding stresses.”

– Define the term “scantlings”.

1.3

– Define the following terms:

• Sheer

• Camber

• Flare

• Entrance, run, and parallel middle body

• Tumblehome

• Deadrise

1.4

2.0

Hull Description Terminology

Tonnage Descriptions

– Define the following terms:

• Gross tonnage

• Net tonnage

• Displacement tonnage

• Deadweight tonnage

Hull Shapes and Structural Terminology 2.1 Overview of Current Domestic Fleet Structure – Discuss fleet structural changes in recent years. 2.2

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Ship’s Plans

– Identify different ship’s plan views.

– Explain different datum lines.

– Explain how waterlines appear on different plan views.

– Explain how buttock lines appear on different plan views.

– Describe how body section lines appear on plans.

– Discuss what is found in a table of offsets. © Marine Institute of Memorial University

Outline

2.3 Ship’s Area and Volume Terminology – Describe the term “waterplane area.” – Discuss coefficients of Hull Forms. 2.4

Hull Shape Terminology

– Define “round bilge.”

– Define “hard chine.”

– Describe double and multi chine hull forms.

– Describe multi hulled craft.

2.5

Hull Integrity Terminology – Define the following terms:

• Closed construction

• Open construction

• Watertight

• Weathertight

2.6

Structural Members and Parts of Fishing Vessels

2.7

Construction Techniques

3.0

– Identify various equipment and parts of a fishing vessel.

– Discuss construction techniques for wooden fishing vessels. – Discuss construction techniques for steel fishing vessels. – Discuss construction techniques for aluminum fishing vessels. – Discuss construction techniques for fiberglass fishing vessels.

Vessel Seaworthiness and Regulatory Requirements 3.1 A Vessel’s Sea Keeping Characteristics – Define “seakindliness.” – Define “seaworthiness.” 3.2

Maintaining Water Tight Integrity

– Discuss watertight integrity measures aboard fishing vessels.

– Demonstrate the ability to find fishing vessel construction standards.

– Demonstrate an awareness of Transport Canada’s regulatory requirements for watertightness / weathertightness aboard fishing vessels.

3.3

Freeing Ports

– Explain the importance of maintaining adequate freeing ports.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

3.4

Particular Watertight Measures Aboard Fishing Vessels

– Discuss the watertightness of doors, windows, portholes, and other access openings.

– Discuss the watertight integrity of propulsion shafting, thrusters and sounding devices.

– Describe how thru-hull fittings and valves maintain watertightness.

– Discuss the function of bulkheads and subdivisions.

3.5

Damage Control Techniques

3.6

Outline emergency procedures to control flooding due to damage.

Bilging and Permeability

4.0

–

Discuss the practical considerations of bilging and permeability.

Essential Vessel Systems and Inspection Protocol 4.1 Bilge, Fire and Ballast Pumping Arrangements – Explain the function of pumping arrangements. 4.2

Electrical Systems

– Explain the reason for proper grounding aboard a fishing vessel.

– Discuss the hazards associated with electrical systems on fishing vessels.

4.3

Onboard Alarm Systems

4.4

– Discuss the various onboard alarm systems on fishing vessels.

Protection Against Fire

– Discuss the benefits of quick closing valves on fuel tanks.

– Explain why there are fire dampers on the ventilation systems.

– Discuss benefits and dangers associated with fire extinguishing systems.

4.5

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– Discuss the importance of corrosion and cathode protection.

Transport Canada Inspection Regime and Standard Self-inspectionPractices

– Explain ‘first inspection’ of a fishing vessel (construction and installation).

– Describe annual or quadrennial inspection requirements.

– Define “targeted inspection.”

–

Define “annual self-inspection.”

Outline

5.0

Basic Ship Stability Terminology 5.1

Principles of Flotation

5.2

– Explain Archimede’s Principle.

Angles of Incline

– Define “list.” – Define “heel.” 5.3

General Stability Terminology

– Define the term “centroid.”

– Explain basically how moments and levers affect stability.

– Describe what the center of flotation is.

– Define “trim.”

6.0

– Explain what is meant by “the center of gravity.”

– Explain what is meant by “the center of buoyancy”

– Illustrate how the metacentre is found.

– Define “reserve buoyancy.”

Basic Transverse Stability Principles 6.1

Initial Stability Terminology

– Discuss what is meant by “metacentric height” (GM) in fishing vessels.

– Discuss the terms “stiff” and “tender” ships.

– Explain standard basic stability terminology.

– Describe the inclining experiment.

– Discuss what is meant by a vessels “rolling period.”

– Demonstrate the ability to perform a roll period test to approximate GM.

– Explain the process of determining a vessel’s initial stability (GM) from a roll period test.

6.2

Transverse Stability Principles

– Illustrate why a fishing vessel returns upright when heeled.

– Define what is meant by “positive stability” or “stable equilibrium.”

– Define what is meant by “negative stability” or “unstable equilibrium.”

Fishing Master Program, Ship Construction and Stability Book I

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Outline

7.0

– Define what is meant by “neutral equilibrium.”

– Identify corrective action for unstable and neutral equilibrium.

– Explain what the righting arm – GZ is.

– Explain what the righting arm curve is.

– Define the term “moment of statical stability.”

Interpreting Righting Lever Curves 7.1

Factors Affecting a Vessel's Righting Energy

– Discuss how a vessels design affects its GZ curve.

– Discuss the effect of loading deck weight on GZ curve.

– Explain the effect of suspended weights on the GZ curve.

– Consider the effect of free surface effect on the GZ curve.

– Explain the effect of downflooding on the GZ curve.

– Outline the benefits of reserve buoyancy for righting energy.

– Discuss low freeboard (excessive draft) in relation to the GZ curve.

– Discuss the effects of excessive trim on GZ curve.

– Outline the effect of water on deck and righting energy.

7.2

Comparison of Typical <65' Vessels and Their Pre-departure GZ Curves

– Discuss some typical 65'vessels and their pre-departure GZ curves.

– Discuss a typical 44' 11" vessel and its pre-departure GZ curve.

– Discuss a typical 54' 11" vessel and its pre-departure GZ curve.

– Consider pre-departure curves and stability data for NL 65'steel fishing vessel.

7.3

Stab 4 Criteria (What, exactly, is "stab 4?" Is this a shortened term for something?)

7.4

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– Discuss the minimum/maximum requirements as per Stab 4.

Initial vs. Overall Stability - The Hidden Danger

– Discuss what is meant by initial stability.

– Discuss what encompasses overall stability.

– Relate initial vs. overall stability in relation to overloading.

– Discuss initial vs. overall stability with regard to improper ballasting.

Outline

(This also appears as a subtopic (9.5) below. Should this objective be placed with that subtopic?)

8.0

– Discuss initial vs. overall stability and the dangers of weight creep.

Basic Longitudinal Stability Principles 8.1

Comparison of Longitudinal to Transverse Stability

8.2

Directional Stability

8.3

– Demonstrate an understanding of the concept of directional stability. (How?)

Tonnes Per Centimeter (TPC) and Tonnes Per Inch (TPI) Immersion

8.4

– Discuss similarities and differences between longitudinal and transverse stability.

– Demonstrate a practical understanding of the concepts of TPC and TPI. (How?)

Water Density and Fresh Water Allowance

– Discuss the effect of water density on ship's draft.

– Shouldn't there be an objective that refers to "fresh water allowance?"

8.5

Load Lines (Minimum Freeboard)

– Discuss merchant vessel load lines.

– Provide a brief description of merchant vessel load lines.

– Discuss their history. (There were three objectives in the one, so I broke them out.)

8.6

Moment to Change Trim One Centimeter (MCTC) - Define the term "MCTC."

8.7

Effect of Dry-docking on Stability

– Explain the effects of dry-docking on vessel's stability.

9.0 Principles of Free Surface Effect, Freeboard and Reserve Buoyancy 9.1

The Dangers of Free Surface Effect

– Define "free surface effect."

– Explain the dangers associated with slack tanks.

– Discuss the dangers associated with cross-connected tanks.

– Discuss the dangers of progressive downflooding.

– Discuss the dangers of water on deck.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

– Discuss the dangers associated with flooded deckhouses.

– Discuss and summarize all of the points raised on free surface. (Need to be more specific, i.e., what points in particular. If you are referring to the ones listed above, perhaps we can change the above objectives to "discuss and summarize...".)

9.2

Calculating Free Surface by Formula

9.3

Free Surface Associated with Vessel Stabilizing System

9.4

– Demonstrate the ability to calculate free surface effect using formula. (Slight rewording from "abilty to calculating free...")

– Discuss free surface effect in relation to an ART or RSW system. (What do ART and RSW stand for?)

Freeboard and Reserve Buoyancy

– Discuss briefly the critical importance of freeing ports.

– Discuss the importance of adequate freeboard and reserve buoyancy.

– Discuss the theory behind deck edge immersion.

– Discuss the practical considerations of deck edge immersion.

9.5

Initial vs. Overall Stability - The Hidden Danger of Improper Ballasting

– Explain the expression "improper ballasting - the myth."

10.0 Anti Roll Devices and Vessel Stability 10.1 Paravane Stabilizer System

– Outline the basic parts of the system and their function. (Need to be more specific, i.e., what "basic parts" in particular.)

– Explain the principle behind their operation.

– Discuss the dangers associated with their use.

10.2

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Anti-roll Tank Stabilizing Systems (ART)

– Discuss the principle behind their operation.

– Discuss the construction and placement of the ART.

– State the advantages of an ART as compared to paravane stabilizers. (Changed "compare" to "state" for better sentence structure.)

– Explain the dangers associated with the use of an ART.

Outline

10.3 Principle of Anti-roll Shocks

– Discuss anti-roll shocks or bilge keels on fishing vessels. (Need to be more specific, i.e., what, exactly, is to be discussed about them...their principles of use?)

11.0 Vessel Modifications and Its Effect on Stability 11.1 Modification Associated with Re-fitting for Different Fisheries

– Discuss stability concerns of refitting a vessel for different fisheries.

11.2 Hull or Deckhouse Structural Alterations or Modifications

–

iscuss the possible stability implications of altering the vessel by way D of increasing vessel beam, length, freeboard and draft.

– Discuss the possible stability implications of adding sponsons and other appendages to a vessel.

– Explain the possible stability implications of glassing over a wooden vessel.

– Discuss the stability implications of going from dry to wet stowage.

– Discuss the advantages and disadvantages of bulbous bows.

11.3 Bow Thrusters

– Discuss the advantages and limitations of bow thrusters.

11.4 Kort (Rice) Nozzles

– Discuss the advantages and disadvantages of kort nozzles.

12.0 Interpreting Stability Booklet Data 12.1 Transport Canada Approval Process

– Discuss the requirements and process to get a stability booklet approved by Transport Canada.

12.2 Stability Booklet Information

– Discuss the importance of the Notes to the Master section.

– Demonstrate an understanding of tank plans and tank status tables. (How?)

–

Interpret tank characteristic tables.

–

Interpret light ship condition information.

– Interpret pre-departure condition information.

– Interpret other conditions contained in the stability booklet.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

– Extract information from hydrostatic tables and curves.

– Discuss cross curves of stability.

– Interpret maximum VCG or KG vs. displacement tables and curves. (Can this objective be worded in a way that makes it a bit clearer? Also, what do VCG and KG stand for?)

12.3 Current Condition vs. Pre-calculated Condition - Construct a displacement table (loading sheet). 12.4 Taking Corrective Action 12.5

– Define correct procedures to prevent or rectify dangerous situations.

Ullage Tables

– Interpret data found in the ullage tables.

13.0 Effect of Fishing Operations on Vessel Stability 13.1 The Effect of Handling Fishing Gear on Stability

– Define and describe "active fishing gear."

– Define and discuss "passive fishing gear."

– Discuss the dangers of shifting loads.

– Explain why lifting weights is hazardous.

– Explain why lifting weights over the side is of particular hazard.

– Discuss the unique stability problems of towing fishing gear.

– Explain the potential problems of towing fishing gear while turning.

13.2 Change of Stability During the Voyage

– Discuss general stability considerations during the voyage.

13.3 Dangers Associated With the Improper Stowage of Fish

– Relate the importance of bulkheads to a fishing vessel.

– Discuss the importance of pen boards. (Sample free surface calculation) (What do you mean by this?)

– Discuss the dangers of fish carried on deck, overloading and excessive trim.

13.4 Shock Loads On Gear

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– Discuss shock loads on fishing gear.

Outline

14.0 Environmental Effects on Stability - The Dynamics 14.1 Stability Warning Signs and Precautions - Summary and Review - Demonstrate an understanding of practical stability precautions as outlined on Transport Canada web site. (How?) 14.2 The Effects of Sea Conditions on Stability - 'The Dynamics' - Describe a vessel's six degrees of motion.

– Understand the dynamic effects on the GZ curve 'reserve righting energy'.

14.3 Following Seas

– Discuss the dangers of following seas - riding down the face of a steep wave.

– Discuss the dangers of following seas - riding on the crest of a steep wave.

– Discuss the dangers of following Seas - riding in the trough of a steep wave.

14.4 Beam Seas

– Discuss the concerns of operating a fishing vessel in beam seas.

14.5 Quartering Seas

– Discuss the concerns of operating in a quartering sea.

14.6 Winds on the Beam

– Describe the stability concerns of operation of a vessel with strong beam winds (heeling force).

14.7 Icing

– Explain the dangers to a vessel's stability in icing conditions.

– Discuss the specific recommendations and proper procedures in icing situations according to Transport Canada Recommendations.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

Syllabuses of Examinations Ship Construction and Stability, Level 1 (Examination Code: SCS 1) 1) The examination consists of multiple-choice questions based on a vessel’s stability data booklet. 2) The examination is of three hours duration. 3) The SCS 2 may be substituted for SCS 1 at the applicant’s request. 4) The examination is based upon: Subject

Knowledge required

Competence

Maintain vessel stability

Understanding stability basic terminology

Terms Meaning of displacement, deadweight, lightship weight, load displacement; Meaning of list, heel, loll; Meaning of gravity, centre of gravity (G), height of centre of gravity above keel/baseline (KG); Meaning of buoyancy, centre of buoyancy (B), reserve buoyancy; Meaning of righting lever (GZ) when the vessel is heeled, metacentre (M), metacentric height (GM) and roll period as an indication of initial stability; Meaning of centre of flotation (F) and trim; Meaning of draft, freeboard, deck edge immersion and downflooding.

Understanding transverse stability principles

Understanding of: Effect of water density on draft and freeboard and Fresh Water Allowance (FWA); Ability to explain using a sketch of a heeled vessel, how the centre of gravity (G) and the centre of buoyancy (B) are acting to create a righting lever (GZ); Effect on stability of adding, removing, transferring and suspending weights; Stable equilibrium, unstable equilibrium, neutral equilibrium; Correcting unstable and neutral equilibrium and angle of loll; Stiff and tender ships; Negative GM and angle of loll; Free surface effect of liquids on stability and the danger of slack tanks; Moment of statical stability; Effects of reduction in freeboard on stability and the dangers of overloading.

Practical use of stability data supplied to fishing vessels

Use of displacement and ton per inch / tonne per centimetre (TPI/TPC) scales to determine displacement from draft and vice versa; Understanding of data found in fishing vessels stability booklets; Use of pre-calculated operating conditions to ascertain adequate stability; Recognize situations where the vessel does not meet the pre-calculated operating conditions and ability to rectify the situation; Identify fish loading limits according to fuel, water, crew and provisions carried; Interpreting curves of statical stability; Effects of reduction in freeboard on stability and the dangers of overloading.

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Outline

Subject

Knowledge required

Competence

Maintain vessel stability

Effect of vessel’s operations including catch handling

Fishing operations The operational difference between active and passive fishing gear; The effect of deploying and embarking fishing gear; The dangerous effect of external forces from fishing gear and other gear when catching obstructions on the sea bed or when gear is acting on a high point in the vessel; Effect of adding, removing, transferring, raising, lowering or suspending weights on draft, list and trim, allowing for the free surface effect of tanks; The change of stability during the voyage. Catch handling and stowage method Strength and purpose of division bulkheads in fish holds; Effect of carrying fish in bulk; Effect of carrying fish in bulk instead of subdivided holds or individual containers; The dangerous effects of carrying fish on deck; Danger of overloading, including excessive trim by the stern; Understanding the use, effect and risks of anti-rolling devices such as: Paravane stabilizers; Anti-rolling tanks

Effect of environmental conditions on vessel’s stability

Understanding the effect of severe wind and rolling in associated sea conditions, especially in following seas; Effect of water on deck including free surface effect; The effect of ice accretion on stability.

Effect of vessels and gear modifications on vessel’s stability

Understanding of how stability is affected by: Gear or fishing gear modifications; Vessel hull or superstructure construction modifications; Holds converted from dry to wet stowage.

Estimating the metacentric height of a vessel and the height of the vessel’s centre of gravity

A general understanding of the methods used to estimate or determine the metacentric height of a vessel (GM) and the height of the vessel’s centre of gravity (KG) by: Inclining test; Rolling test.

Competence

Maintain seaworthiness of the vessel (construction)

Understanding basic construction terminology as it applies to fishing vessels

Terms: Meaning of length overall, length between perpendiculars, breadth, d epth, moulded dimensions, baseline, gross tonnage and net tonnage; Meaning of open and closed construction; Meaning of weathertight and watertight; Identify the principal structural members of a fishing vessel; Identify the proper names of the various parts.

Fishing Master Program, Ship Construction and Stability Book I

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Outline

Subject

Knowledge required

Competence

Maintain seaworthiness of the vessel (construction)

Fishing vessels types and construction methods

Basic knowledge of methods of construction of: Wooden hull vessels; Fibre-reinforced plastic hull vessels; Steel hull vessels; Aluminum hull vessels. Basic knowledge of construction and design variations of: Traps vessels, stern and side trawlers, seine vessels, long line vessels, gill net vessels, dredge fishing vessels, etc.

Maintain integrity of the hull and superstructures and prevent water flooding

Basic knowledge of: How watertight and weatherthight integrity is maintained; Purpose and maintenance of water-freeing arrangements and freeing ports in bulwarks How the minimum size and number of freeing ports required is determined; The construction of doors, door sills, windows, portholes and access openings; The construction of ventilators and air pipes; Cargo and fish hold hatchway closures and fish scuttles covers; Sounding devices; Crew protection by bulwarks, rails and guards; How water ingress is prevented through hull openings (valves) & shaft.

Survivability of the vessel in case of flooding and damage control

Understand the construction and importance of bulkheads as strength members and their watertight integrity to prevent total flooding, in particular the collision bulkhead; The functions and construction of bilge and pump systems and water level detectors. Identify damage control techniques for various flooding scenarios as: Small and large hull breach, damaged through hull fittings, split piping, chafed hose, packing gland, etc.

Protection against fires

The purpose and operation of: Quick closing valves on fuel tanks; Fire dampers on ventilators; Fire extinguishing systems.

Vessel inspection and maintenance

Awareness of the normal maintenance to ensure: Compliance with standards and regulations; Hull, machinery and all equipments remain in good operational order; Corrosion and cathodic protection. Awareness of the Transport Canada Marine Safety inspection regime concerning: Construction and installation inspection, initial inspection, periodic inspection, random inspection, annual self inspection and targeted inspection.

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ÂŠ Marine Institute of Memorial University

Outline

SHIP CONSTRUCTION AND STABILITY, LEVEL 2 (EXAMINATION CODE: SCS 2) 1) The examination consists of multiple-choice questions and practical calculations based on a vesselâ&#x20AC;&#x2122;s stability data booklet. 2) The examination is of a three hours duration. 3) The examination is based upon. Subject

Knowledge required

Competence

Maintain vessel stability

Understanding stability basic terminology

Understanding transverse stability principles

Practical use of stability data supplied to fishing vessels

Fishing Master Program, Ship Construction and Stability Book I

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Outline

Subject

Knowledge required

Competence

Maintain vessel stability

Effect of vessel’s operations including catch handling

Effect of environmental conditions on vessel’s stability

Effect of vessels and gear modifications on vessel’s stability

Understanding of how stability is affected by: Gear or fishing gear modifications; Vessel hull or superstructure construction modifications; Holds converted from dry to wet stowage.

Estimating the metacentric height of a vessel and the height of the vessel’s centre of gravity

A general understanding of the methods used to estimate or determine the metacentric height of a vessel (GM) and the height of the vessel’s centre of gravity (KG) by: Inclining test; Rolling test.

Competence

Maintain seaworthiness of the vessel (construction)

Understanding basic construction terminology as it applies to fishing vessels

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Outline

Subject

Knowledge required

Competence

Maintain seaworthiness of the vessel (construction)

Fishing vessels types and construction methods

Maintain integrity of the hull and superstructures and prevent water flooding

Survivability of the vessel in case of flooding and damage control

Protection against fires

The purpose and operation of: Quick closing valves on fuel tanks; Fire dampers on ventilators; Fire extinguishing systems.

Vessel inspection and maintenance

Fishing Master Program, Ship Construction and Stability Book I

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Outline

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ÂŠ Marine Institute of Memorial University

Chapter 1 Basic Ship Measurement and Design Terminology

Chapter 1 | Basic Ship Measurement and Design Terminology

1.1 Basic Dimension Terminology 1.1.1 Baseline Traditionally the baseline on a ships plan is drawn at the top of the keel plate, parallel to the keel, with all vertical measurements referenced to it. Most fishing vessels are designed with considerable longitudinal trim in all operating conditions. Due to this large ‘rake of keel’, the baseline in many fishing vessel stability booklets is shown to intersect the keel at midships and is placed parallel with one of the vessels load waterlines.

1.1.2 Length The number of ways used to express the length of a vessel might at times be confusing. It is made more so by various agencies using their own definition of length for special purposes. At this stage however, length may be defined as follows:

L.O.A. • Overall length of the vessel.

L.O.A. (length over all) As the name implies, L.O.A. is the distance from the extreme fore part of the vessel to the extreme after part. This length is important when docking is considered, amongst other things. In Canada length over all may be used by ships registry to register a vessel if it is 12 meters or less in length and meets certain other criteria as outlined by Ships Registry. (http://www.tc.gc.ca/MarineSafety/menu.htm )

F/V ‘Skate’ Note the placement of the baseline for fishing vessel ‘Skate’, on page 6 of its stability booklet.

Figure 1.1.2 Basic Dimension Terminology

Fishing Master Program, Ship Construction and Stability Book I

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Chapter 1 | Basic Ship Measurement and Design Terminology

Midships: For practical purposes the term midships refers to the midway point on board a vessel based on its length overall. It is important to note however that within many fishing vessel stability booklets the term midships refers to the middle of the distance between the aft and forward perpendiculars.

The Centerline The longitudinal vertical center plane running from aft to forward is referred to as the ships centerline. Various measurements are referenced as either port or starboard of the centerline in a vessels stability booklet.

L.B.P. (length between perpendiculars) Where the designed load waterline crosses the stem, a perpendicular line is erected known as the forward perpendicular (F.P.). At the after end of the rudder stock another perpendicular line carries the name, after perpendicular (A.P.). The distance between these two perpendicular lines is known as the length between perpendiculars. Amidships is the point midway between the F.P and A.P.

L.B.P. â&#x20AC;˘ Distance between AP and FP.

When a small fishing vessel is registered in Canada generally the length specified on the ships registry is that which is derived from a line drawn at the main deck level parallel to the waterline and which originated and ends at perpendiculars erected where this line passes through the hull structure at the forward end of the vessel and a perpendicular drawn through the center of the rudder stock. This is sometimes referred to at the LBP within the context of the guidelines for the registry of Canadian fishing vessels. (http://www.tc.gc.ca/MarineSafety/TP/Tp13414/menu. htm) See Figure 1.1.2.

L.W.L. (load water line) The LWL is often referred to as simply the waterline length but correctly it is the length on the designed load waterline of the vessel. This length is often used when discussing speed potential and powering of smaller vessels as speed is directly related to waterline length. See Figure 1.1.2. Please note that the centerline is highlighted as a blue line in 4-069 but not specifically referenced in this particular section.

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L.W.L. â&#x20AC;˘ Length of the designed load waterline.

FVSS Sections 4-065 to 4-069

ÂŠ Marine Institute of Memorial University

Chapter 1 | Basic Ship Measurement and Design Terminology

1.1.3 Longitudinal and Transverse The terms longitudinal and transverse are used extensively when discussing ship construction and stability.

Longitudinal Within this context longitudinal refers to lengths in the forward and aft direction as well as structural parts running fwd and aft such as bulkheads, framing, stiffeners and other members. Certain ship stresses are often referred to as longitudinal.

Transverse This refers to the athwart-ships direction across the breadth of a ship (i.e. at right angles to the vessels centreline). Any structural member that runs in this direction is referred to as transverse (i.e. transverse deck beam, transverse floor).

Figure 1.1.3 Logitudinal and Transverse

Fishing Master Program, Ship Construction and Stability Book I

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.1.4 Breadth The moulded breadth (b.mld.) is usually used when referring to metal hulled vessels and is the widest breadth of a vessel measured to the inside of the shell plating. The extreme beam is the maximum breadth taken over all extremities. The difference between the moulded breadth and the extreme breadth is the thickness of the shell plating. When referring to wooden vessels the moulded breadth includes the planking but not any fiberglass coating on the hull.

Breadth â&#x20AC;˘ E xpressed as either moulded breadth or extreme breadth. â&#x20AC;˘ Difference between extreme breadth and moulded breadth is the thickness of the shell plating

Figure 1.1.4 Breadth

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ÂŠ Marine Institute of Memorial University

Chapter 1 | Basic Ship Measurement and Design Terminology

1.1.5 Depth Moulded depth is measured from the top of the keel structure to the top of the deck beam at the side of the vessel amidships. The ‘Camber’ of the deck is generally not included in moulded depth measurements. See Figure 1.1.5. Note: All of the above diagrams were taken from the Transport Canada web site at: http://www.tc.gc.ca/MarineSafety/TP/Tp13430/ forward.htm

Moulded Depth • From the top of the keel structure to the top of the deck beam at the side. • Camber not included.

Figure 1.1.5 Moulded Depth

Fishing Master Program, Ship Construction and Stability Book I

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.1.6 Draft Draft is the vertical distance measured from the underside of the keel to the waterline. Draft can be expressed in either imperial measurement (feet and inches) or using metric measurement (meters and decimeters). Under Canadian regulation the stability booklet of small fishing vessels (<150 T) must be in the same units as the draft marks on that particular vessel. On large fishing vessels (>150 T) metric is used. Generally most people will find metric much easier to work with when doing stability calculations due to its uniform divisibility, however some fish harvesters still prefer to use imperial units.

Draft • The vertical distance measured from the underside of the keel to the waterline. • Mean draft for simplicity is the draft aft + draft forward divided by 2. • The draft denoted by the applicable draft mark is in reference to the bottom of the mark.

Forward Draft & After Draft

The drafts read from the draft marks forward and aft are referred to as the forward draft and the after draft respectively. If a set of draft marks are provided amidships, then the ‘amidships’ draft can be read from those marks. The draft marks forward and aft are usually marked at the forward and after perpendiculars. When this is not possible due to the shape of the hull, then the drafts read from the marks may need correcting to give the drafts at the perpendiculars. The Canada Shipping Act contains detailed information on how draft marks are to be shown (www.tc.gc.ca/acts-regulations/general/C/ csa2001/menu.htm). Briefly, marks must be made so as to be permanent, (i.e. cut in and painted), the marks must be a dark color on a light background or a light color on a dark background, the marks may be in Roman or Arabic numerals and may show the drafts in metric or imperial units, as stated above.

F/V ‘Skate’ Note the draft information as listed in each condition of load in the stability booklet. For the Condition #1, Lightship condition the draft is 2.819 m fwd and 3.579m aft.

Mean draft is the average of the draft forward and draft aft. For practical use on small fishing vessels, this calculation of mean draft is adequate, but it is important to note that in fact a vessel’s true mean draft is located at the center of flotation. We will discuss later why the center of flotation actually moves as the vessel sits at different drafts so therefore the only time that this statement is factually correct is when the longitudinal center of flotation is at amidships. More detail of the theory behind this can be gleaned from stability books such as, ‘Ship Stability for Masters and Mates’, C.B.Barass & D.R. Derrett. For practical purposes we calculate mean draft by: Mean Draft

Fwd draft + Aft draft = 2

Example 1 Forward 6.25m, after draft 6.85m Mean Draft

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6.25 + 6.85 = 2

= 6.55m

Chapter 1 | Basic Ship Measurement and Design Terminology

The mean draft found by the above expression is properly called the “arithmetic” mean draft. When the vessel is listed, the port and starboard drafts must also be averaged to get the mean. The mean draft obviously would be the draft which would be shown by draft marks marked amidships, provided the vessel is neither hogged nor sagged. When marked in imperial units the whole feet are marked and the numeral denoting the number of feet of draft is made six inches in height. The space between numerals is thus six inches also. The draft denoted by the numeral is indicated by the position of the bottom of the numeral. When marked in metric units, the scale may be in decimeters only, at two decimeter intervals, or in meters and decimeters. In the case of a scale marked in meters and decimeters: i. The figures are placed at each meter interval and at intervening two decimeter intervals; ii. The letter “m” is placed after each meter figure; and iii. The top figure of the scale, except where it marks a full meter interval, shows both the meter and decimeter interval. In both types of scale: i. The lower line of each figure, or each figure and letter, coincides with the draft line to which it relates; and ii. Every figure measures one decimeter in height.

Figure 1.1.6 (A) Draft - Imperial Numerals

Figure 1.1.6 (B) Draft – Metric Numerals

FVSS Sections 1-021 to 1-022

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1.1.7 Freeboard Freeboard is the vertical distance from the waterline to the deck at any given point on the vessel. In general the term freeboard is used to identify the point of least freeboard on the vessel.

1.2 Vessel structural stresses

Freeboard • Distance from the water to the deck at a given point. • Usually refers to a vessels least freeboard.

1.2.1 Hogging Hogging is the term used to describe the bending of a ship in the longitudinal plane, when the ends tend to drop relative to amidships.

Figure 1.2.1 Hogging - Sketch showing stresses of hogging and sagging. Sketch reconstructed from ‘Ship Construction sketches and notes’ by Kemp and Young

1.2.2 Sagging Sagging is the term used to describe the bending of the ship in the longitudinal plane, when the amidships section drops relative to the ends. Both conditions can be the result of poor weight distribution in the vessel

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.2.3 Racking These are stresses associated with the transverse deformation of the ship as she rolls in a seaway. The deck tends to move laterally relative to the bottom structure and the shell on one side to move vertically relative to the other. (Ship Construction, author D.J. Eyres)

1.2.4 Panting and Pounding stresses Panting refers to a tendency for the shell plating to work ‘in and out’ in a bellows-like fashion, and is caused by the fluctuating Figure 1.2.3 Racking Stress. Taken from the book, "Ship Dynamics for Mariners',....I.C. Clark BSc, pressures on the hull at the ends when the ship MSc, MNI is amongst waves. This stress is most severe at the bow when the vessel is headed into waves and is pitching heavily. The smaller the deadrise angle the more the vessel is prone to slamming, or in other Structural words if a vessel is ‘fine’ lined forward it will not slam or pound as Stresses much. Pounding (slamming) is severe local stress which occurs in way of the bottom shell and framing forward when a vessel is driven into head seas. Pounding produces considerable stress onto a vessel’s structure. Structural members are usually increased in size and frequency to allow for these stresses.

• Hogging • Sagging • Racking • Panting • Pounding (slamming)

Figure 1.2.4 Panting and Pounding Stress. Taken from the book, "Ship Dynamics for Mariners',....I.C. Clark BSc, MSc, MNI.

1.2.5 Scantlings This is the term used to describe all structural dimensions in ships construction.

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.3 Hull description terminology 1.3.1 Sheer Longitudinal curvature of a vessel’s deck is known as sheer. A well designed sheer line enhances a vessel’s looks but can also be practical ensuring good freeboard forward and aft with low freeboard near amidships. Some vessels have a straight sheer line while small special purpose vessels may have reverse sheer. Sheer forward is often twice as much as sheer aft. The uppermost streak of shell plating on a steel vessel is referred to as the sheer streak as is the uppermost streak of planking on a wooden vessel.

Sheer •L ongitudinal curvature of a ships deck. • O ften ensures good freeboard forward and aft. • Improves overall aesthetics. • Adds strength to the deck.

Figure 1.3.1 outlines sheer and camber. Sketch taken from "Ship Construction" by D.i Eyres p. 12.

1.3.2 Camber Camber refers to the transverse curvature of the weather decks. It enables a vessel to shed water that may otherwise accumulate on the deck. Camber also adds strength to the deck.

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.3.3 Flare The outward curvature of a vessel’s sides near the bow is called flare. As a vessel pitches and the bow is driven deeply into the water, flare provides additional buoyancy to help prevent the bow from driving right under. Flare also directs spray away from the sides of a ship, helping to keep the decks dry.

1.3.4 Entrance, Run, Parallel Middle Body Figure 1.3.3 Tumblehome

The entrance is the underwater part of a vessel’s bow. Run is the underwater part of a vessel’s stern. Large ships usually consist of a long parallel box – like middle section joining bow and stern. This is commonly referred to as parallel middle body. Small vessels do not usually have a parallel middle body.

Figure 1.3.4 Entrance, Run, Parallel Middle Body

1.3.5 Tumblehome Tumblehome is the inward curvature of a ship’s sides above the waterline. Expressed more technically, it is present when the beam at the uppermost deck is less than the maximum beam of the vessel. It allows any small projections at deck level to clear wharves.

Figure 1.3.5 Tumblehome

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Chapter 1 | Basic Ship Measurement and Design Terminology

1.3.6 Deadrise Deadrise is the measurement of the angle between the bottom of the vessel and its widest beam. A vessel with a 00 deadrise has a flat bottom, high numbers indicate deep V shaped hulls. The deadrise is the angle of the V on a hull, and is measured from one half of the hull’s rise from keel to chine against the horizontal. (19 degrees deadrise= 19 degree angle up from horizontal) When someone mentions a boat’s deadrise, they’re usually talking about the angle at the transom, though deadrise can refer to the angle at any point along the hull. (http://forums.boatdesign.net).

Deadrise • Angle measured between the bottom of a vessel and the transverse horizontal at the keel. • Can be referenced any point along the bottom.

1.4 Tonnage descriptions 1.4.1 Gross Tonnage Gross Tonnage has nothing to do with the weight of a vessel but rather is a measure of the ‘total’ internal volume of a ship, which includes the following non-earning spaces: machinery spaces, spaces allocated to the crew, spaces used for water ballast and the spaces used for the navigation of the ship. It is basically all of the internal volume of a vessel including space on the main deck on a fishing vessel with a totally enclosed shelter deck or where rigid doors are fitted to gear access openings. Under the Canada Shipping Act there are certain deductions allowed to the gross tonnage for fishing vessels, an example being the wheelhouse and parts of the galley for fishing vessels < 24m (LOA).

Gross Tonnage • Total internal volume of a vessel in cubic meters (with allowed deductions) multiplied by a coefficient. • Nothing to do with the weight of vessel.

Gross Tonnage used to be determined by simply dividing this volume in cubic feet by 100 (2.83 cubic meters) to arrive at the vessel’s gross tonnage. These days according to Transport Canada guidelines, the total volume arrived at in cubic meters is multiplied by a coefficient according to the formula GT = K1V, to arrive at the vessel’s gross tonnage. The tonnage measurement guidelines for large fishing vessels and small fishing vessels in Canada are different. The cut off line for tonnage calculations is < 24m in length. More information can be obtained from the following web link: http://www.tc.gc.ca/MarineSafety/tp/Tp13430/part2.h_Hlt165794710_Hlt165 794711tBM_6_BM_7_m#2.4.2

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1.4.2 Net Tonnage Traditionally the net tonnage is obtained from the Gross Tonnage by deducting “non-earning” spaces within a vessel. Traditionally the Net Tonnage more closely approximates the earning capacity of the vessel. Under the Canada Shipping Act the net tonnage of small fishing vessels (<24m in length) is now generally determined by the formula: The coefficient to be used is listed down in categories as per the type of vessel in consideration. For power driven vessels the coefficient is 0.75. Example: Gross tonnage obtained from vessel measurement and GT formula is found to be 136 tonnes. Therefore: the net tonnage is 136 x 0.75 = 102 tonnes. The net tonnage for large fishing vessels in Canada is now also deduced by formula but it takes other criteria into consideration and uses a table of different coefficients. Again more information can be obtained from the following web link: http://www.tc.gc.ca/ MarineSafety/tp/Tp13430/part2.htm#2.4.2

Net Tonnage • Gross tonnage minus deductions for nonearning spaces. • Now found by multiplying GT x Coefficient.

Displacement • Total weight of a vessel and its contents at any particular condition.

Terms

1.4.3 Displacement Tonnages The terms “Displacement” and “Deadweight” tonnage are measures of weight and are expressed in units of 1000 kilograms or metric tonnes. The displacement tonnage of a vessel, usually abbreviated to “displacement”, and represented by the symbol A, is the total weight of a vessel and its contents at any particular condition.

•L ightship Displacement is the weight of a vessel in the "as built" condition. • Load Displacement is the weight of a vessel and its contents when fully loaded.

The term displacement is often qualified as:

Light Ship displacement This is the weight of a vessel in the “as built” condition. This displacement does not include the weight of fuel, fresh water, water ballast, stores, crew and effects or cargo.

F/V ‘Skate’ Note that the displacement of F/V Skate in Condition # 1 is 215.54 metric tonnes. Note also that this Lightship displacement is the first line item in each of the pre- calculated load condition in the stability booklet.

FVSS Section 4.095

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Load displacement This is the weight of a vessel and its contents when fully loaded to its summer seasonal load line in salt water (or its designed waterline if not a load line ship). To date fishing vessels in Canada are exempt from the load line regulations under the Canada Shipping Act. The load displacement includes not only the weight of the ship, but also the weight of fuel, fresh water, water ballast, stores, crew and effects and cargo.

1.4.4 Deadweight Tonnage The deadweight tonnage of a vessel, usually abbreviated to ‘deadweight’, is the carrying capacity of the vessel. It is the weight of the fuel, fresh water, water ballast, stores, crew and effects and cargo that the vessel can carry. The deadweight can be found by subtracting the light displacement from the load displacement.

Deadweight Tonnage • The carrying capacity of the vessel. • Load ∆ - Light ∆.

Deadweight = Load ∆ - Light ∆.

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Chapter 2 Hull Shapes and Structural Terminology

Chapter 2 | Hull Shapes and Structural Terminology

2.1 Overview of Current domestic fleet structure 2.1.1 Fleet structural changes in recent years Within the context of the Newfoundland and Labrador fishery there exists a wide range of shapes and designs for fishing vessels. There still exists a large fleet of small open vessels ranging from about 18’ to upwards of 30’ that fish very close to shore and in the inner bays. The vast majority of these vessels are of modular fiberglass (GRP) construction. Some traditional wooden boats are still used many of which are now reinforced with fiberglass for added strength, reduced maintenance, and longevity. Federal government vessel replacement rules and vessel registration restrictions over the past few years have had a substantial effect on the design of other classes of vessels in the fishery. Substantial fleets of vessels within very specific length (LOA) categories have developed. In particular, cut-off points in the 34’ 11”, 44’ 11”, 54’ 11” and the 64’ 11” categories have spawned very distinct vessels within each of these groups. Traditionally (prior to the late 1980’s and early 1990’s and certainly before the cod moratorium of 1992) there existed very distinctive fleets of vessels built for particular purposes and usually classified as such. If a snap shot were taken of the industry in 1985, for example, it would show fleets of vessels designed and dedicated to the fishing of specific species. For example, a fleet of “full time” crab vessels, mostly in the larger 54’ 11” to 64’ 11” category existed; a fleet of mobile purse seiners, most of which were in the less than 55’ category, with some exceptions; a large fleet of vessels which prosecuted the cod (ground fish) fishery exclusively, ranging from small open boats right up to the 64’ 11”; as well as a fleet of offshore trawlers. Within the ‘ground fish fleet’ there were separate sectors of vessels that were classified according to the type of gear that they used. Trap boats, gill netters and trawlers (draggers) were common designations. While there was certainly some diversification amongst all of these sectors as well as others, it was very limited, especially in the earlier years, even though most inshore enterprises have always held multi-species licenses. During the period of time referenced above, most vessels were built and designed within reasonably traditional naval architectural proportions with regard to length, beam and depth despite the DFO length restrictions being in place since around 1980. However, as ground fish stocks started to decline and the inshore fleet started to venture further and further offshore in search of fish during the late 1980’s, vessel requirements changed. These changes increased in magnitude after the cod moratorium of 1992 and other ground fish quota reductions shifted the focus of the entire fleet to other less traditional species. Inactive licenses were being used as harvesters diversified to try and fill the void left by the ground fish crisis. Outdated length restrictions imposed in a different era were now being circumvented. This was accomplished by constantly increasing beam and height as a new fleet of vessels were being constructed and fully outfitted to use multiple fishing gear technology with the minimum of change over and down time. Practically a whole new fleet of very expensive, state of the art vessels have emerged over the past fifteen years whose length, beam, depth ratio, some would argue, push the envelope of standard naval architectural practice beyond even reasonable limits. In addition, construction techniques and procedures have evolved such that this fleet of vessels has been built with a life expectancy of unprecedented duration. As such, issues surrounding the stability and safe handling of these new vessels are topics that are not going away any time soon. This presents the student with some very different and even unique scenarios, which will be addressed in later chapters. In general, although vessel proportions have changed in this region, basic construction terminology is still applicable.

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2.2 Ship’s plans Three Plan Views

2.2.1 Ship’s Plans Views The three plan ‘views’ are: – Profile (as can be seen in Figure 2.2.1 below) – Half breadths (as can be seen in Figure 2.2.1 below) – Body Plan (as can be see in Figure 2.2.1 below)

Profile view is the longitudinal design layout. • Vertical body section lines. • Waterlines are parallel to base line. • Buttock lines appear as curves. Half Breadth view is the longitudinal plan view showing from the centre line to ship’s side on one side. • Waterlines are curved lines shown at various drafts. • Body section lines are straight. • Buttock lines are straight lines parallel to the centerline. Body Plan view is the transverse cross section view of the vessel. • Waterlines are straight and parallel to the base.

Figure 2.2.1 Ship Plan Views

2.2.2 The Datum lines Datum lines, when dealing with ship’s plans are:

• Body section lines are curves showing the vessels shape at different stations. • Buttock lines are straight lines parallel to the centerline views.

– The base line, as mentioned earlier this is a level line on the plan and most vertical measurements are made from this line. The base line is drawn in the profile and body plan, waterlines are parallel to the base line in these views. – The center line is really the longitudinal vertical center plane of a ship running from aft to forward. As a line on a plan it appears on the half breadths and also separating the fore body from the aft body on the body plan. – FP + AP + Amidships. The forward perpendicular line (body section line #10) in the profile view is called the forward perpendicular (FP). Body section line #0 is called the after perpendicular (AP) midway between the FP and AP is amidships which is abbreviated by teh symbol. 2-4

Chapter 2 | Hull Shapes and Structural Terminology

2.2.3 Waterlines – In profile and body plan views, waterlines run parallel with, and are numbered from, the base line. – If waterlines were exactly marked onto a ship, a diver looking up at a ship passing through the water above him would see waterlines as curved lines the same as they appear in the half breadths.

2.2.4 Buttocks – In half breadth and body plan views, buttock lines are straight lines parallel to the centerline. – In the profile view buttocks appear as curved lines.

2.2.5 Body Sections – Body section lines appear straight in profile and half breadth views. – In the body plan, each line shows the true transverse shape of the ship at the position numbered.

Figure 2.2.1 Ship Plan Views

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2.2.6 The Table of Offsets The table of offsets is a table of measurements in which the distance between datum and curved lines is recorded. Traditionally, when the naval architects completed drafting the lines plan manually for a new vessel, they would compile a ‘table of offsets’, which of course is a list of all of the half breadths, heights of decks, stringers, etc...at each of the drawn stations. From this the master ship builder would ‘loft’ the vessel’s full size faring.

Table of Offsets • The table of measurements where the distance between reference datums and curved lines is recorded.

(All information on ships plans by T. Harper) FVSS Sections 3.006 to 3.008

2.3 Ship’s area and volume terminology 2.3.1 Waterplane Area A term used extensively in discussions on ship stability is a vessels waterplane area. By definition the waterplane is the horizontal section of a ship’s hull which represents her shape in the water in that particular horizontal plane. (Dictionary of Nautical Words and Terms, author C.W,T. Layton)

Water Plane Area • Water plane area is the actual measured area in square feet or square meters of the vessels water plane in a given condition.

A simple explanation might be to visualize a vessel frozen in bay ice. If that vessel could be physically removed without disturbing the ice then the remaining hole in the ice would represent its waterplane in that particular condition. Waterplane area is simply the area in ft2 or m2 of that area. Naval architects calculate these areas for use using mathematical rules and formulae.

FVSS Section 3.007

2.3.2 Coefficients of Hull Forms Coefficients of hull form are used to define the volume and shape of the underwater form of the vessel. They are used by the Naval Architect when designing the hull form and are especially useful in powering and speed calculations. Hull form coefficients are sometimes referred to as coefficients of fineness which is a very descriptive term relating to their use. Water Plane Area Coefficient (Cw): This is the ratio between the area of a waterplane and the circumscribing rectangle having a length equal to the L.B.P and a breadth equal to the B. Mld of the vessel.

wpa = 900 ft

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Coefficients of hull form are various ratios of a vessels area or volume as compared to specified circumscribing measurements. • WPA Coefficient...Cw • Block Coefficient..Cb • MSA Coefficient...Cm

For example:

rectangle area

Coefficients of Hull Form

• Prismatic Coefficient ...Cp.

= 1000 ft2

Chapter 2 | Hull Shapes and Structural Terminology

Therefore: wpa coefficient CW =

900 = 0.9 1000 Figure 2.3.2 (A) Waterplane Area Coefficient (Cw)

The Block Coefficient (Cb): If a block has length, breadth and depth equal to the vesselâ&#x20AC;&#x2122;s length between perpendiculars, breadth moulded and depth moulded it could be shaped down until it becomes the shape of the underwater portion of the ship. The block coefficient is a measure of the fullness of the underwater form of the ship and is the ratio of the volume of this underwater form to the volume of a block with length equal to LBP, a width equal to B. Mld and a depth equal to D. Mld.

For example: underwater volume of ship is

= 1600 ft2

volume of rectangular block

= 2000 ft2

L x B x Draft Therefore Cb

1600 = 0.8 2000

Midship section area coefficient (Cm): This is the maximum cross section area of the underwater portion of the hull and is usually at amidships or just abaft of amidships. The midship section area coefficient compares the area of the maximum cross section to that of the surrounding rectangle which has depth equal to the moulded depth and width equal to the moulded breadth.

Figure 2.3.2 (B) Midship Section Coefficient Diagram (Cm)

Figure 2.3.2 (C) Block Coefficient Diagram

Prismatic Coefficient (Cp): This is the ratio of the underwater portions of the ship to the volume of the circumscribing solid having a constant section equal to the area amidships and a length equal to L.B.P.. The prismatic coefficient is a measure of the longitudinal distribution of the underwater volume of the ship.

Fishing Master Program, Ship Construction and Stability Book I

Figure 2.3.2 (D) Sketch showing prismatic coefficient derivation. (Source: stab III manual)

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Chapter 2 | Hull Shapes and Structural Terminology

2.4 Hull shape terminology 2.4.1 Round Bilge A vessel is said to be of round bilge hull form when a transverse view shows an unbroken curve between keel and sheer. Small vessels have very shapely rounded hulls whilst a very large ship may have a flat bottom and straight sides connected by a relatively small radius. Most “traditional” Newfoundland and Labrador wooden fishing vessels such as trap boats and longliners are of the round bilge hull form. Vessels with a round bilge hull can have a very easy motion at sea and it is the traditional shape for ships, however much variation in hull shape is possible and more common today. Refer to Figure 2.2.1.

2.4.2 Hard Chine This hull shape is sometimes referred to as a “V “bottom, which is very descriptive of its shape. Hard chine hull forms show a distinct corner at the junction of topsides and bottom with both sides and bottom being quite flat. This shape makes construction relatively quick and easy as large sheets of metal can be wrapped around the frames with little prior treatment. Small boats planked with plywood show similar advantages. The term hard chine indicates an angle with little rounding, as is common in the construction of steel vessels. A soft chine would be more rounded but still involve the meeting of distinct planes, which can be seen in some fiberglass hull forms. Some texts argue that “a hard chine hull form may dampen roll somewhat more than round bilge but will tend to slam more. Round bilge may behave better in heavy seas, but a single chine hull will be better in small seas”. (“Simple Ship Stability” by Alfred Carver)

2.4.3 Double and Multi-chine hull forms Double chine hull forms show two distinct corners between the keel and sheer line whereas multi-chine hulls might show several corners. By increasing the number of chines the hull can very closely approximate a round bottomed hull.

Figure 2.4.3 Examples of hard chine hull form (left), double chine hull form (middle) and multiple chine hull form (right)

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2.4.4 Multi-Hulled Craft The modern catamaran has two separate hulls joined by the deck structure. It is a direct descendant of twin hulled canoes used many years ago. Each hull tends to be long and narrow making it relatively easy to propel but the spacing of the hulls results in a large flat platform with less tendency to roll than mono hull craft. A trimaran is another multihull but has one main hull with an outrigger on either side. The double hulled catamaran has found wide use in a variety of applications including pleasure yachts, ferries, fishing boats and research vessels, and ranges Figure 2.4.4 A modern catamaran built in Newfoundland for the in length from two meters to 50 inshore/offshore fishery meters and larger. The trimaran hull configuration is mainly restricted to sailing craft. Multi-hulled craft are expensive to build when compared to vessels with a single hull but offer a number of advantages for certain applications. (Harper) Multi-hulls derive their increased stability from their wide beam. This applies to both catamarans and trimarans. When they heel, the transfer of buoyancy from the weather hull to the lee hull is over a large distance. Hence there is a large shift of B and so a large BM. (This term will be discussed in a later chapter but is basically the distance from the center of buoyancy to the metacentre). As a consequence, the metacentre is very high making the distance from G to M very large. (I.e. the vessel has very large initial transverse stability.) A significant danger with multi-hulls is lifting the weather hull clear of the water, with the possibility of wind forces producing a heeling moment which may be sufficient to capsize the boat. Smaller trimarans may be designed to lift the weather float, and side decks may be made of netting, to reduce windage. Since they are so stable, their period of roll is very small and the amplitude of rolling is severely restricted. This makes them very comfortable craft, with good working deck areas. (Simple Ship Stability by Alfred Carver)

2.5 Hull Integrity Terminology 2.5.1 Closed Construction According to the Small Fishing Vessel Inspection Regulations (CSA) the definition of a fishing vessel of closed construction is a fishing vessel of which more than 50% of the length is covered full width, at or above the gunwale level, by decks or permanent enclosures. http://www.tc.gc. ca/actsregulations/GENERAL/C/csa/regulations/070/csa075/csa75.html Another legal interpretation taken from http://laws.justice.gc.ca states that “a closed construction ship is a ship that has a fixed structural deck covering the entire hull above the deepest operating waterline and that, when the open wells or cockpits fitted in the deck of the ship are flooded, is not endangered.” This is also the principle part of the definition to be included in the new ‘Fishing Vessel Safety’ regulations currently proposed by Transport Canada along with minimum freeboard requirements. Fishing Master Program, Ship Construction and Stability Book I

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2.5.2 Open Construction With respect to fishing vessels, open construction refers to any vessel other than a vessel of closed construction.(SFV Inspection Regulations)

2.5.3 Watertight With respect to a closed vessel, watertight refers to the prevention of the passage of water through the structure in any direction under a head of water for which the surrounding structure was designed (equivalent to ISO 12216 Watertight degree #1).

2.5.4 Weathertight A structure is termed to be weathertight if it is capable of preventing the passage of water through it in ordinary sea conditions (equivalent to ISO 12216 Watertight degree #2). NOTE: The degree of water tightness as defined by ISO 12216 is summarized as follows: a) Degree #1: Degree of tightness providing protection against effects of continuous immersion in water. b) Degree #2: Degree of tightness providing protection against effects of temporary immersion in water. c) Degree #3: Degree of tightness providing protection against splashing water. d) Degree #4: Degree of tightness providing protection against water drops falling at an angle of up to 15Â° from the vertical.

FVSS Sections 3.002 and 3.003

2.6 Structural members and parts of fishing vessels 2.6.1 Identification of various equipment and parts of a fishing vessel: Common Structural Definitions Aft: - Towards the stern, near the stern After peak: - Enclosed part of the vessel immediately forward of the stern frame Ballast: - Heavy sub stance put into a ves sel to im prove sta bil ity or to increasesubmersion of the propeller. (note: Can be permanent or temporary...fluid) Beam: - Transverse member that goes between opposite frames or ribs to support the ships sides against collapsing stresses and support the deck. Bilge: - Rounded part of a vessels underwater body where the side curves round towards the keel. Generally the bilge is the drainage space within a vessel.

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Bilge Keel: - External keel placed along the bilge of a ship to help dampen roll. Bollard: - Large and firmly secured post of circular section used to secure the mooring lines. Bulkhead: - Transverse (or Longitudinal) vertical partitions in a vessel to divide interior compartments. Chain locker: - Compartment in which anchor cable is stowed and the end board end secured.... (note: Locally many fishers refer to anchor cable as anchor chain) Cleat: - Metal or wooden fitting having two projecting horns and fastened securely at the middle. Used for securing or controlling ropes. Collision Bulkhead: - Unpierced bulkhead extending to the upper deck. Placed about 0.05 of vesselâ&#x20AC;&#x2122;s length from the stem. Limits entry of sea in event of head on collision. Covering Board: - Plank that overlaps the seam between the planking of the side of a wooden ship and the outboard deck plank. Deadlights: - Plates fitted over port holes to protect them and to prevent light from shining outside. Deck: - Horizontal flooring or plating above the bottom of the vessel. May be continuous or partial. Deck Head: - Underside of the deck. Double Bottom: - Space between the inner and outer bottom plating of the hull. Entrance: - Form of the fore part of a vessels hull below the waterline. Fall: - Hauling part of a purchase False keel: - Additional keel fitted to the main keel to protect it in the event of the vessel taking ground. Flush Deck: - Upper deck that runs the full length of the vessel and has no poop or forcastle deck. Floors: - Transverse members erected vertically that connect lower ends of frames on opposite sides of the vessel. Forestay: - Stay of the foremast, extending from the masthead to a position forward. Fore Peak: - Space between the forward collision bulkhead and the stem plating. Framing: - System of frames, floors and intercostals to which outside plating is attached. Freeing Port, Scuppers or floodgates: - O penings in the bulwarks allowing water shipped on deck to flow over the side. Gussetts, Brackets and Fish Plates: - Terminology used to describe different structural connecting plates in steel vessels. Halyards: - Ropes by which sails, yards, flags and gaffs are hoisted

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Chapter 2 | Hull Shapes and Structural Terminology

Hatch: - Opening in the deck that gives access to the hold or space below. Hatch Coaming: - Raised wall of steel or other material around a hatch. Raises the hatch covers above the level of the decks and carries fittings for securing hatch covers. Hawse pipe: - Tube through which the anchor cable runs from the anchor winch to the anchor, out through the ships bows. Intercostal: - Between the ribs. Applied to structures or members between the floors or frames of a vessel. Keel: - Principle member of a ships construction. Lies fore and aft along the center line of the bottom. Keelson: - Internal keel fitted immediately above the main keel. ood grown or shaped to a right angle form. Used for connecting and supporting two Knee: - W members perpendicular to one another. Steel or iron plates, roughly triangular, used for the same above purpose. Manhole: - Perforation in a boiler shell, tank top or other enclosed space (deck) to allow a man to enter. Margin plate: - Plating forming the side of the double bottom ballast tank. Mast head: - The upper part of a vessels mast. Midship Body: - That part of the hull of a ship in which there is little change in transverse shape. Pillars: - Vertical members of a ships construction, by which decks and beams are supported and the transverse form of a vessel is maintained in the vertical plane. Plating: - Iron or steel sheets forming part of a ships deck or hull. Planking: - Wooden lengths of timber used to cover a vesselâ&#x20AC;&#x2122;s deck or hull Quarter: - That part of the vessel between its beam and the stern. Rail: - Top of the bulwarks. Running Riggings: - All ropes rove through blocks and worked as may be necessary, as distinguished from standing riggings. Shaft tunnel: - Enclosed space, between the engine room and the stern gland through which the propeller shaft extends and in which are the shaft bearings. Shelter Deck: - Deck above the main deck when it is not permanently closed against wind and weather. It is thus exempted from certain tonnage measurements. Spurling pipe: - Tube leading from the forcastle deck to the cable locker (chain locker) which encloses the cable. Standing Riggings: - Shrouds, stays, trusses, pendants, etc., that support masts, yards, booms, and gaffs by being fixed and immovable.

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Chapter 12 | Interpreting Stability Booklet Data

12.1 Transport Canada Approval Process 12.1.1 Requirements for, and process to get stability booklet approval At present in Canada, Section 29 of the Small Fishing Vessel Inspection Regulations requires that a vessel have an approved stability booklet if a vessel is used to catch capelin or herring. Additionally, Section 48 of the same Regulations permits an inspector to request any tests necessary to verify a vessel’s seaworthiness. Essentially a Transport Canada Ship Safety Inspector has the authority to request that any fishing vessel requiring a valid CSI Certificate, whom he/she feels necessary, be inclined and have a stability booklet produced for that vessel. In fact it is their mandate to take all measures necessary to ensure the safety of vessels under their jurisdiction. At present all fishing vessels of 15 gross tonnes or more fall under CSI jurisdiction. In Ships Safety Bulletin (#04/2006) issued on 2006-03-07, Transport Canada clearly stated the above as well as requested that all vessel owners complete a questionnaire, to determine if their vessel was subject to any of a number of stability ‘risk factors’. Those factors as identified by Transport Canada are: – Vessels fishing for capelin or herring; – Vessels using trawls, purse seines or towing any heavy gear; – Vessels fitted with an Anti-Roll Tank; – Those operating from December to March (icing season); – Any vessels operating beyond Near Coastal Class 2 Voyages (25 nm); – Any vessel transferred to Canadian Registry; and – Vessels that have failed the simplified stability test. While it is impossible to predict, in all likelihood the new Fishing Vessel Safety Regulations when implemented will capture many, if not all, vessels within these categories. FVSS Sections 4.002 – 4.005

This bulletin can be found at: http://www.tc.gc.ca/marinesafety/bulletins/2006/04_e.htm As was discussed in Chapter 6, to obtain a stability booklet for a fishing vessel the services of a naval architect must be obtained. After the need for an approved stability booklet for an existing vessel has been identified, essentially the first step that a vessel owner must take is to contact a naval architect. To prepare the booklet the naval architect needs hull particulars taken from the vessel plans or, if plans are not available, then the vessel will need to be taken out of the water and measurements taken so that a computer generated hull form can be developed. As was discussed in an earlier chapter this is needed to determine the position of the metacentre or M.

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Chapter 12 | Interpreting Stability Booklet Data

The next step involves subjecting the vessel to an inclining experiment in order to find the position of the vessel’s center of gravity in the lightship condition and subsequently its initial GM. The architect will also interview and discuss with the Owner/Master the operational requirements of the vessel. Particulars as to which fishing gear and equipment will be on board during different operations as well as its position and weight are all important considerations that must be factored into the stability calculations. There are two methods to get a stability booklet approved in Canada for a fishing vessel: 1. The booklet can be stamped by a professional engineer (P.Eng./Ing) with naval architecture expertise or an exclusive surveyor to: American Bureau of Shipping; Lloyd’s Registry; Det Norske Veritas; Germanischer Lloyd; or Bureau Veritas, in which case Transport Canada need not be directly involved. A copy of the stamped booklet is required to be sent to Transport Canada for monitoring purposes only. 2. Alternately and which has been the normal case, Transport Canada is asked to approve the booklet after it has been fully prepared by the naval architect. In this case a Transport Canada Inspector must witness the inclining experiment. During the preparation of the booklet, as the information is compiled, the naval architect may be confronted with a situation whereby some restrictions, additions or movement of onboard equipment will be necessary to permit the vessel to meet the minimum or maximum stability standards as set down in the guidelines of Stab 4 (Listed in Chapter 7). It is very common for a vessel to require more ballast or for a fish hold size restriction to be placed upon the vessel for certain operations. Movement of winches or other equipment onto a lower deck is sometimes necessary as well to allow the vessel to meet the requirements. At this point it is important for the vessel owner and Master to work very closely with the naval architect to consider the different options available. The vessel must meet the minimum requirements as set down in the Stab4 guidelines for all conditions of load before the naval architect will submit the booklet to Transport Canada for approval. Upon receiving the booklet from the naval architect, Transport Canada will normally conduct an initial audit of the content to verify that the vessel meets the required standards and initial checks are conducted to confirm its authenticity. This initial process normally only takes a few days and, if everything checks out, then an interim CSI Certificate is issued for the vessel, which allows it to proceed to sea. A copy of the ‘preliminary’ stability booklet is sent on board for use by the Master. The final approval process whereby Transport Canada puts its stamp of approval on the stability booklet involves a very detailed examination of all of the information and calculations made in the stability booklet to ensure its accuracy. This process is very time consuming and often requires considerable communication between the naval architect who compiled the booklet and the Transport Canada Inspector who is tasked to audit it. At the end of this process the booklet is stamped by Transport Canada and sent to the owner to be retained onboard the vessel. FVSS Sections 4.021 to 4.044

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Chapter 12 | Interpreting Stability Booklet Data

12.2 Stability Booklet Information 12.2.1 Notes to the Master Located near the front of the stability booklet, the Notes to the Master section contains some very important information regarding the safe operation of the fishing vessel in question. The Master should review these in consultation with the naval architect that prepared the booklet to get a good understanding of the general stability conditions and operational requirements of the vessel. The Notes to the Master section summarizes in a general sense what the naval architect has found to be safe operating practices for that particular vessel. Since this information is critical to the safety of the vessel it should be strictly adhered to at all times. The notes to the Master, or sometimes referred to as the Notes to the Skipper section, are very similar in format for all vessels. They each contain critical safety information pertinent to the vessel involved. Recent changes to the guidelines for the preparation of stability booklets for fishing vessels in Canada have introduced a standardized format for the delivery of this information for all new stability booklets. Below is an example of this new format: 1

Purpose

To disclose the basis upon which the Naval Architect produced the Trim and Stability Booklet and to present operating conditions for the vessel that meet the Transport Canada Marine Safety (TCMS) criteria in the SFV/LFV Regulations and TP7301.

There is no intent to direct the Master only to provide him with stability information that may assist him in carrying out his responsibilities.

This Manual of Trim and Stability constitutes a baseline from which the vessel may not be modified in any way that affects its stability without the written approval of TCMS.

Masterâ&#x20AC;&#x2122;s Responsibilities

It is the responsibility of the Master to ensure that the conditions presented in the Stability Booklet reflects the vesselâ&#x20AC;&#x2122;s loading conditions and modes of operation.

Compliance with the stability criteria does not ensure immunity against capsizing, regardless of the circumstances, or absolve the Master from his responsibilities. The Master should therefore exercise prudence and good seamanship having regard to the season of the year, weather forecasts, navigational zones, and should take appropriate action as to the speed and course warranted by the prevailing circumstances.

Before a voyage commences the Master should ensure that the cargo and equipment have been properly stowed and secured.

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Loading Particulars

Ground Fish is loaded sequentially aft to forward.

The maximum load of ground fish is XX,xxx lbs

No fish is carried on deck

Fish species include ground fish, crab and shrimp; no capelin or herring.

No cargo is carried suspended in a liquid.

Pen boards are used at all times.

Ground fish is loaded in bulk, crab is carried in pans and shrimp is carried in bags.

A maximum of XX.xx L/Tons of ice is carried in the Pen X and Y Port, Centre and Starboard.

Consumable Particulars

Fuel Oil is used from the aft tanks simultaneously prior to using the forward tanks.

Lube Oil is at an operation level in all conditions.

Hydraulic Oil is at an operation level in all conditions.

Fresh Water is used from the aft tanks simultaneously prior to consuming from the forward tank.

Down Flooding

Description the DF point: hatch coaming located at VCG = xx.xx, LCG = xx.xx aft of amidships, and TCG = x.xx feet port and starboard.

Before a voyage commences the Master should ensure that closures in way of down flooding points have been closed and secured.

The following structure is included in the cross curves: deck house and shelter deck.

Specific Gravity (SG) or unit weight

Ground Fish = 0.793 and includes a 2/3 fish to 1/3 ice mixture.

Crab = XX.xx pounds per box (state if weight of ice and box included in the total weight allowable).

Shrimp = XX.xx pounds per bag (state if ice is included in the total weight allowable).

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Chapter 12 | Interpreting Stability Booklet Data

Specific Gravity (SG) or unit weight

Capelin = 1.001 (TP 7301).

Other such as RSW.

(Note: if a nonstandard SG state how derived).

Free Surface (FS) Effect

Procedures that would limit FS: pressing up tanks, using pound boards.

Conditions where action is required: EG: all conditions with ice acretion.

The following catches have free surface: capelin, herring, and RSW (aeration systems)

Anti-Roll Tank (ART) or Stabilizers

This stability booklet considers the effect of ART operation upon static stability only. For operating and emergency procedures reference Manual “ABC-123”. It is strongly recommended a summary be included in the stability booklet.

The Master and any crewmember standing watch on the vessel should be familiar with all aspects of the ART operation such as: the conditions for which the ART should be dumped; how the ART is dumped; and how long dumping takes. The ART dump valves should be well maintained and an occasional practice dumping should be performed by the Master to demonstrate correct operation of the valves. “Dumping” of ART fluid refers to overboard discharge of non-polluting substances.

Restrictions in accordance with the vessel’s operating certificate SIC29: ART and stabilizers are not used in the following conditions for example: below freezing, in beam seas, beyond a maximum allowable wave height and/or wind speed, with ice accretion, with paravanes. [Refer to Ship Safety Bulletin]

Ballast

Water ballast was not used. (Note: if Water Ballast is used the sequence of use must be stated).

Extent of permanent ballast: see diagram and description on page X.

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Chapter 12 | Interpreting Stability Booklet Data

Fishing Gear to be added and/or removed

Trawling: winch, warps, doors, net and gantry = x.xx L/Tons.

State if multiple sets of gear can be carried simulaneously.

State which gear must be removed before installing any other gear or equipment. [Provide a table of gear weights].

Seining: skiff and net = x.xx L/Tons.

Gillnetting: hauler and table = x.xx L/Tons.

Crab: hauler = x.xx L/Tons. xxx pots maximum and xxx boxes.

Winter Operation

Date: MM/DD/YYYY (Note: dates must match the SI 29 certification).

Reference Ice Accumulation Calculations: see page #X.

State Restrictions: pens X.p, X.c, and X.s must be sealed off and made water tight to the satisfaction of the Marine Safety Inspector.

Operating Restrictions

Voyage Restrictions should match SI 29 certificate. EG: HT II from x to y.

Tanks not be used: see item 4 above.

Holds blanked off: see item 11 above.

Equipment not used: A seine skiff was not onboard in any condition. FVSS Sections 4.052 to 4.057

Naval architects develop stability data these days using computer software programs to compile all of the required information. The stability booklet for F/V ‘Skate’ was produced using General Hydrographic Services software (GHS), which is very popular. Much of the information in the booklet is based on hydrostatic data or in simple terms, it is a direct function of the shape of the underwater portion of the vessel. As discussed in Chapter 1, the baseline in many fishing vessel stability 12-8

Hydrostatic Data • The difference between the hydrostatic base line, AP, FP and as compared to those from the vessels plans. • All hydrostatic data in the sample stability booklets are based on or in reference to the hydrostatic base line, AP, FP and . • To find a vessels hydrostatic trim corrections must be applied to its actual drafts before comparing draft fwd. and draft aft to calculate trim.

Chapter 12 | Interpreting Stability Booklet Data

booklets, including F/V ‘Skate’, is shown to intersect the keel at midships. As this baseline is not parallel with the keel, for simplistic purposes we will refer to it as the ‘hydrostatic baseline’. The aft perpendicular (AP) and the forward perpendicular (FP) are 900 to this line and the midships line is midway between the two perpendiculars.

F/V ‘Skate’ Page 6

Draft and Baseline Particulars for F/V Skate. (page 6 of F/V 'Skate' stability booklet)

12.2.2 Tank Plan and Tank Status tables Most stability booklets show a profile and plan view of the vessel with all onboard tanks sketched in and labeled according to their position on board the vessel. The Tank Plan for F/V ‘Skate’ can be seen on page 7 of the Skate booklet. In addition to the fuel and fresh water tanks, the fish hold consist of two refrigerated sea water (RSW) tanks, referred to as the Fish Hold Port and Fish Hold Starboard tanks.

Figure 12.2.2 (A) Tank Plan from F/V ‘Skate’

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Chapter 12 | Interpreting Stability Booklet Data

Immediately following the Tank Plan are the Tank Status tables which show applicable information pertaining to each individual tank. Tank Status tables are normally shown for tanks at 100%, 98%, 75%, 50%, 25% and 10% full. As can be seen from the table below and from the different tank capacity tables in our sample booklets, for each tank the following information can be extracted: – The applicable tank is identified and the % full; – The specific gravity of the liquid in question (tonnes per cubic meter);

Terms • One Metric Tonne = 1000 kg. • Tank Status Tables are compiled with all on board tanks shown at a stated level of fill. Each table lists all tanks.

– The weight of liquid in the tank at that level; – The longitudinal position of the center of gravity of the tank, at the specified level, from the midships baseline, at this level of trim; – The transverse position of G from the centerline; - The vertical position of G from the baseline; and – Any free surface moments associated with the tank in this condition.

Figure 12.2.2 (B) Tank Status tables copied from page 9 of F/V 'Skate' stability booklet

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FVSS Sections 4.071 to 4.077

Chapter 12 | Interpreting Stability Booklet Data

12.2.3 Tank Characteristic Tables Tank Characteristic tables or Tank Capacities tables are normally located in the back part of the stability booklet (check table of contents). Each of these tables is specific to a given tank. They usually display the following information: – The volume in gallons or liters of the tank at different percentages of fill;

Tank Characteristic Tables • Are compiled 'one per tank'. • Tank capacities in liters or gallons are listed here but not in tank status tables.

– The corresponding weight of the liquid for each tank load percentage. ( % full); – The longitudinal position of the center of gravity of the tank, at the specified level, from ; – The transverse position of G from the centerline; – The vertical position of G from the baseline; – Any free surface moments associated with the tank at the different levels of fill; – The GML is also included for each percentage of fill for each tank. This is generated by the architects program in computing other data and is basically the virtual distance of rise for the centre of gravity of the tank contents due to the free surface effect in the longitudinal direction.

F/V ‘Skate’ Page 58 to 62

Figure 12.2.3 Tank Characteristic Table for the starboard fresh water tank, taken from page 61 of F/V ‘Skate’ booklet

FVSS Sections 4.078 to 4.086

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Chapter 12 | Interpreting Stability Booklet Data

12.2.4 Interpret light ship condition information As was discussed earlier, Lightship condition includes only the weight of the vessel, in its ‘as built’ condition (no fishing gear, supplies, crew effects, fuel, ice etc...). This is the status of the vessel that is depicted in Condition 1 of the standard stability booklet. A closer look will show that the following information is listed:

F/V ‘Skate’ Pages 15 and 16

– The actual lightship weight of the vessel; – The position of the LCG, TCG and VCG in this condition; – The vessels drafts; – Hydrostatic properties such as LCB, VCB, LCF, GML and GMT; – Critical down flooding points information: LCP, TCP, VCP and Height (from the water); – The freeboard status of the vessel. The second condition listed in the stability booklet, Condition 2, is the Primed Lightship Condition. This includes: – The actual lightship weight of the vessel; – The crew and effects; – Minor consumables; – The new position of the LCG, TCG and VCG in this condition; – The vessel’s drafts in this condition; – Hydrostatic properties such as LCB, VCB, LCF, GML and GMT in this condition; – Critical down flooding points information: LCP, TCP, VCP and Height (from the water) in this condition; – The freeboard status of the vessel in this condition. – In some stability booklets, onboard fishing gear may also be included in the Operational or Primed Lightship Condition. This is not the case however in the booklet for F/V ‘Skate’ FVSS Sections 4.089 to 4.126

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Chapter 12 | Interpreting Stability Booklet Data

12.2.5 Interpret port departure condition information The Port Departure condition in the stability booklet includes all items that would normally be on board that particular fishing vessel when it is ready to sail for a fishing trip. If a vessel is used for multi-specie and multi-gear types then it is not uncommon to have conditions prepared for each type of fishery. For example, the condition may be Port Departure Capelin or Port Departure Shrimp. Typical items that would be included into port departure conditions are: – The actual lightship weight of the vessel; – The crew and effects; – Minor consumables; – Onboard fishing gear (such as seining gear) or in the case of F/V ‘Skate’, crab pots; – Tank details in the nearly full condition (including free surface moments) note that the RSW tanks are also included in the F/V ‘Skate’ booklet.; – Ice in the fish hold if this is the normal operating procedure; – If an ART is fitted, details on it; – The positions of all weights aboard in terms of their centres of gravity; – The new position of the vessels LCG, TCG and VCG in this condition. Note that the LCG is different than that listed in the Tank Status and Tank Characteristics tables for this level of fill. This is because the vessel is at a different level of trim.; – The vessel’s drafts in this condition; – Hydrostatic properties such as LCB, VCB, LCF, GML and GMT in this condition;

Port Departure Information • LCG and LCB are in reference to the hydrostatic . • TCG and TCB are in reference to the longitudinal centre line. • VCG and VCB are in reference to the hydrostatic baseline. • GML - Longitudinal GM • GMT - Transverse GM • LCP - Position of critical downflooding point in reference to hydrostatic . • TCP - Position of critical downflooding point in reference to longitudinal centreline. • VCP - Position of critical downflooding point in reference to hydostatic baseline.

F/V ‘Skate’ Pages 17 to 20

– Critical down flooding points information: LCP, TCP, VCP and Height (from the water) in this condition; – The freeboard status of the vessel in this condition; – A table showing the righting arms (GZ levers) at different heel angles and other information such as height of flooding points at that angle of heel and the vessel’s longitudinal hydrostatic trim at the different heel angles;

Fishing Master Program, Ship Construction and Stability Book I

Trim • The trim listed under hydrostatic properties is hydrostatic trim not actual physical trim.

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Chapter 12 | Interpreting Stability Booklet Data

– A table with a list of the Transport Canada Stab 4 minimum and maximum requirements and the actual value attained for the vessel in question in this condition. This is set up somewhat as a comparison of the two, to see the reserves of stability beyond regulated minimums that the vessel has or does not have. In newer books the value attained for the vessel will usually be preceded by a P or an F as either passed or failed to meet the minimum accepted regulatory standard; – The last page of information that is given for each condition of load normally consists of three graphs.

1. The first one being the actual GZ curve for that condition. The information displayed in the previous tables can be seen graphically as well as other critical information can be gleaned as was discussed in previous chapters. The actual shape of this curve is indicative of the stability characteristics of the vessel in that condition.

2. The next curve represents the actual area under the GZ curve at different angles of heel. Information taken from the Righting Arm vs Heel Angle table for different angles of heel are plotted to graphically show the amount of area that is available at different angles of heel. From this graph the trend with regard to changes in righting energy at different angles of heel can be easily seen.

3. The third graph simply shows the corresponding height of the vessels critical downflooding point, from the surface of the water, as the vessel heels through increasing angles. The distance in the upright was mentioned above as its height above the water. This height will be maximum at 0° heel and nil at the point of downflooding.

FVSS Sections 4.128 to 4.157

12.2.6 Interpret other conditions contained in the stability booklet There are many different conditions that might be included into a typical stability booklet. With the exception of the Lightship Righting Arm vs. conditions, most pre-calculated conditions in the booklet start with Heel Angle Tables a sketched profile and plan view of the vessel showing roughly the • Origin depth in the percentage each tank is filled. All conditions are set up in the same righting arm vs. heel systematic manner as per the amount of weights on board such as angle tables is the fuel, fish, ice, fresh water, fishing gear and other items. Free surface distance from the actual water to the moments are calculated for each partially filled tank per condition as hydrostatic baseline well as for partially filled fish holds with fish like capelin and herring. at various heel angles. Each condition in the stability booklet includes all items that would normally be on board that particular fishing vessel at that stage of the fishing trip. The ‘Weight and Displacement Status’ table is set up beginning with the lightship information with all other items listed. As with the previously discussed conditions, the following is included: - The actual lightship weight of the vessel; - The crew and effects; - Minor consumables;

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Chapter 12 | Interpreting Stability Booklet Data

– On board fishing gear (such as seining gear); – Tank details including RSW tanks in their current condition (including free surface moments); – Estimate of amount of ice in the hold in the current condition; – Fish on board in current condition; – Details of ART (if present); – The positions of all weights aboard in terms of their centres of gravity; – The new position of the vessel’s LCG, TCG and VCG in this condition with all of the above weights included; – The vessel’s drafts in this condition; – Hydrostatic properties such as LCB, VCB, LCF, GML and GMT in this condition; – Critical down flooding points information: LCP, TCP, VCP and Height (from the water) in this condition; – The freeboard status of the vessel in this condition; –

A table showing the righting arms (GZ levers) at different heel angles and other information such as height of flooding points at that angle of heel and the vessel’s longitudinal trim at the different heel angles;

– A table with a list of the Transport Canada Stab 4 minimum and maximum requirements and the actual value attained for the vessel in question in this condition. This is set up somewhat as a comparison of the two to see the reserves of stability beyond regulated minimums that the vessel has or does not have. In newer books the value attained for the vessel will usually be preceded by a P or an F as either passed or failed to meet the minimum accepted regulatory standard; and – The last page of information that is given for each condition of load normally consists of three graphs:

1. The GZ curve for that condition, whereby the information displayed in the previous tables can be seen graphically. Other critical information can be gleaned as discussed in previous chapters. The actual shape of this curve is very indicative of the stability characteristics of the vessel in that condition;

2. The actual area under the above GZ curve at different angles of heel. Information taken from the Righting Arm vs Heel Angle table for different angles of heel are plotted to graphically show the amount of area that is available at different angles of heel. From this graph the trend with regard to changes in righting energy at different angles of heel can be easily seen;

3. The corresponding height of the vessel’s critical down flooding point, from the surface of the water, as the vessel heels through increasing angles. The distance in the upright was mentioned above as its height above the water. This height will be maximum at 0° heel and nil at the point of downflooding.

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Chapter 12 | Interpreting Stability Booklet Data

12.2.7 Hydrostatic tables and curves The Hydrostatic tables contain some important information on the vessel in question. There are usually several tables listed into a stability booklet according to the vessel’s longitudinal hydrostatic trim, which is indicated at the top of the table. The table is normally organized with the vessel’s mean draft located on the left side of the table and applicable information corresponding to that draft listed in several other columns. The following information can be directly extracted from the hydrostatic table for each of the listed drafts: 1. The vessel’s displacement;

Three (3) Curves • Actual GZ curve in that condition. • Curve Showing Area under GZ curve at various heel angels • Curve showing height or downflood points at various heel

2. The position of the LCB in reference to the hydrostatic amidships;

F/V ‘Skate’

3. The height of the VCB from the hydrostatic baseline; 4. The TPC or TPI of the vessel at different drafts;

Pages 39 and 40

5. The position of the vessels LCF in reference to the hydrostatic amidships; 6. The moments to change trim (MCT 1cm. or MCT 1in.); and 7. The KML and KMT.

FVSS Sections 4.159 to 4.172

Usually located immediately after the hydrostatic tables, the curves are organized to provide several specific hydrostatic values for the vessel at corresponding mean drafts. These curves correspond to the preceding hydrostatic table specific to a given trim. The first hydrostatic table and hydrostatic curves in the stability booklet as well as the cross curves of stability table and curves are usually for the vessel at level trim or as we see in F/V ‘Skate booklet’, no trim.

CAUTION! • Be careful to use the hydrostatic table, curves and/or cross curves for the vessels current hydrostatic trim.

The hydrostatic properties curves (commonly referred to as the hydrostatic curves) are set up to show the vessel’s mean draft on the left side, with the general scale of desired values along the bottom or along the top of the table. Several curves are indicated on the graph and are usually identified by a number or actually labeled to show their purpose. At the bottom of the graph there is usually a chart to show how to convert the extracted value into the actual desired hydrostatic information. Below is a hydrostatic properties table out of F/V ‘Skate’ booklet, page 40. An explanation of how to extract each different value listed follows.

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Chapter 12 | Interpreting Stability Booklet Data

Note: A pair of dividers would be an asset in using these tables.

Figure 12.2.7 Excerpt taken from page.40 of F/V â&#x20AC;&#x2DC;Skateâ&#x20AC;&#x2122; stability booklet

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1. To find the vessel’s displacement corresponding to a mean draft, lightly draw in a horizontal line corresponding to the draft and where it crosses the #1 curve drop a vertical. The number extracted from the scale, at the bottom of the table, would then be multiplied by 2, as per the instructions given. As an example, let’s assume that F/V ‘Skate’ has a mean draft of 3.4 meters. We first draw an horizontal line at the 3.4 meter level. Where this line intersects curve #1, drop a vertical line to the base of the graph, to get a value of approximately 125 units. To find the displacement of the vessel, we then multiply this value by 2. This gives us a displacement of approximately 250 metric tonnes. If we check back to the tables on page 39, for a mean draft of 3.4 meters, the displacement is listed as 248.16. This confirms that our approximate value from the curve is correct. The values in the table are more precise, since graph interpolation errors are avoided. FVSS Sections 4.173 to 4.184

2. To find the position of the LCB or longitudinal center of buoyancy we use the top scale. For a given draft we follow across horizontally until we cross the # 2 curve where we draw a line vertically and read the value off the scale at the top of the chart. As an example, for the mean draft of 3.4 meters, we draw a vertical line at the intersection of curve #2, to read a value of approximately 0.1 meters forward of the midships line. As a check, we refer back to the Hydrostatic table on page 39 and note a LCB value of 0.133 meters fwd. This confirms our finding from the curve, but once again it highlights the fact that the tables are more precise.

Reminders • WPA (waterplane area) can be extracted directly from hydostatic curves (after the conversion factor is applied). • Remember to use top scale in reference to hydrostatic to find the LCF and LCB.

3. To find the VCB or vertical centre of buoyancy for a corresponding mean draft, again we follow along a horizontal line from a given draft value until we cross the #3 curve and drop a vertical. As per the instructions, the value extracted at the bottom will then be multiplied by 0.02. As an example, again for a draft of 3.4 meters, the value extracted is approximately 121 units. Multiplied by 0.02 this give us a VCB value of approximately 2.42 meters. As a check, note from the table on page 39 that the VCB value for a draft of 3.4 meters is 2.427 meters. 4. To find the vessel’s TPC or tonnes/centimeter of immersion value at level trim and for a corresponding mean draft we follow along a horizontal line until it crosses the #4 curve and drop a vertical down to extract a value from the table. This value is then multiplied by 0.007 to get the TPC value for that particular mean draft. For a mean draft of 3.4 meters, we extract a value of approximately 230 units from the bottom scale. Therefore the TPC = 230 x 0.007 = 1.61t/cm. Note that this is also the TPC value that is tabulated for a draft of 3.4 meters on page 39. 5. To find the WPA or waterplane area at a given draft, we also use the #4 curve. To calculate the WPA however, according to the given scale for this condition, we multiply the extracted value by 0.683 to get the WPA in square meters. For a draft of 3.4 meters the WPA = 230 x 0.683, which equates to 157.08 m2.

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Chapter 12 | Interpreting Stability Booklet Data

6. To find the position of the LCF or longitudinal centre of flotation we use the top scale to read the distance that it is located either forward or aft of hydrostatic amidships for the given mean draft. We simply follow along horizontally from a particular draft until we cross the #5 curve. A vertical is then extended from that point up to the scale at the top of the table to find the desired value. Using a mean draft of 3.4 meters, we see that the LCF is located approximately 0.6meters aft of amidships. To confirm this we notice that the LCF value from the table on page 39 is 0.631a. 7. To find the MCTC for this condition of trim we follow a horizontal line drawn at the required mean draft until it crosses curve #6. We then draw a vertical line from this down to the bottom scale. The value extracted must then be multiplied by 0.02 according to the instructions given to obtain the MCTC. For a mean draft of 3.4 meters, the value that we extract from the general scale at the bottom is 146. This is multiplied by 0.02 to get a MCTC value of 2.92 m-mt/cm. 8. To find the KML or vertical distance from the keel to the longitudinal metacentre we use curve #7. Again we enter the table with the mean draft and follow along horizontally until we cross curve #7. A vertical is then dropped to extract a value from the scale at the bottom which must be multiplied by the conversion factor of 0.2 to obtain the KML. Again using a mean draft of 3.4 meters, we extract a value of approximately 158 from the bottom scale. Multiplied by the conversion factor given of 0.2, this gives us a KML value of 31.6meters. Compare this to the tabulated value for 3.4 meter draft. 9. To find the KMT or vertical distance from the keel to the transverse metacentre we use curve #8. Again we enter the table with the mean draft and follow along horizontally until we cross curve #8. A vertical is then dropped to extract a value from the scale at the bottom which must be multiplied by the conversion factor of 0.02 to obtain the KMT. Again using a mean draft of 3.4 meters we extract a value of approximately 235. Multiplying this by the given conversion factor of 0.02 gives us a KMT of 4.7 meters. Once again compare this to the tabulated value on page 39.

12.2.8 Cross Curves of Stability Immediately following the hydrostatic curves and tables for the same trim condition of the vessel are the Cross Curves of Stability table and curves. These are a set of curves from which the righting levers about an assumed centre of gravity for any angle of heel, at any particular displacement may be found by inspection. The curves are plotted for an assumed KG. The actual KG of the vessel is different from this therefore, a correction must be applied to the righting levers taken from the curves.

Cross Curves • Cross curves are very useful to find righting levers (GZ's) at various angles of heel for a proposed (or actual) load condition, outside those listed (precalculated) in the stabilty booklet.

In the F/V ‘ Skate’ booklet, and in fact for most fishing vessels, the Cross Curves are drawn for an assumed KG of 0.0 ft. or meters. In other words the curves are really KN Curves because they are drawn assuming that the centre of gravity is at the keel level. Refer to the sketch below.

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The Cross Curves of Stability table or graph, for a given level of trim, is entered with the vessel’s displacement and righting levers can be extracted for various angles of heel. In the Skate stability booklet the levers are given for a 0.0 ft. KG so the values extracted are KN values. To find the approximate GZ lever at any of the given angles of heel the following formula would be used: GZ = KN - (KG x Sine of the angle of heel) From the stability booklet for F/V ‘Skate’ on page 41, for trim of zero, if we use a displacement of 310 metric tonnes and a corrected VCG of 3.5 meters, just for illustration purposes, a KN value of 0.800 can be extracted from the table for an angle of heel of 100. Entered into the formula above (GZ = KN – KG (Sin of Angle of Heel), this will then give us a GZ lever of 0.192 meters.

Figure 12.2.8 (A) Location of KN (Source: Ship Stability for Masters and Mates, C.B. Barrass and D.R. Derrett

F/V ‘Skate’ Pages 41 and 42

GZ = KN - KG (Sin 10º) GZ = 0.800 - 3.5 (0.17365) GZ = 0.800 - 0.608 GZ = 0.192 meters

Figure 12.2.8 (B) F/V ‘Skate’ stability booklet. Page 41. Cross Curves of Stability Tables for zero trim

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Chapter 12 | Interpreting Stability Booklet Data

Cross curves of stability can be used to get a snap shot of a vessel’s stability characteristics very quickly, simply be entering the table or curves with a displacement and assuming various heel angles. Cross curves are used when the vessel's condition or proposed condition of load is outside one of the pre-calculated conditions in the stability booklet. By using the cross curves we can construct our own GZ curve for any condition of load.

Example Showing Use of Cross Curves (KN) Righting Lever (GZ) = KN - (VCG × sinθ) Where KN = Cross Curve Value at Displacement of Interest VCG

= Centre of Gravity of the Ship Above Baseline Corrected for Free Surface Effects

= Angle of Inclination

Displacement = 310MT / Corrected VCG (KG) = 3.5 meters / Trim = zero θº

SIN θº

KG x SIN θº

GZ = KN - (KG x SIN θº)

0.401

3.5

0.0872

0.305

0.096 meters

0.800

3.5

0.1736

0.6078

0.1922 meters

1.560

3.5

0.342

1.1971

0.3629 meters

2.170

3.5

0.5

1.750

0.420 meters

2.653

3.5

0.6428

2.250

0.403 meters

3.062

3.5

0.766

2.681

0.381 meters

3.417

3.5

0.866

3.031

0.386 meters

Enter the Cross Curves of Stability at the trim closest to the trim of the condition you are analyzing. At the calculated displacement, read the righting arm values (KN) at the angles noted in the table. Perform the calculations as noted in table. For more precise results, interpolation may be necessary if the trim level is between two sets of Cross Curve data or similarly if the calculated displacement falls between two tabulated levels of displacement. The VCG value shall be corrected for free surface as shown in the previous example. The GZ value is then plotted against the angles of inclination to obtain a righting lever curve from which the Master can determine the vessel's stability. The vessel must meet the Stab 4 Criteria as outlined on the Trim and Stability Conditions. FVSS Sections 4.186 to 4.194

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12.2.9 Maximum VCG or KG vs. Displacement Tables and Curves “The curve of Maximum VCG is a useful tool for quickly determining whether a certain loading condition will meet the intact stability criteria. The curve is prepared by analyzing the ship at a range of displacements. At each displacement, the centre of gravity (VCG) is raised until one of the stability criterions is not met. At this point, the margin of stability is zero and a value of the curve is obtained. In order for a condition to pass the required stability criteria, the ship’s centre of gravity, after it has been corrected for free surface, must be less than the limiting VCG.

F/V ‘Skate’ Pages 55 – 57.

Maximum VCG Values

If the curves of Maximum VCG were not used, the second option for the Master would be to calculate the righting arm curve for the condition using the Cross Curves of Stability.”

• Curve or table of maximum VCG values are used to tell if a proposed or actual load condition meets Stability 4 limits.

If the Master can calculate the position of the vessel’s centre of gravity, (i.e. VCG or KG) corrected for free surface effect,” then by entering the Maximum VCG tables or by plotting that value on the Maximum VCG curve against the vessel’s current displacement, a quick inspection can determine whether the current condition is within safe limits as defined by the Stab 4 criteria.

• The VCG's listed are the maximum height that G can be raised at that displacement and still be safely within the six STAB 4 limits.

Obviously if the vessel is loaded to match one of the pre-calculated conditions in the stability booklet then, by quick inspection of that condition, the Master can easily determine if the vessel is within standard regulatory safety limits. Often however, the vessel will not be loaded to match any of the pre-calculated conditions. To determine its status the Master must do a loading calculation himself, as will be discussed in section 12.3. Upon completion of this calculation the position of the vessel’s corrected VCG will be known as will as the vessel’s total displacement in this condition. If these two values are taken and entered into the appropriate Maximum VCG table or curve, for the vessel’s current trim, it will be apparent if it falls within the safety limits prescribed. For a given displacement and in the prescribed state of trim, if the corrected VCG is less than that in the table or if it is below the Maximum VCG Curve then the vessel’s stability condition is within the prescribed regulatory limits. If, however, the vessel’s corrected VCG exceeds the limiting Maximum VCG from the table or is above the Maximum VCG Curve, then the vessel’s stability does not meet statutory requirements. The position of the vessel’s centre of gravity must be lowered by moving weights lower down in the vessel or filling tanks situated low down in the vessel. Pressing up slack tanks will also help by reducing the free surface effect. As can be seen in the table on the next page as taken out of the F/V ‘Skate’ stability booklet, this particular table is compiled for the vessel at zero trim. There are other tables in the booklet for different levels of trim. The far left column is entered with the current displacement of the vessel in metric tonnes. The next column, the Maximum VCG, in meters, for this displacement is listed.

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If the vessel’s corrected VCG is less than the tabulated value then the current condition of load is within the statutory safety limits. If, however the corrected VCG is higher than that extracted from the table, then you are outside those safety margins and corrective measures must be undertaken immediately. The same information and conclusions can be gathered by examining information extracted out of the Maximum VCG Curves.

Figure 12.2.9 Page 55 of F/V ‘Skate’ stability booklet:

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Chapter 12 | Interpreting Stability Booklet Data

In most instances the above is all that is required with regard to VCG Curves and Tables. However, note that in the above table there is a list of percentages labeled LIM 1 to 6, for each displacement. These percentages indicate by what percentage that the vessel in this condition of trim, and at that displacement and with the listed VCG, exceeds the prescribed regulatory stability limits of Stab 4. For example the following information is given for the vessel with zero trim at a displacement of 330 metric tonnes: • Max VCG

3.800 meters (This is the maximum height of G to remain within reg. limits)

• LIM 1 122%% (At this displacement and VCG, the GM is still 122% over Stab 4 limits) • LIM 2

63% (Area under GZ curve from 0° to 30°exceeds min. required by 63%)

• LIM 3

42% (Area under GZ curve from 0°to 40°exceeds min. required by 42%)

• LIM 4

27% (Area under GZ curve from 30°to 40°exceeds min. required by 27%)

• LIM 5 0d( The angle from 0° to the maximum righting angle is 25º. As indicated, the minimum required is exceeded by 0° • LIM 6 26% (The righting arm (GZ) is 26% longer than the Stab 4 minimum required at 25º of heel or Max RA.) Since these are Maximum VCG values that the vessel can have with corresponding displacements and still meet all of the minimum Stab 4 requirements, then for each tabulated list of values from LIM 1 to LIM 6, for a given displacement, a minimum standard was reached, whether that was Limit 5, the angle from equilibrium to the angle of maximum GZ lever, as in this example, or some one of the other Stab 4 limits. (The standard GHS computer software program that is used to produce the stability booklets will actually run the Max VCG calculations as a loop until the margins for all the limit statements are either positive or zero.) Remember that if the curves of Maximum VCG were not used, the second option for the Master would be to calculate the righting arm curve for the condition using the Cross Curves of Stability. This would involve converting the different KN values to GZ values by the formula GZ = KN - KG sin B. It would take a little longer but it would provide some more accurate information specific to the calculated displacement and VCG. FVSS Sections 4.195 to 4.208

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12.3 Current Condition vs. Pre-Calculated Condition 12.3.1 Construct a displacement table (loading sheet) To determine the stability characteristics of a vessel for conditions other than those included in the stability booklet we follow the following procedure: 1. Determine the weight and centres of all loads. Vertical centres are required above baseline as indicated on the Baseline Particulars and the longitudinal centres are from amidships; 2. Sum the weight and the products of the weights by their centres. The results of dividing the sum of the moments by total weight will give the VCG or LCG of the loading condition; 3. Determine the total free surface moment. Free surface moments for fuel and water are given in the Tank Status tables and the Tank Characteristics Tables. Divide this total by the displacement. This figure is known as the Virtual Rise in KG or “The Free Surface Effect” and must be added to the VCG calculated in Step 2, to give the correct KG or KGF for stability purposes; 4. For quick reference in determining acceptable loading conditions (without topside ice) a Maximum VCG curve is used. For the displacement you have calculated, read the curve at the correct trim to determine the maximum permissible KG. As long as the KGF calculated in Step 3 is less than the figure from the curve then the loading condition is acceptable; 5. To determine righting areas under curves etc., it will be necessary to use the “Cross Curves of Stability” for the correct trim.

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Sample loading sheets are included in all stability booklets to guide the Master as to how to do stability calculations for the vessel in a very straight forward and easily understood manner. The sample from Fishing vessel `Skate is listed below:

Figure 12.3.1 (A) Taken from page 11 of F/V 'Skate' stability booklet

Note on Weight Creep It is important to always bear in mind the potential negative effects of ‘weight creep’ on the stability of a fishing vessel. This considerable addition of weight over time can have a substantial effect on the vessel’s stability and it is difficult to include into a displacement table. It is certainly not included in the pre-calculated conditions. Some examples of items that might contribute to weight creep are: spare parts, spare fishing gear, spare hardware such as blocks, rope, cables, trawl bridles, etc... 12-26

Chapter 12 | Interpreting Stability Booklet Data

Figure 12.3.1 (B) Specimen Condition Sheet for Inclusion in the Stability Booklet. Taken from http:// www.tc.gc.ca/acts-regulations/GENERAL/C/csa/regulations/070/csa75.html#KA

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12.4 Taking Corrective Action 12.4.1 Procedures to prevent or rectify dangerous situations The proper corrective action to take in order to restore the vessel to a state of stability within acceptable safe margins has been discussed throughout this course. It is impossible to clearly define the right specific action to take for any particular vessel or circumstance. In general, if the centre of gravity is beyond the standard safety margins then it must be lowered. Examples of ways to achieve this might be: – Move weights from higher positions on the vessel down lower. An example might be to lower any booms down to the deck or to put heavy fishing gear into the fish hold, depending on the situation; – Transfer fuel from half full tanks to top up others, preferably lower tanks which will both lower the centre of gravity and reduce the free surface effect; – Ensure that all fish in the hold is adequately penned; – There have been circumstances where the Master has had little choice but to ‘get rid’ of his fishing gear on deck in order to ensure the safety of the vessel. This could mean running out the trawl and doors, setting out the seine, or setting out crab or lobster pots. Gear set out in a hurry can usually be buoyed off and retrieved later after the weather clears or the vessel is off loaded; – Removal of accumulated ice on a fishing vessel, especially on high up riggings and superstructure is crucial to the safety and survival of the vessel. Ice must be removed properly with due consideration to the potentially dangerous consequences associated with an angle of loll.

12.5 Ullage Tables 12.5.1 Interpret data found in the ullage tables Many vessels have been furnished with a set of ullage tables along with their stability booklets. These tables are designed so that the Master can determine the approximate weight of fish in particular pelagic species that is aboard the vessel at any given time. The tables usually come with clear instructions as to their use and where the ullage is supposed to be measured. To determine the weight of fish on board, the ‘ullage’ or distance from the surface of the fish to the top of the hatch coamings is measured using a ‘dipping rod’. This measurement is then used to enter the ullage table and extract the weight of fish on board. The instructions usually state the intended trim of the vessel as well as specify that they are assuming no heel. Different tables are often included for mackerel, herring and capelin due to their different stowage factors.

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Chapter 12 | Interpreting Stability Booklet Data

An example of an ullage calculation might be:

Given the above information extracted from a vessels ullage table, if the ullage measurement was 7 ft. 2 in. then the estimated weight aboard of capelin would be 45.23 MT or about 2205 x 45.23 = 99,732 lb. One major limitation of using ullage tables is that they are only accurate if the vesselâ&#x20AC;&#x2122;s fish hold is loaded uniformly. If the pens are loaded at different levels, which is often the case, then an ullage measurement and weight estimate is very limited in its accuracy.

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ÂŠ Marine Institute of Memorial University

Chapter 13 Effect of Fishing Operations on Vessel Stability

Chapter 13 | Effect of Fishing Operations on Vessel Stability

13.1 The Effect of Handling Fishing Gear on Stability 13.1.1 Active fishing gear Whether a vessel is fishing with active or passive fishing gear the basic stability and seamanship considerations are the same. The effects of added weight at a high point in the vessel, shifting fish or fishing gear, effects of pulling from a high point of suspension, free surface effect, maintaining adequate freeing arrangements on deck, downflooding, and maintenance of adequate freeboard for the prevailing circumstances are the major concerns. Each of these factors must be considered together because it is nearly always a combination of factors that cause a fishing vessel to capsize. Active fishing gear is gear that is designed to be physically moved in order to catch fish. Examples of active fishing gear include purse seines, otter trawls, beam trawls, scallop dredges and Danish seines. While it is certainly beyond the scope of this course to explore the method of operation of different types of fishing gear, suffice it to say that from a ship’s stability perspective, many types of fishing gear raise common stability concerns. All of the above types of fishing gear use technology that, by their nature, require either towing from a relatively high point or pulling from a high point in the vessel. Some practical considerations are: • When a vessel is towing a trawl or a drag, it usually does so from the hanging trawl blocks in the A frame or gallows. The entire weight associated with the torque produced by the vessel and the resistance created by the fishing gear, as well as possible shock loads, is centered at the center of the trawl block on each side. This obviously raises the centre of gravity of the vessel considerably but because the added weight is on both sides, then during normal operations one cancels out the other. However, the following must be considered:

– If one warp were to break then this would cause a tremendous uneven moment to be exerted on the opposite side which, when coupled with the right sea conditions, may be enough to cause the vessel to capsize.

– If the fishing gear were to become fast upon an obstruction then the amount of torque that might be exerted to break the gear free could be substantial. There is a danger of the vessel becoming swamped from on coming seas as well as one of the warps breaking from the extra strain and the vessel suddenly capsizing. In addition, the danger of structural failure aboard the vessel or recoil from parting gear, resulting in severe or fatal injury must be constantly borne in mind.

• When a vessel is engaged in purse seining operations it is standard to use either a power block to retrieve the seine, as is normally the case on the East Coast or to use a large drum to retrieve and store the seine as is common in B.C.

– When using a power block it is important to bear in mind the amount of torque that this piece of equipment can produce. For example a small 19” power block could have a line pull of about 4000 lb whereas a larger 36” block may be rated at around 12,000 lb. line pull depending on the hydraulic configuration. From a stability perspective the force that is exerted at the head of that boom will raise the centre of gravity of the vessel considerably. It will also exert a considerable

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listing moment toward the side in which the seine is being handled, especially when a large volume of fish is caught. This listing moment will both cause the vessel to heel and to ‘want’ to heel further. Seiners usually pump or brail in large volumes of fish rapidly. It is imperative that this fish be properly penned as it is brought on board. Many incidents have occurred when vessels have capsized in a partially loaded state while purse seining and many more near misses go unreported. Seines piled on deck may shift toward the low side as well (if the vessel is listed) which will compound the problem and be hazardous for crew.

– Vessels fitted for purse seining using drums to stow and handle their seines also raise areas of concern from a stability perspective. The weight of the net drum with the seine on it is substantial, with its centre of gravity well above the deck. As the seine is retrieved it obviously wraps larger and larger onto the drum raising the ‘pulling point’ higher as the seine comes on board. These drums are geared up to be very powerful so as the weight of fish comes progressively more and more, the forces are considerable.

– When fish is being ‘dried up’ at the end of the set for loading, sometimes overhead booms are used which can also have a negative effect on the vessel’s stability. Hydraulic ‘rail rollers’ are the preferred method because the weight associated with the drying up operation is transferred from the power block to the vessel’s rail, which is much lower.

– The importance of the adequate penning of all fish, especially pelagic species as well as a good awareness of the dangers of free surface effect of fish cannot be over stressed.

• All watertight doors should be kept closed at all times as well as hatch covers securely dogged tight to guard against downflooding should there be a sudden and catastrophic event while fishing.

13.1.2 Passive Fishing Gear Passive fishing gear is gear that is usually set stationary to catch fish. One definition to differentiate active from passive gear would be to say that with active gear the fish harvester must actively pursue the fish whereas with passive gear the fish comes to the harvester (not necessarily voluntarily). Examples of some types of passive fishing gear would be:

Passive Gear • Passive gear - set stationary to catch fish. • Active gear - gear that must be physically mould to catch fish.

– Long lines – Gillnets – Entangling nets – Drift nets – Crab, lobster, cod, shrimp, etc... pots – Capelin, cod, mackerel and squid traps

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Chapter 13 | Effect of Fishing Operations on Vessel Stability

From a ship’s stability and general safety perspective the following are considerations with regard to passive fishing gear: – A vessel fully laden with gear such as crab pots, lobster pots or nets has a considerable weight added usually at the deck level and above. This invariably raises the vessel’s centre of gravity. The Master should always do a pre-loading calculation to determine if the planned loading arrangement is within prescribed limits as discussed in Chapter 12. – Vessels loaded with gear on deck are often ‘lumbered up’ to the point that it would be very difficult to set out the gear in an expeditious manner should an emergency arise and warrant such action. – When loading gear on deck it is important to ensure that all of the freeing ports are intact to ensure the free flow of water from the vessel’s deck. Another consideration is the free movement of rope and nets on deck which may be washed out through the freeing port and entangle the propeller leaving the vessel disabled. – Small open vessels fully laden with gear such as lobster pots are particularly vulnerable to swamping or capsizing. – The retrieval of fishing gear such as crab pots or gill nets in general does not pose as serious a threat to the vessel’s stability as does mobile gear. However there was at least one recent incident where the strain from hauling gill nets was the final factor that contributed to the capsizing of the vessel. Most capsizings occur due to a combination of factors and the line pull from ‘fixed’ gear that has possibly hooked bottom may just be the final catalyst. – All watertight doors should be kept closed at all times as well as hatch covers securely dogged tight to guard against downflooding should there be a sudden and catastrophic event while fishing.

FVSS Sections 5.014 to 5.019

13.1.3 Fishing operations - shifting loads (13.1.3.- 13.1.7 Source: A Guide to Fishing Vessel Stability, Society of Naval Architects and Marine Engineers, U.S) When the sudden shifting of a fishing vessel’s catch or heavy fishing gear occurs during the voyage, its overall stability is reduced because:

Figure 13.1.3 Negative Effect of Shifting Loads

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Chapter 13 | Effect of Fishing Operations on Vessel Stability

– The shifting of the fishing vessel’s catch or gear creates a “permanent” list, reducing its overall stability levels – The vessel’s centre of gravity “G” is shifted farther outboard because the catch has fallen to the low (outboard) side. – The vessel will not return to the upright condition due to the permanent shift in the catch’s centre of gravity. It lies over or “lolls” about the angle of heel where the righting arm curve is zero.

Recommendations: Secure all catch to prevent shifting. Also secure all fishing gear and other heavy items when not in use to prevent their unintended movement.

13.1.4 Fishing operations - lifting weights Lifting weights can significantly reduce a fishing vessel’s overall stability without the crew being aware of the danger they are facing. Until the weight clears the deck the vessel’s stability levels remain the same. However, the instant the weight clears the deck its effective centre of gravity shifts to the tip of the boom, immediately raising the vessel’s centre of gravity. In addition, if the weight is free to swing, the dynamic swinging of the weight temporarily shifts the vessel’s centre of gravity outboard, further reducing its stability. The vessel’s overall stability has been reduced because:

Figure 13.1.4 Negative Effect of Lifting Weights

– The vessel’s centre of gravity “G” is raised due to the lifted weight’s effective centre of gravity being transferred to the boom’s tip. – The vessel’s centre of gravity “G” is shifted outboard from the lifted weight’s swinging. – When lifting very heavy weights the vessel may lay over or “loll” about the angle of heel where the righting arm curve is zero. 13-6

Chapter 13 | Effect of Fishing Operations on Vessel Stability

– Lifting weights on board a fishing vessel results in a significant rise in the centre of gravity “G” which reduces its overall stability. Additional reductions in the overall stability can result from the load being able to swing freely.

Recommendations: Never lift more weight than recommended in the vessel’s stability guidance. Minimize the time when lifting and secure the load with pen boards or ropes to prevent its swinging. If seas are moderate to large, suspend all lifting operations and secure all the fishing gear and catch to prevent its shifting.

13.1.5 Lifting weights over the side Lifting heavy fishing gear over the side significantly reduces the overall stability of a fishing vessel. In addition to the rise in the vessel’s centre of gravity “G” from simply lifting the weight, the outboard location of the weight directly adds a heeling force, creating a temporary list which further reduces its stability. And if the lifted weight is free to swing, the dynamic swinging of the weight will temporarily shift the vessels centre of gravity outboard, further reducing its stability. The vessel’s overall stability is reduced because:

Figure 13.1.5 Negative Effect of Lifting Weights Over the Side

– Lifting weights over the side of a fishing vessel adds a capsizing force to other possible stability reductions. – The vessel’s centre of gravity “G” is raised due to the lifted weight’s effective centre of gravity being transferred to the boom’s tip. – The vessel’s centre of gravity “G” is shifted outboard when the boom and lifted weight are moved over the vessel’s side. – The outboard location of the fishing gear being lifted creates a direct capsizing force and generates a temporary list. Fishing Master Program, Ship Construction and Stability Book I

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Chapter 13 | Effect of Fishing Operations on Vessel Stability

Recommendations: Never lift more weight than recommended in the vessel’s stability guidance. Minimize the time when lifting fishing gear over the side of the vessel and if possible secure the load to prevent excessive swinging. If seas are moderate to large, suspend all lifting operations and secure all the fishing gear and catch to prevent its shifting.

13.1.6 Fishing operations - towing fishing gear Towing fishing gear can significantly reduce a fishing vessel’s overall stability due to several factors. While each factor may be relatively small, the combined impact is sometimes large, especially in heavy seas and when the fishing gear hangs up.

Figure 13.1.6 Negative Effect of Towing Fishing Gear

– First, the towing loads will act as added weight, which raises the vessel’s effective centre of gravity “G” because the towing point is generally located high on the vessel. – Second, the vessel’s freeboard is reduced, especially in the aft corners, causing the deck edge to submerge at smaller heel angles. – Third, as the vessel responds to passing beam or quartering seas, the towing loads shift side to side on the vessel creating a temporary outboard shift in the vessel’s effective centre of gravity “G”.

Recommendations: Tow directly off the vessel’s stern using the lowest towing point possible. Minimize fishing time when using high towing points. If potentially dangerous wind or waves are present, suspend all fishing operations.

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Chapter 13 | Effect of Fishing Operations on Vessel Stability

13.1.7 Fishing operations - towing fishing gear while turning Towing fishing gear while turning can significantly reduce a fishing vessel’s overall stability due to several factors. As with the previous example, each factor may be small, but the combined impact can be quite large, especially in heavy seas and when the fishing gear hangs up. Towing fishing gear while turning reduces a fishing vessel’s overall stability due to several factors: – First, the towing loads acts as an added weight that raises the vessel’s effective center of gravity “G” because the towing point is located high on the vessel. – Second, the vessel’s freeboard is reduced, especially in the critical aft corners, causing the deck edge to submerge at smaller heel angles. – Third, as the vessel responds to passing beam or quartering seas, the towing loads shift side to side on the vessel creating a temporary outboard shift in the vessel’s effective center of gravity “G”. – Fourth, the rudder creates a heeling force (shown as the red line “Heeling Arm” in the figure), further acting to capsize the vessel. – Fifth, towing fishing gear causes a reduction in a fishing vessel’s overall stability levels by reducing the righting forces and increasing the capsizing forces. Turning while towing adds further capsizing forces which increase the chance of capsizing. – The centre of gravity of the vessel generally rises due to the high towing load point (as for suspended weights). – The vessel may incline transversely if the gear is being towed on the side. When in motion in a seaway, the vessel will not return to the upright. – The load from the gear results in a lower aft freeboard, increase in draft which may contribute to water on deck. This all results in a much smaller curve of statical stability and therefore overall stability is reduced.

Figure 13.1.7 Negative Effect of Towing on Fishing Gear While Turning

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Recommendations: The effects may be reduced by towing directly off the vessel’s stern using the lowest towing point possible. Make wide turns when towing to minimize sideways pull from the gear. Minimize fishing time when using high towing points and if potentially dangerous wind or waves are present, suspend all fishing operations.

Three (3) Purposes of Bulkheads • Subdivisions in case of flooding. • Add transverse strength

13.2 Change of Stability During Voyage

• Fire protection

13.2.1 General stability considerations during the voyage As was discussed in Chapter 12, masters of fishing vessels which have stability data on board have much information at their disposal. Not only do they have several pre-calculated load conditions upon which they can use or modify accordingly, but also they can draw upon both the cross curves of stability data as well as the maximum VCG verses displacement data to better determine the safety of any load condition. At sea the master must be ever vigilant of the consequences of all aspects of the fishing operation on the vessel’s stability as well as the potential effect that progressive and systematic changes occurring on board may have on diminishing stability reserves. Some of these considerations include: – Progressive weight changes associated with on board ice melting, the consumption of fuel, fresh water, use of bait or the accumulation of ice from sea spray, can have a substantial effect on the vessels stability in a relatively slow but cumulative way. For example, a vessel on route to distant fishing grounds with a deck load of gear, may consume enough fuel and fresh water out of low tanks, coupled with the resultant free surface effect, to compromise the vessel’s stability. – In a vessel with low margins of safety by way of reserve stability, ample consideration must be given to the dynamics associated with a vessel at sea. This will be further discussed in Chapter 14, but it is important for the Master to be vigilantly aware of the interconnection between the constantly changing statical stability of his vessel while at sea, as well as those more apparent changes associated with normal fishing operations and their overall effect on the vessel’s ability to maintain positive stability in a seaway.

13.3 Dangers Associated with the Improper Stowage of Fish 13.3.1 Transverse bulkheads: In Chapter 3 the importance of a vessel’s transverse bulkheads was discussed. The main purposes of the bulkheads are: 1. To subdivide the vessel into watertight compartments in case of flooding; 2. To provide transverse strength to the vessel; and 3. To provide an effective fire barrier, especially the engine room bulkhead. 13-10

Chapter 13 | Effect of Fishing Operations on Vessel Stability

One other more obvious purpose of the transverse bulkheads in a fishing vessel is to facilitate the stowage and proper containment of on board fish products. In addition to the three main structural bulkheads, most fishing vessels are fitted with sturdy transverse partitions or partial bulkheads that divide up the fish hold into compartments commonly referred to as ‘pens’ or ‘pounds’. These permanent subdivisions, along with the installation of a full complement of pen boards (usually corrugated aluminum but some vessels still use wooden boards), are very important tools when used properly, for the proper stowage of fish. Penning the fish reduces the possibility of the fish moving to one side causing a bad list. It also reduces the free surface effect that results from the unfettered movement of ‘fluid like’ fish in the hold. The transverse partitions or partial bulkheads restrict the longitudinal movement of the fish in a seaway as well as restrict the movement of fish due to longitudinal trim. Note: Schedule 8 of the Small Fishing Vessel Inspection Regulations outline the requirements and scantlings for pen boards. http://www.tc.gc.ca/acts-regulations/GENERAL/C/csa/ regulations/070/csa075/csa75.html#R9

13.3.2 Pen boards and bulk cargo... (sample FSE calculation) Example of the reduction of free surface effect by using pen boards: Free surface formula from Chapter 9:

Free Surface Effect =

I d 1 × × V d1 n2

Note: This formula is applicable for rectangular tanks (use Meters).

Remember • The breadth of a tank substantially affects the loss of stability due to F.S.E.

L × B3 12

Where:

L is length of the tank

B is the breadth of the tank

V = The ship’s displacement

d = Density of tank fluid

d1 = Density of sea water

n = Number of longitudinal compartments

For a 55 ft. fishing vessel with a hold of dimensions 20ft. x 18 ft. x 6 ft. and a displacement of 80 T assuming capelin in hold with density of 1.001t/m3: Since meters must be used in the free surface formula above we convert the above dimensions: Fish hold dimensions in meters: 6.1m x 5.5m x 1.8m

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Calculate: Free surface without pen boards: L × B3 12 6.1× 5.53 = 12 = 84.57

I d 1 × × V d1 n2 84.57 1.001 1 = × × 80 1.025 12 = 1.032 meters

Free Surface Effect =

Virtual loss of GM without pen boards fitted in the fish hold is or 1.032 m or 3.4 feet.

Calculate: Free surface with pen boards fitted to divide the hold into three longitudinal compartments: L × B3 I= 12 6.1× 5.53 = 12 = 84.57 I d 1 × × V d1 n2 84.57 1.001 1 = × × 80 1.025 32 = 0.115 meters

Free Surface Effect =

Virtual loss of GM with pen boards fitted in the fish hold = 0.115 meters or 0.37 feet. As can be clearly seen from the worked examples above the benefits of using pen boards to reduce the free surface effect is substantial. Although the formula stated is really only applicable for a rectangular shaped tank, it is the comparison of the two scenarios that empathizes the importance of the proper use of pen boards. The breadth of the fish hold is substantial in relation to other tanks on board a vessel and since the cube of the breadth is a function of the second moment of the free surface about the center line, or in other words used to calculate I, then reducing tank width dramatically reduces the virtual loss of G due to free surface. FVSS Section 3.018

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Chapter 13 | Effect of Fishing Operations on Vessel Stability

13.3.3 Dangers of carrying fish on deck, overloading and excessive trim: Throughout this course the dangers of carrying fish on deck, overloading and excessive trim have been discussed within the context of the current topic being considered. To summarize some of the important points: – Fish carried on deck will likely raise a vessel’s centre of gravity, would probably cause the vessel to be overloaded, may block freeing ports which could cause shipped water to be trapped on deck, may produce a free surface moment if their movement is unrestricted and could lead to the loss of the vessel. – An overloaded vessel will have little or no positive freeboard remaining which may cause it to experience deck edge immersion if even slightly heeled. The vessel will have greatly reduced its reserve buoyancy and have little area left under the righting arm curve to contend with the dynamic forces of nature associated with a vessel at sea. Watertight integrity to guard against downflooding is of paramount importance at all times but especially so if the vessel is deeply laden. The dangers associated with this were discussed in detail in Chapter 9.

FVSS Sections 3.021

– A vessel that has excessive trim behaves awkwardly in a seaway and is difficult to control and steer. A vessel that has excessive trim by the bow probably lacks good directional stability characteristics. Although it may turn rather easily and have a relatively small turning circle, it will be more susceptible to broaching especially in a following sea. A vessel that has excessive trim by the stern may be in danger of being swamped in a following sea, it will submerge its deck at much smaller angles of inclination and it will have less reserve buoyancy than if in good trim. Most vessels with excessive stern trim will be less fuel efficient as well.

FVSS Sections 3.014

13.4 Shock Loads on Gear (Source: A Guide to Fishing Vessel Stability, Society of Naval Architects and Marine Engineers, U.S)

13.4.1 Dangers associated with shock loads on fishing gear: When the vessel is operating in her normal mode, the stresses imposed on her gear should be kept within reasonable bounds. For example, when a trawler is trawling, the total drag of the gear is determined by its size and weight. To trawl at a steady speed, the drag is adjusted by adjusting engine power, where 100HP or 75kW provides about 1 tonne of pull. If the same boat was free steaming, the same power would drive her faster, since the gear is not dragging, and the engine power has to balance only the resistance of the boat. An impact load changes this situation drastically and can introduce forces in excess of those the boat and gear were designed for. An example is the case of a vessel running into a brick wall at full speed and being brought to a halt within a short distance as the bow crumbles. If a vessel of 100 tonnes displacement, moving at 10 knots, is brought to rest in two meters, then the forces exerted on her bow is over 600 tonnes.

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Now this is, hopefully, an unlikely situation. The point is that the size of the force that brings the boat to rest is large and depends only on the mass and speed of the boat and the distance she moves after impact. The size of this force is totally out of the operator’s control. The same principle applies in the more realistic situation of a trawler coming fast by her gear. In this case, the vessel runs on until the trawl boards come together and the net closes up and the sag comes out of the warps. All of this absorbs energy, and it takes a great deal more distance than the two meters of the brick wall to bring the boat to a halt. However, the size of the forces in the gear will still depend only on the displacement of boat, speed of boat, and distance to come to rest, none of which are under the operator’s direct control. If a 100 tonne trawler, trawling at 3 knots, comes to rest in 20 meters, there will be about a 5 tonne force applied. The distance that a vessel runs on when snagged depends largely on the depth of water, since there is more sag in the warps in deeper water. The force exerted depends significantly on the vessel’s displacement. A heavy vessel therefore tends to damage gear more than a light vessel, since the light vessel will be brought up short before anything parts, while the heavy vessel runs on and causes more stress in the gear. Also, any given vessel will damage gear more readily in shallow water than in deep, since with less gear out there will be less catenary to straighten and absorb energy. A shock load also represents an increase in displacement, and hence will cause a loss of freeboard. With a side trawler, the load on the end of the boom will also cause a heeling moment which will tend to capsize the vessel. A stern trawler may find her stern being pulled under, particularly in the following sea, with undesirable consequences in way of water on deck, and down any hatches that may be open.

FVSS Sections 5.014

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Chapter 14 Environmental Effects on Stability - The Dynamics

Chapter 14 | Environmental Effects on Stability - The Dynamics

14.1 Stability Warning Signs and Precautions - Summary and Review 14.1.1 Summary of practical precautions from Transport Canada - Review The information below was taken from the Transport Canada web site at: http://www.tc.gc.ca/ marinesafety/Tp/tp14070/11-vessel-stability.htm Of all accident types, foundering and capsizes caused by a loss of stability are the most likely to lead to a fatality on the water. Many of these accidents could have been avoided if operators took the necessary precautions and observed the warning signs. A well-designed vessel will resist capsizing or foundering in severe conditions if it is operated properly. To reduce the likelihood of these incidents, keep these rules in mind: – Be aware of external forces - wind, waves, and water depth. Always check the weather forecast before departure. Avoid rough weather conditions. – Don't overload your vessel. Be aware of the amount of weight added to your vessel and available freeboard. Distribute the passengers and cargo evenly. – Make sure that all cargo is well secured and remains secure during the voyage. Secure cargo below deck if possible. – Partially filled water ballast and fuel tanks contribute to instability. Free surface liquids must be contained so their influence will not upset the balance of your vessel. – Prevent water from entering the interior of your vessel by keeping hatches, doors, and windows closed, as practicable, when underway. Regular maintenance of gaskets and fastening devices will help to ensure watertightness. – Any water shipped on board must be removed as quickly as possible. Scuppers and drains must meet design criteria and be kept in good working order. – Open vessels and those with large well decks may be prone to swamping, which may lead to sinking or capsizing. – Adjust course, speed, or both as practicable to minimize vessel motion, rolling in particular. – Avoid sharp turns or turns at high speed when loss of stability is possible. – Salt water is denser than fresh water. Your draft will increase and your freeboard will be reduced when leaving the sea and entering fresh water.

Stability Warning Signs – Observe the stability and roll of your boat. Make sure the vessel's movement and reaction to sea conditions is normal, steady, and safe. – Check to make sure your boat is visibly stable. It should not be listing to port or starboard or trimmed excessively by the bow or stern.

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– Observe freeboard and check for flooding. A flooded vessel may appear stable when it is in fact not. – Has the cargo shifted? Make sure the load is well secured and remains secure during the voyage. – Make sure that bilge level alarms are operational. Unusual operation of bilge pumps may indicate an excessive amount of water is entering the interior of the vessel. – A combination of prevention efforts and awareness of the warning signs of instability, along with operator knowledge, can accomplish a great deal in reducing the number of boating fatalities caused by instability and capsizing.

14.2 The Effects of Sea Conditions on Stability Vertical Components of Vessel Motion

14.2.1 A vessel's 6 degrees of motion A ship's complex motion in a seaway is a mixture of surge, heave, sway, rolling, pitching and yawing in response to the action of the waves, superimposed onto the vessel's motion ahead and any steady sideways drift it may be making due to the wind. The ship's centre of gravity consequently follows an irregular spiraling path about the vessel's mean track, which affects the speed and control of the ship as well as creating stress in both its structure and the people onboard. (Ship Dynamics for Mariners', I.C. Clark)

Three (3) Vertical Components of Vessel Motion: • Heave • Pitch • Roll

The Three Vertical Components: – Heave describes the vertical, up and down movement of a vessel in a seaway. Vessels of equal mass, with a greater width to length ratio (wider vessels) will tend to heave less due to the fact that the narrower hull bottom has smaller area than the wider one, so it interacts with a smaller mass of water to produce a lower standing wave with a smaller added mass. – Pitch describes the motion of a vessel about her transverse axis (centre of flotation) Pitch causes the forward and aft ends of the vessel to rise and fall repeatedly in a seaway. – Roll describes the motion of a ship about her longitudinal axis which causes the ship to rock from side to side. Rolling is a restorative motion in which the springiness is due to wave action moving the forces of weight and buoyancy out of vertical alignment. As can be seen in the diagram below, this creates a righting moment to return the vessel to the upright, as the vessel rolls from side to side.

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Chapter 14 | Environmental Effects on Stability - The Dynamics

Figure 14.2.1 (A) The diagram shows the response of B as a vessel is rolling while at sea. (Source: Ship Dynamics for Mariners', I.C. Clark)

Note: Heave can create alternating trimming moments that lead to pitching, which is an example of one motion inducing another through 'coupling' and it illustrates the complexity of a ship's response to waves. (Source: Ship Dynamics for Mariners', I.C. Clark)

Figure 14.2.1 (B) The diagram above shows the interaction of forces that cause broaching (Source: Ship Dynamics for Mariners', I.C. Clark)

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The Three Horizontal Components Horizontal Components of Vessel Motion

– Surge describes the 'sliding' longitudinal motion of a ship. This is very apparent in following seas and, when coupled with a strong yawing moment, may cause broaching. Surge is the motion that is very apparent in a vessel tied to a dock with an 'undertow' present.

Three (3) Horizontal Components of Vessel Motion:

– Yaw describes the motion of a ship about her vertical axis. This causes the forward and aft ends of the ship to swing from left to right repeatedly. A vessel's longitudinal trim will have a direct effect on its tendency to yaw in a seaway as will its directional stability characteristics. (i.e. length to beam proportions)

• Surge • Yaw • Sway

– Sway describes the 'sliding' lateral, side-to-side motion of a ship. Sway is readily apparent in a beam sea along with rolling motion. Sway may be amplified depending on the wave length in relation to the shape and size of the vessel. For example a 65' fishing vessel may experience considerable sway in a condition of long broad side swell. FVSS Sections 5.058 to 5.067

Figure 14.2.1 (C) A Ship's Six Freedom's of Motion (Source: Ship Dynamics for Mariners', I.C. Clark)

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Chapter 14 | Environmental Effects on Stability - The Dynamics

14.2.2 Dynamical effects of the sea on GZ curve 'reserve righting energy' As a vessel moves with the sea throughout its six degrees of freedom its waterplane area is constantly changing shape, as indeed is its underwater volume. For this reason the position of B, the centre of buoyancy, is constantly changing. As we have learned throughout this course the force of buoyancy acts vertically upward through B and the force of gravity acts vertically downward through G, creating the lever GZ. Obviously the location of G is constant, but in a seaway, as the vessel reacts to waves, the location of B will vary as the shape of the IMMERSED hull form changes; sometimes resulting in an increase in the righting arm and at other times a reduction (i.e. The movement of the vessel in the seaway will cause dynamic forces (accelerations) to be exerted upon it such that it will not always displace its own weight as per Archimedes' Principle.) Therefore at any given point in time the righting energy that is present to restore the vessel to its upright position varies.

Dynamical Stability GZ Area x ∆ • GZ area from 0 0 up to the angle of heel in question. • ∆ is displacement of the vessel in its current condition of load.

Figure 14.2.2 (A) Illustration of changes to a vessels WPA and underwater volume in a seaway. This particular diagram shows the redistribution of the underwater form of a vessel in waves. (Source: Ship Dynamics for Mariners', I.C. Clark)

The above is a very over simplistic description of the variation in a vessel's stability as it moves in a seaway, but it is adequate to draw attention to the changing dynamical stability requirements of a vessel at sea. It is simply intended to illustrate the importance that a vessel must have sufficient reserve stability in a static or still water sense so that it can safely withstand the dynamical requirements that may be imposed upon it by the forces of nature in the area in which it operates. Fishing Master Program, Ship Construction and Stability Book I

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Dynamical stability by definition is the amount of work done in inclining a vessel. With the concept of dynamical stability we attribute this work to the forces of nature such as wind, sea, tide, etc...(external forces). The measure of dynamical stability is found by the formula GZ Area x ∆ (where GZ area is that area under the GZ curve up to the applicable angle of heel).

Figure 14.2.2 (B) These two GZ curves show what happens in general terms to a vessel's righting energy as she encounters waves. The first curve is the static GZ curve of the vessel in its current condition of load where as the second part of the figure shows the same vessel perched on a wave while at sea. Note the significant reduction in the righting energy; range of stability and certainly in the maximum righting arm. The exact amount of reduction in energy, of course, depends on the hull involved, but this case is typical of many fishing vessels

14.3 Dangers associated with following seas 14.3.1 Following seas - riding down the face of a steep wave Operating in following seas (waves on the stern) when riding down the face of a steep wave can lead to sudden capsizing of the vessel. – First, if the vessel surfs and accelerates down the wave, there is an increased chance of burying the bow in the backside of the preceding wave. This may cause the pilothouse windows to blow out or lead to the vessel broaching and capsize. – Second, because the natural flow of the water in the wave is in the same direction as the vessel, the rudder may lose effectiveness, leading to the loss of steering control. This can cause broaching and possible capsize.

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Recommendations In severe sea conditions, change course to put the bow into the seas. If the vessel must run with the seas, riding on the backside of the preceding wave minimizes the dangers.

Figure 14.3.1 Riding down the face of a steep wave

14.3.2 Following seas - riding on the crest of a steep wave Operating in following seas (waves on the stern) when riding on the crest of a steep wave can significantly reduce a fishing vessel's stability by several actions. – First, the critical stability supplied by the stern of the vessel is severely reduced when the stern is lifted clear of the water and no longer provides any righting forces. – Second, the reduction in the vessel's amidships freeboard further reduces the overall stability levels. This may lead to direct capsize of the vessel. – Lastly, because the stern could be lifted clear of the water, the rudder may lose effectiveness, leading to the loss of steering control. This can lead to the danger of broaching and capsize.

Figure 14.3.2 Negative effect of following seas. Riding on the crest of a steep wave

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Recommendations In severe sea conditions, change course to put the bow into the seas. If the vessel must run with the seas, riding on the backside of the preceding wave minimizes the dangers.

14.3.3 Following seas - riding in the trough of a steep wave Operating in following seas (waves on the stern) when riding in the trough of a steep wave can significantly reduce a fishing vessel's stability without making the crew aware of the danger they are facing. The overall stability is reduced by several actions: â&#x20AC;&#x201C; First, there is an increased chance of burying the bow in the preceding wave's back side. This may cause the pilothouse windows to be blown out or lead to the vessel broaching and capsize. â&#x20AC;&#x201C; Second, there is an increased chance of being swamped by a boarding wave. The added weight of the water on deck raises the vessel's centre of gravity and creates a sizable free surface capsizing force.

Figure 14.3.2 Negative effect of following seas. Riding on the crest of a steep wave

Recommendations In severe sea conditions, change course to put the bow into the seas. If the vessel must run with the seas, riding on the backside of the preceding wave minimizes the dangers.

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14.4 Beam Seas 14.4.1 Operating a fishing vessel in beam seas Operating in beam seas (waves on the vessel's side) can significantly reduce a fishing vessel's stability. – First, there is an increased chance of being swamped by a boarding wave. The added weight of the water on deck raises the centre of gravity and creates a sizable free surface capsizing force. – Second, the wave alters the crucial shifting of the centre of buoyancy "B" to create a capsizing condition. As shown in the left figure below, when the vessel is upright the centre of buoyancy "B" shifts outboard due to the beam wave's shape to create a capsizing force. And when the vessel heels over as shown in the right figure below, which in previous examples creates a positive righting force, it still has a capsizing force present because the beam wave's shape on the hull has prevented the center of buoyancy "B" from shifting outboard. – Third, there is an increased chance of the cargo or fishing gear shifting, leading to a sizable capsizing force. – Fourth, in strong breaking waves the sheer physical force of the breaking wave may capsize the vessel.

Figure 14.4.1 Negative Effect of beam seas

Recommendations In severe sea conditions, change course to put the bow into the seas.

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14.5 Quartering Seas 14.5.1 Operating in a quartering sea Operating in quartering seas (waves on the vessel's stern quarters) is the most dangerous sea condition for a fishing vessel. The effects of the previously discussed following stern and beam seas are combined to significantly reduce a fishing vessel's stability in the following ways: – First, there is an increased chance of being swamped by a boarding wave. The added weight of the water on deck raises the centre of gravity and creates a sizable free surface capsizing force. – Second, the wave alters the crucial shifting of the centre of buoyancy "B" to create a capsizing condition. As shown in section 14.4.1 when the vessel is upright the centre of buoyancy "B" shifts outboard due to the beam wave's shape to create a capsizing force. When the vessel heels over, which in previous examples creates a positive righting force, a capsizing force is still present because the beam wave's shape on the hull has prevented the centre of buoyancy "B" from shifting outboard. – Third, there is an increased chance of the cargo or fishing gear shifting leading to a sizable capsizing force. – Fourth, when riding down into a wave trough the rudder may lose effectiveness, leading to the danger of broaching. Also if the bow is buried in the backside of the leading wave crest, the vessel is in danger of broaching. – Fifth, the sheer physical force of large breaking waves can cause the vessel to broach when riding down the waves face and in the case of extreme conditions directly capsize the vessel.

Recommendations In severe sea conditions, change course to put the bow into the seas.

14.6 Winds on the Beam

Wind Heeling Moments

14.6.1 Operation of a vessel with strong beam winds (heeling force) A strong wind on the fishing vessel's beam can significantly reduce its overall stability without the crew being aware of the danger they are facing. The overall stability is reduced because the righting energy used to resist the beam wind (the red shaded area under the wind heeling arm curve) is no longer available for other forces acting on the fishing vessel such as the waves or the loads from fishing gear. 14-12

• Wind heeling moments are not examined in this introductory course but the effect is simply to reduce the vessels stability by eliminating a portion of the righting energy available under the GZ curve.

Chapter 14 | Environmental Effects on Stability - The Dynamics

Recommendations When in strong winds, head into the seas to remove the heeling forces from the wind. FVSS Sections 5.068 to 5.076

Figure 14.6.1 (A) Negative effect of wind on the beam

Figure 14.6.1 (B) In more complex studies of stability, wind heeling moments can be calculated and reproduced onto a vessel's GZ curve. This is a very complex calculation and its accuracy is very much reliant on a number of variable inputs

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14.7 Icing 14.7.1 Icing conditions F/V ‘Skate’ As a regulatory requirement, fishing vessels that operate during the icing season, in areas where ice accumulation is possible, must meet Pages 63 to 68 Stab 4 stability criteria for icing conditions. This includes on-board ice accumulation on topsides and riggings. The Stab 4 stability criteria for icing conditions differs from the criteria discussed in this manual so far. You will notice in the stability booklet for fishing vessel Skate that two such conditions are included. Note the different Min/Max criteria against which the vessels stability characteristics is evaluated. Operating in icing conditions significantly reduces a fishing vessel's stability from the weight of the accumulating ice because: – The centre of gravity "G" rises rapidly from the added weight high on the vessel. – The freeboard is reduced because of the added weight, which causes the deck edge to submerge at smaller heel angles. These are the same effects that occur when the vessel is overloaded. (A guide to Fishing Vessel Stability, SNAME, U.S)

Figure 14.7.1 Safe loading & negative effect of icing

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Recommendations When icing conditions are encountered immediately take appropriate corrective action in any of the following procedures: – If possible, alter course to return to warmer or protected waters. – Steaming down wind reduces the speed of the ice formation, but use caution if the seas are very strong because stern seas increase the chance of broaching, boarding seas, or burying the bow. – Secure all fishing gear below deck to minimize surfaces that ice can form on. – Keep freeing ports clear of ice to allow rapid draining of water off the decks. – Remove as much ice accumulation as is safe for the current weather conditions. – Maintain radio communication with other vessels and shore side on a regular schedule. – All lifesaving equipment should be broken out and ready for use.

14.7.2 Vessel Icing - Transport Canada Recommendations In the Transport Canada publication "Manual of Safety and Health for Fishermen" (TP 1283E), which is now an archived document, some very appropriate and applicable information was presented as guidance to Masters about operating in conditions that may cause ice formation on the vessel. Most of this information falls under the category of good seamanship practices but the threat of loss of stability and capsizing from icing ties it all together. Most of the relevant points are copied or paraphrased below:

Prior to departure: Firstly the skipper should ensure that the vessel is generally seaworthy, giving full attention to basic requirements such as: 1. Loading within the limits prescribed for the season. 2. Watertightness and weathertightness of the vessel and its fixtures and openings as protection against downflooding. 3. Condition of the freeing ports and operational reliability of their closures. 4. Emergency and life saving appliances and their operational reliability. 5. Operational reliability of all external and internal communication equipment. 6. Condition and operational reliability of bilge and ballast pumping systems. 7. The most critical loading condition against approved stability documents with due regard to fuel and water consumption, distribution of supplies, cargoes and fishing gear, and with allowance for possible ice accretion.

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Chapter 14 | Environmental Effects on Stability - The Dynamics

8. Awareness of the danger in having supplies and fishing gear stored on open weather deck spaces due to their large ice accretion surfaces and high centres of gravity. 9. Ensure that all crew has a complete set of warm clothing and a complete set of hand tools and other appliances for combating ice accretion are School of Fisheries Introduction to Construction and aboard. (I.e. Axes, crowbars, picks, shovels, scrapers, wooden sledge hammers, life lines, safety harnesses and high pressure hoses, etc...) 10. Ensure that the crew is acquainted with the location of means for combating ice accretion, as well as the use of such means, and that drills are carried out so that crew members know their respective duties and have the necessary practical skills to ensure the vessel's endurance under conditions of ice accretion. 11. The Master should acquaint himself with the meteorological conditions in the region of fishing grounds and on route to the place of destination. Study the synoptic maps of this region and weather forecasts; be aware of warm currents in the vicinity of the fishing grounds, of the nearest coastal relief, of the existence of protected bays and of the location of ice fields and their boundaries. 12. The Master should acquaint himself with the timetable of the radio stations transmitting weather forecasts and warnings of the possibility of ice accretion in the destination area.

While at Sea During the voyage and when the vessel is on the fishing grounds, the skipper should keep himself informed on all long range forecast as well as short term periodical forecast. The Master should compare the weather forecast and icing charts with actual meteorological conditions, and should estimate the probability of ice formation and its intensity. Current conditions including wind direction and intensity, air and sea temperatures, sea state, barometric pressure and humidity should be monitored closely. When the danger of ice formation arises, the following measures should be taken without delay: 1. All means of combating ice formation should be ready for use. 2. All fishing operations should be stopped, the fishing gear should be taken on board and placed in the under deck spaces. If this cannot be done all gear should be fastened for storm conditions in its prescribed place. It is particularly dangerous to leave the gear suspended since its surface for ice formation is large and the point of suspension is generally located high. 3. All gear and supplies located on deck, as well as portable mechanisms, should be placed in closed spaces as low as possible and firmly lashed. 4. All cargoes in holds and other compartments should be placed as low as possible and firmly lashed. 5. The booms should be lowered and fastened. 6. Deck machinery, hawser reels and boats should be covered with canvas covers. 7. Life lines should be rigged and fastened on deck.

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Chapter 14 | Environmental Effects on Stability - The Dynamics

8. Freeing ports fitted with covers should be brought into operative condition. All objects near scuppers and freeing ports and preventing water drainage from the deck should be taken away. 9. All cargo and companion hatches, manhole covers, weathertight outside doors in superstructures and deckhouses and portholes should be securely closed to ensure complete weathertightness of the vessel. Access to the weather deck from inner compartments should be allowed only through the superstructure deck. 10. A check should be made of the amount of water ballast on board and whether its location is in accordance with that recommended in the stability booklet. It may be appropriate to fill all empty bottom tanks with sea water to lower the centre of gravity. 11. All fire fighting, emergency and life saving equipment should be ready for use. 12. All drainage systems should be checked for their effectiveness. 13. Deck lighting and searchlights should be checked. 14. Check that all crew are dressed properly before working on deck. 15. Reliable two-way radio communication with both shore stations and other vessels should be established; radio calls should be arranged for set times. The Master should seek to take his vessel away from the dangerous area, keeping in mind that the lee edges of icefields, areas of warm currents and protected coastal areas are a good refuge for the vessel during weather when ice formation occurs. Smaller fishing vessels on the fishing grounds should keep nearer to each other and to larger vessels. The entry of the vessel into an icefield presents certain danger to the hull, especially when there is a high sea swell. The vessel should enter at a right angle to the ice edge, at low speed without inertia. It is less dangerous to enter an icefield bow to the wind. If a vessel must enter an icefield with the wind astern, remember that the edge of the ice is denser on the windward side. It is important to enter the icefield at the point where the floes are the smallest.

During Ice Formation If, in spite of all measures taken, the vessel is unable to leave the dangerous area; all means available for ice removal should be used as long as ice formation continues. Depending on the type of vessel, all or many of the following ways of combating ice formation may be used: 1. Removal of ice by cold water under pressure. 2. Removal of ice with hot water under pressure. 3. Breaking up with crow bars, axes, picks, scrapers, wooden sledge hammers and clearing ice with shovels.

Fishing Master Program, Ship Construction and Stability Book I

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Chapter 14 | Environmental Effects on Stability - The Dynamics

When ice formation begins, the skipper should ensure that recommendations listed below are strictly followed: 1. Establish and maintain radio contact with the nearest vessels. Report ice formation immediately to the ship owner and establish constant radio contact with him. 2. Do not allow ice to accumulate on the vessel. Take immediate steps to remove sludge ice from exposed decks and even the thinnest layer of ice from the vessel's structure. 3. Check constantly the vessel's stability by measuring its roll period during ice formation. If the rolling period increases noticeably, immediately take all possible measures to increase the vessel's stability. 4. Ensure that all crew members working on deck are warmly dressed and wearing a safety line securely attached to the guard rail as well as hard hats to protect against falling ice. 5. Bear in mind the physical risk to the crew both in terms of injury from falling or getting hit with falling ice, frost bite and in particular going overboard. 6. The following should be priority items for ice removal: - Aerials - Running and navigational lights - Freeing ports - Life-saving equipment - Stays, shrouds, masts and all riggings Doors of superstructure and deckhouses - Windlass and hawse holes 7. Remove the ice from large surfaces, beginning with the highest structures because even a small amount of ice on those can drastically reduce stability. 8. When the distribution of ice is not symmetrical and a list develops, the ice must be cleared from the lower side first. Bear in mind that any correction of a list by pumping fuel or water from one tank to another may reduce stability when both tanks are slack. Again be careful...Be sure that it actually is a list and not an angle of loll. 9. Ice must be quickly removed when a considerable amount forms on the bow and a trim develops. One option may be to redistribute water ballast. 10. Clear ice from freeing ports in due time to ensure free drainage of the water from the deck. 11. Check regularly for water accumulation inside the hull. 12. If possible avoid navigating in following seas since this may drastically worsen the vessels stability... 13. Keep a good written record of all actions taken as well as times. Additional information for vessels operating in ice may be obtained from the Canadian Coast Guard publication, 'Ice Navigation in Canadian Waters'. Or on line at http://www.ccg-gcc.gc.ca/ ice-gla/pdf/IceNav_e.PDF.

FVSS Sections 5.078 to 5.101

As a final anecdote it is important to constantly bear in mind that as the owner or owners' representative of a fishing vessel, the Master is ultimately responsible for the safety of his vessel and crew. Many topics were discussed in an introductory form in this course but their importance to the safe operation of a fishing vessel cannot be overstressed. Stability can be and indeed is a very complex subject but its basic principles are relatively straight forward and make common sense. Our decisions should reflect this common sense approach in the day to day operation of our vessels.

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Index

Index A

Bulkheads 2-21,,3-17,,13-10

Active fishing gear 13-3

Buoyancy 5-11,,5-13,,5-16,,6-13

Aft. 1-8,,2-10

Buttock lines 2-4

After peak 2-10 Alarms (on-board) 4-10 Aluminum construction 2-22 Annual self-inspection 4-16 Anti-roll tank 10-8 Archimedes principle 5-3, 8-8, 14-7 B

C Camber 1-7,,1-12 Catamaran 2-9 Centre of buoyancy 5-11,,6-4 Centre of gravity 5-9,,6-4,,6-14,,6-15 Centroid 5-6 Chain locker 2-11

Ballast 2-10,,4-3,,9-19,,12-7

Cleat 2-11

Baseline 1-3,,8-6,,12-9,,12-21

Closed construction 2-9

Batteries 4-9

CO2 systems 4-12

Beam 2-10,,14-11,,14-12

Coefficients of hull form 2-6

Bilge 2-8,, 2-10,,2-11,,4-3

Construction standards 3-4

Bilge keels 10-13

Cross curves of stability 12-21

Bilging 3-19 Body section lines 2-4 Bollard 2-11 Bow thruster 11-8 Bulbous bow 11-6 Brackets 2-11 Breadth 1-6,, 2-4,,6-18,,7-3

Extreme 1-6

Moulded 1-6

D Damage control techniques 3-18 Datum lines 2-4 Deadlights 2-11, 3-10 Deadrise 1-14 Deck 2-11,,2-12,,2-21,,3-5 Deck edge immersion 9-17,,9-14 Deckhouses 2-21

Broaching 8-8,,10-11

Density 8-8, 8-11, 9-10, 12-6, 13-11

Bulkhead 2-11

Depth 1-7

Fishing Master Program, Ship Construction and Stability Book I

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Index

Directional stability 8-7

Freeing ports 3-8, 9-13

Discharges 3-6

Free surface 6 -16,,7-10,,9-3,,9-4

Double chine 2-8

Free surface effect 7-10,,9-12

Downflooding 6-18,,7-3

Free surface moments 12-14,,12-25

Draft 1-8,,1-9,,2-7,,8-6

Fresh water allowance 8-11

Draft marks 1-9, 6-5

FRP (fiber reinforced plastic) 2-24

Dry docking 8-16 Dynamical stability 14-8 E

G Geometric centre 5-11 GM 3 -3,,5-6,,5-14,,5-15

Electrical systems 4-8

Gravity 5-9,,6-5,,12-6,,12-7

Engine seatings (beddings) 2-22

Grounding (electrical) 4-8

Entrance 1-13,,2-11

GRP (glass reinforced plastic) 2-3,,2-24,,2-25,,2-26

Equilibrium

Neutral 6-16

GZ 5 -6,,5-7,,5-14,,5-15

Stable 6-14, 7-23

GZ curve 6 -19,,6-20,,6-21,,6-22

Unstable 6-15 H F

I-4

Halyards 2-11

Fall riggings 2-11

Hard chine 2-8

False keel 2-11

Hatch 2-12, 3-5

Fiberglass construction 2-24

Hatch covers 3-5

Fire dampers 4-11

Hatches 3-5

Fish paravane 10-3

Hawse pipe 2-12

Fishing operations 13-5,,13-6,,13-8,,13-9

Heat sensors 4-10

Flare 1-13

Heave 14-4,,14-5

Floors 2-11

Heel 5-5, 5-14, 6-15, 8-8, 9-12

Following seas 14-8,,14-9,,14-10

Hogging 1-10,,1-11

Forestay 2-11

Hydrogen 4-9

Framing 2-11

Hydrostatic curves 8-10,,12-16

Freeboard 1-10,,6-18,,7-3,,8-12

Hydrostatic tables 8-10, 12-16 ÂŠ Marine Institute of Memorial University

Index

Icing conditions 14-14

Manhole 2-12

Improper ballasting 7-25, 9-19

Margin plate 2-12

Inclining experiment 6-5,,12-4

Mast head 2-12

Initial stability 3-3, 5-6, 6-3, 7-23

MCTC (moment to change trim one centimeter) 8-14,,8-15,,8-16,,12-19

Inlets 3-6

Metacentre 5-14,,6-4,,6-14,,6-15, 8-3, 9-14

Inspections 4 -13

Annual 4-14,

Metacentric arc 5-14, 9-14

Annual self-inspection 4-16

Metacentric height 5-6, 6-3,,6-4, 8-15

First 4 -13

Modifications 11-1,,11-3

Quadrennial 4-15

Random 4-16

Targeted 4-15

Moment 5-7, 6-22, 8-14, 9-9, 11-6 Moment of statical stability 6-22

Keel 2-11,,2-12,,2-21,,6-4

Negative stability 6-15

Keelson 2-12

Notes to the master 3-4, 7-21, 12-5

KN 12-19,,12-20,,12-21,,12-24

Nozzles (propeller) 11-10

Knee 2-12 O L

Open construction 2-10

Length 1-3,,1-4

Origin depth 12-14

Overloading dangers 7-24,,7-25, 13-13

L.O.A. (length over all) 1-3

L.B.P. (length between perpendiculars) 1-4

L.W.L. (load water line) 1-4

Lever 5-7, 6-8, 7-4, 12-21 Lifting weights 13-6,,13-7 List 5-5, 5-8, 6-16 Load displacement 1-16 Load lines 8-12 Longitudinal 1-5,,1-12,,2-11,,2-20

Fishing Master Program, Ship Construction and Stability Book I

P Panting 1-11 Parallel middle body 1-13 Paravanes 10-3 Passive fishing gear 13-4 Pen boards 7-11,,12-6,,13-11 Permeability 3-19 Pillars 2-12

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Index

Pitch 14-4

Planking 2-12

Sacrificial anodes 4-7

Plan view 2-4

Sagging 1-10,,1-11

Plating 2-12

Scantlings 1-11

Portlights 3-5

Scuppers 2-11,,3-8, 9-13,,14-3

Pounding 1-11

Seakindliness 3-3

Positive stability 6-14, 7-23

Seaworthiness 3-1,,3-3

Profile view 2-4,,7-19

Shaft tunnel 2-12

Propeller slip 11-10

Sheer 1-12

Pumping arrangements 4-3, 11-6

Shock loads 13-13

Pumps 4-5

Shore power cords 4-9

Electric 4-5,,4-6

Flomax 4-6

Pacer 4-6,,4-7

Shrouded propellers 11-11 Skylights 3-5 Sonar tubes 3-12 Q

Specific gravity 8-8, 8-11, 9-10, 12-6, 13-11

Quarter 2-12

Sponsons 11-5

Quick closing valves 4-11

Spurling pipe 2-12 Stab 4 criteria 7-22,,12-22

R Racking 1-11 Rail 2-12 Range of stability 6-21,,7-5 Reserve buoyancy 5-16,,6-18,,7-3,,7-12 Roll 6-3,,6-7,,6-10,,10-1, 14-4 Roll factors 6-10 Roll period 10-9 Round bilge 2-8 RSW (refrigerated sea water systems) 7-21,,9-4,,9-10,,9-12, 11-6 Run 1-13

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Stability (defined) iii Stabilizers (outriggers) 10-3 Steel construction 2- 19 Stern 2-17,,8-8,,10-11 Stiff ship 6-3, 7-25, 9-19, 10-9 Storm shutters 3-10 Superstructures 2-21 Surge 14-6 Sway 14-6 T Table of offsets 2-6 Tank characteristics tables 9-10, 12-11

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Index

Tank plans 12-9

Weathertight 2-10,,3-7, 14-15

Tank status tables 12-9

Weight creep 7-26,,9-18, 12-26

Tender ship 6-3, 7-25, 9-19, 10-9

Wet storage 11-6

Thru-hull fittings 3-15,,4-6

Wind heeling moments 10-11, 14-12

Thrusters 11-8 Y

Tonnage Deadweight 1-16

Displacement 1-15

Yard 2-13 Yaw 14-6

Gross 1-14

Net 1-15

TPC (tonnes per centimeter immersion) 5-7,,6-5,,8-8,,8-9 TPI (tonnes per inch immersion) 8-8,,12-16 Transducers 3-14 Transverse 1-5,,2-10,,2-11,,2-20 Transverse bulkheads 2-21, 3-17, 13-10 Trim 5-8,,6-3,,6-5,,7-6, 8-6 Tumblehome 1-13 U Ullage tables 12-28 V Ventilators 3-5 Vinyl ester resins 2-26 W Waterlines 2-4, 2-5 Waterplane area 2-6, 6-21, 8-8, 11-4, 12-18 Watertight 2-10,,3-4,,3-7,,3-11 Watertight integrity 3-4, 3-11, 7-11, 9-14, 13-13 Fishing Master Program, Ship Construction and Stability Book I

I-7

Index

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