Dynamic Positioning - Induction Student Handbook Preview by MI Student Resources

This course pack is made in accordance with Memorial Universityâ&#x20AC;&#x2122;s Fair Dealing Requirements for sale to and use by students enrolled in the course of study for which it was made. This course pack may also include copyright-protected material pursuant to permissions granted by the copyright holder. Any reproduction or other use of this material is strictly forbidden. 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.

ÂŠ Marine Institute School of Maritime Studies 2014

Centre for Marine Simulation Rev. June/2014

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Contents Dynamic Postioning - Induction Course Outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix Chapter 1

Dynamic Positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

DP System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DP Operator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Independent Joystick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Commecial DP Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chapter 2

1-5 1-6 1-6 1-6 1-7 1-7

Dynamic Positioning Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Center of Rotation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Closed Loop Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 The Mathematical Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 Dead Reckoning Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-6 Wind Feed Forward. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 DP Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 DP System Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 DP Capability Plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12 Redundancy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14 Dual Redundancy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 Triple Redundancy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15 Sensor System Data Processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16 Sensor Redundancy in Triple Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17 Sensor Redundancy in Dual Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-18 Sensor Redundancy in Single Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18 Chapter 3 Chapter 4 Chapter 5

Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3 Gyro Compasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4 Other Heading Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4 Heading Sensor and Position Reference Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4 Wind Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 Motion Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7 Other Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 Dynamic Positioning Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 DP Vessel Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 Coordinate Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Position Presentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 Datums. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

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Chapter 6

Position References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Artemis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

Laser Systems CyScan/Fanbeam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Global Navigation Satellite System (GNSS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Global Positioning System(GPS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Differential Global Positioning System (DGPS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultra High Frequency (UHF) Radio Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Medium Frequency (MF)/High Frequency (HF) Radio Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Satellite Link. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Absolute Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Real Time Kinematic (RTK) Technique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Global Navigation Satellite System (GLONASS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Galileo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Relative GPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-10 6-14 6-16 6-16 6-16 6-16 6-16 6-18 6-18 6-18 6-19

Hydroacoustic Position Reference System (HPR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20

HPR Display Control Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transponders/Beacons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Super Short Baseline (SSBL)/Ultra Short Baseline (USBL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Short Baseline (SBL). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long Baseline (LBL). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HPR Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gyro input for HPR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inertial Navigation Systems (INS) & HPR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-22 6-23 6-28 6-30 6-31 6-32 6-34 6-34

Taut Wire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35

Microwave Systems RADius/RadaScan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42

Position Reference System Pooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44

Chapter 7

Thrusters and Manoeuvring Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Propellers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4 Thrusters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-7 Rudders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12 Propulsion System Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14 Thruster Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15 Manual Thruster Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17 Failure Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17

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ÂŠ Marine Institute School of Maritime Studies 2014

Chapter 8 Power Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3 Power Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Management by the DP System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Switchboards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Uninterruptable Power Supply (UPS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single UPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dual UPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8-3 8-5 8-5 8-6 8-7 8-8 8-9

Chapter 9 Dynamic Positioning Modes (DP) Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3 Chapter 10 Planning and Conducting DP Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Planning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Worksite Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3 Environmental Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5 Thrusters and Power Supplies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5 Capability / Redundancy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6 Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7 Position References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7 Operational Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11 Contingency Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12 Checklists. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-13 Initial DP Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-19 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-20 DP Alert Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-20 Worksite Approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21 Worksite Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-22 Conducting Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-23 Worksite Departure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-23 Manning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-24 Watch Handover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-25 Logs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-25 DP Printers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-26 Chapter 11 Guidance and Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 IMO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Administrations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Classification Societies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Industry Organizations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DPO Training Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FMEA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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11-3 11-3 11-3 11-3 11-4 11-4

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Appendix Appendix 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 1-3

GUIDELINES FOR VESSELS WITH DYNAMIC POSITIONING SYSTEMS . . . . . . . . . . . . Appendix 1-3

Appendix 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 2-3

DP Class Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix 2-3

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DYNAMIC POSTIONING - INDUCTION COURSE OUTLINE TYPE AND PURPOSE: This course is designed to provide the student with knowledge and a practical understanding of Dynamic Positioning (DP). The concepts taught will form the basis for further studies in dynamic positioning. CALENDAR ENTRY: Dynamic Positioning, Dynamic Positioning Principles, Dynamic Positioning Applications, Sensors, Coordinate Systems, Position Reference Systems (PRS), Propulsion Systems, Power Systems, Dynamic Positioning Modes, Dynamic Positioning Operations, Documentation, Guidance and Regulation, Practical Operation of a Dynamic Positioning System CERTIFICATE AWARDED: Certificate of Participation* NOTE: This certificate will also include the Nautical Institute logo as well as a student number. Upon course completion, candidates must successfully complete the online examination administered by the Nautical Institute in order to receive the Nautical Institute Logbook. PREREQUISITES: Minimum Requirements will be set at STCW Regulation II/1 - II/2 - II/3 Deck, Regulation III/1 - III/2 - III/3 Engine and III/6 for ETOs. STCW Definition

II/1 Deck

Officers in charge of a navigational watch on ships 500 GRT or more.

II/2 Deck

Master and chef mate on ships 3,000 GRT or more.

II/3 Deck

Officers in charge of a navigational watch and masters of ships of less than 500 GRT.

fficers in charge of an engineering watch in a manned engine room or designated duty III/1 Engine O engineers in a periodically unmanned engine room.

III/2 Engine C hief engineer officers and 2nd engineer officers on ships powered by main propulsion machinery of 3,000 kW propulsion power or more.

III/3 Engine C hief engineer officers and 2nd engineer officers on ships powered by main propulsion machinery of between 750 kW and 3,000 kW propulsion power.

III/6 ETO

Electro â&#x20AC;&#x201C; Technical Officer.

Alternate appropriate Marine Vocational Qualifications will be considered on a case by case basis by the Nautical Institute. Cadets enrolled in a regulated training program may apply for Dynamic Positioning Induction Training but must supply a signed letter from their respective school stating they are currently enrolled and in good academic standing.

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SCHEDULE: Duration:

4.5 days (31.5 hours)

COURSE AIMS: At the end of the course the student should:

Have acquired knowledge of the principles of Dynamic Positioning.

Be able to set up a Dynamic Positioning system.

Have an understanding of the practical operation of associated equipment, including position reference systems.

Be able to recognise and respond to the various alarm, warning and information messages.

5) Be able to relate the Dynamic Positioning installation to the ship system, including (but not limited to); power supply, manoeuvring facility, available position reference systems and nature of work.

6) Be able to relate Dynamic Positioning operations to the existing environmental conditions of wind, sea state, current/tidal stream and vessel movement.

7) Have an understanding of the Nautical Institute Dynamic Positioning Operatorâ&#x20AC;&#x2122;s training scheme, including the requirements for completion of the logbook and the procedure for obtaining a Dynamic Positioning certificate.

MAJOR TOPICS:

1.0 Dynamic Positioning

2.0 Dynamic Positioning Principles

3.0

4.0 Sensors

5.0 Coordinate Systems

6.0 Position Reference Systems (PRS)

7.0 Propulsion Systems

8.0 Power Systems

9.0 Dynamic Positioning Modes

10.0 Dynamic Positioning Operations

11.0 Documentation, Guidance and Regulation

12.0 Practical Operation of a Dynamic Positioning System

Dynamic Positioning Applications

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Course Outline 1.0

Dynamic Positioning 1.1 1.2

2.0

Dynamic Positioning Principles 2.1 2.2 2.3 2.4 2.5

3.0

Dynamic Positioning Systems Dynamic Positioning Training

Position Control Modelling DP Current Redundancy Centres of Rotation

Dynamic Positioning Applications

4.0 Sensors 4.1 4.2 4.3 4.4 5.0

Coordinate Systems 5.1 5.2

6.0

Universal Transverse Mercator (UTM) Datums, Projections and Spheroid

Position Reference Systems (PRS) 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9

7.0

Gyro Compasses Wind Sensors (Anemometers) Motion Sensors Other Sensors

Artemis Differential Global Navigation Satellite System (DGNSS) Frequency Modulated Continuous Wave (FMCW) Radar System Hydro-acoustic Position Reference Systems (HPR) Laser Reference System Taut Wire Other Position Reference Systems Position Reference System Accuracy, Reliability and Pooling Inertial Navigation System (INS)

Propulsion Systems 7.1 7.2 7.3 7.4

Propellers Thrusters Rudders Propulsion System Control

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8.0

Power Systems 8.1 8.2

Power Generation, Distribution and Management Uninterruptable Power Supply

9.0

Dynamic Positioning Modes

10.0

Dynamic Positioning Operations 10.1 Planning 10.2 Conducting Operations 10.3 Communications 10.4 DP Logs 10.5 Checklists 10.6 Watchkeeping Procedures 10.7 Alarms

11.0

Documentation, Guidance and Regulation

12.0

Practical Operation of a Dynamic Positioning System

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Learning Objectives: NOTE: These Learning Objectives are referenced (where applicable) to the Nautical Institute prescribed Aims and Objectives for the Dynamic Positioning Induction course, i.e. (NI#1). These Learning Objectives are also referenced (where applicable) to the tasks in the Nautical Institute Task Book, issued to students on successful completion of the course, i.e. (TB#1.1.1). THE EXPECTED LEARNING OUTCOME, ON COMPLETION OF TRAINING, IS THAT THE STUDENT SHOULD BE ABLE TO: 1.0

Dynamic Positioning

1.1 Dynamic Positioning Systems

– Define Dynamic Positioning (NI#1).

– Explain the need for Dynamic Positioning in various types of vessel (NI#2).

– List the seven main components of a DP system (NI#6, TB#4.1):

a. DP Operator (NI#6)

b. DP Computer (or Controller) ((NI#6, TB#3.2, #4.4)

c. DP Operator Station (NI#6, TB#3.1), Independent Joystick (TB#3.3)

d. Position Reference Systems (NI#6, TB#3.6)

e. Sensors (NI#6, TB#3.7, #4.12, #4.13)

f. Power Supply (NI#6)

g. Thrusters (NI#6, TB#3.5)

1.2 Dynamic Positioning Training

– Understand the Nautical Institute DP training scheme, including the requirements for completion of the logbook and the procedure for obtaining a DP certificate. 2.0

Dynamic Positioning Principles

2.1 Position Control

– Describe the six freedoms of movement of a vessel (NI#3).

– State which of the six freedoms of movement are controlled under DP and which are monitored (NI#4).

– Outline how the components of a DP system achieve control of vessel freedoms of movement.

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2.2 Modelling

– Discuss the concept of mathematical modelling of vessel behaviour characteristics and appreciate the advantages and limitations of this technique (NI#8, TB#7.17).

2.3 DP Current

– Describe the method by which the DP system determines the value for DP current or Sea Force (the residual error resulting from unmeasured errors & unmeasured forces acting on the vessel) (NI#53, TB#9.10, #9.11, #9.4).

– List the reasons for discrepancy between the displayed value of DP current (or Sea Force) on the DP system and the true current or tidal stream value (NI#54).

– State the reasons why a DP system determines DP current.

2.4 Redundancy

– State the purpose of redundancy within a DP system.

– Indicate what types of vessels use different levels of redundancy.

2.5 Centres of Rotation

3.0

– Describe the concept of Centre of Rotation and the provision of Alternative Centres of Rotation (NI#12, TB#7.11).

Dynamic Positioning Applications

– Describe in outline the DP operations conducted by the following vessel types (NI#71):

a. Diving and underwater support vessels. (NI#71.a.)

b. Drill ships & semi-submersible drill rigs. (NI#71.b.)

c. Cable lay & repair vessels. (NI#71.c.)

d. Pipelay vessels. (NI#71.d.)

e. Rockdumping and dredging vessels. (NI#71.e.)

f. Shuttle tanker and FPSO/FSO operations. (NI#71.f.)

g. Flotel (accommodation) vessels. (NI#71.g.)

h. Crane barges and construction vessels. (NI#71.h.)

i. Anchor handling and platform supply vessels. (NI#71.i.)

j. Cruise ships and luxury yachts. (NI#71.j.)

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– Understand that DP is also fitted on the following vessel types:

a. Well stimulation vessels.

b. Crew boats.

c. Survey and seismic survey vessels.

d. Field standby vessels.

e. Buoy tenders.

f. Semi-submersible heavy lift vessels.

g. Naval vessels.

h. Other vessels utilizing DP for specialized operations.

4.0 Sensors

4.1 Gyro Compasses

– Describe gyro compasses as used with DP systems (NI#11, TB#6.1).

– Describe the function of gyro compasses and their redundancy within a DP system (NI#47).

4.2 Wind Sensors (Anemometers)

– Describe wind sensors as used with DP systems (NI#11, TB#4.12, #6.3).

– Describe the provision of wind sensors within the DP system (NI#50).

– Describe the wind Feed-Forward facility and its importance within the DP system (NI#51).

– Recognise the limitations of wind sensor inputs. Explain the reasons for and the consequences of deselecting Wind Sensor inputs (NI#52, TB#9.9).

4.3 Motion Sensors

– Describe the following motion sensor types as used with DP systems (NI#11, TB#4.13, #6.2):

a. Vertical Reference Sensor (VRS)

b. Vertical Reference Unit (VRU)

c. Motion Reference Unit (MRU)

– Describe how to obtain pitch, roll & heave information for input into a DP system (NI#48).

– Describe the reason for inputting pitch, roll & heave into a DP system (NI#49).

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4.4 Other Sensors

– Describe draught sensors as used with DP systems (NI#11, TB#6.4).

– Describe the use of external force reference systems such as hawser tension, plough cable tension and pipe tension monitoring (NI#55, TB#6.4).

5.0

Coordinate Systems

5.1 Universal Transverse Mercator (UTM)

– Describe the Universal Transverse Mercator Coordinate System.

– Explain the use of worksite diagrams using Universal Transverse Mercator coordinates (NI#65).

5.2 Datums, Projections and Spheroids

– Outline the Navigational Projections, Spheroids & Datums that may be used in operations involving Dynamic Positioning (NI#64).

6.0

Position Reference Systems (PRS)

6.1 Artemis (NI#10, TB#4.11, #5.4)

– Describe the principle and operation of the Artemis position reference system (NI#27).

– Outline the setup procedure for an Artemis System.

– List the operational advantages and limitations of the Artemis position reference system (NI#28, TB#9.9).

6.2 Differential Global Navigation Satellite System (DGNSS) (NI#10, TB# 4.11, #5.1, #5.2)

– Describe the principles of the DGNSS system (NI#33)

– Outline the operation of a typical commercial DGNSS network where corrections are delivered by satellite communications (NI#34).

– List the sources of error and inaccuracy associated with the DGNSS system, describing the effects on the quality of positioning (NI#35).

– List the available quality data associated with the DGNSS system (NI#36).

– Outline the setup procedures for a DGNSS System.

– List the advantages and limitations of the DGNSS system when compared with other PRS (NI#37).

– Describe the principles used in Relative DGNSS systems (NI#38).

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6.3 Frequency Modulated Continuous Wave (FMCW) Radar System (NI#10, TB#4.11, #5.5)

– Describe the principles of position reference using FMCW Radar based systems (NI#42).

– Outline the setup procedures for a FMCW Radar System.

– List the advantages and limitations associated with FMCW Radar based PRS (NI#43).

6.4 Hydro-acoustic Position Reference Systems (HPR) (NI#10, TB#4.11, #5.6)

– Describe the operation of HPR systems (NI#22).

– D escribe the principles of position-fixing using underwater acoustic systems working in SSBL/USBL, LBL and SBL modes (NI#23).

– Describe the various types of acoustic beacons: transponder, responder & pinger (NI#24).

– Describe the layout of a typical HPR system including Operator Station, Transceiver, HPR Pole & Transducer (NI#25).

– Outline the setup procedures for an HPR System.

– List the operational advantages and limitations of acoustic systems as a position reference for DP (NI#26).

6.5 Laser Reference System (NI#10, TB#4.11, #5.3)

– Describe the principles of position reference using laser based systems (NI#39).

– Outline the method of setting up a laser system to provide position information (NI#40).

– List the advantages and limitations associated with a laser based PRS (NI#41, TB#9.9).

6.6 Taut Wire (NI#10, TB# 4.11, #5.7)

– Describe the principle of position-reference using the Taut Wire system (NI#31).

– List the different types of Taut Wire position reference systems: vertical lightweight, vertical deep water, vertical moon pool, horizontal and horizontal gangway (NI#29).

– Describe the display of Taut Wire reference data in the DP system (NI#30).

– Have an understanding of the setup and operating procedures for a Taut Wire System.

– List the advantages and limitations of the Taut Wire position reference systems (NI#32).

6.7 Other Position Reference Systems

– Describe other PRS that may be used in conjunction with a DP system (NI#46, TB# 4.11, #5.8).

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6.8 Position Reference System Accuracy, Reliability and Pooling

– Discuss the relative accuracy of the aforementioned PRS (NI#45).

– Discuss the relative reliability of the aforementioned PRS (NI#45).

– Discuss the methods used to apply weighting, pooling and voting when more than one PRS is used (NI#45).

– Identify the different methods of PRS pooling (NI#45).

6.9

Inertial Navigation System (INS)

– Describe the principle of Inertial Navigation and the methods of using INS to enhance existing PRS performance (NI#44).

7.0

Propulsion Systems

7.1 Propellers (TB#4.7)

– Describe fixed and controllable pitch propellers commonly fitted to DP equipped vessels (NI#5 & NI#19).

– D escribe the operational characteristics and common failure modes of fixed and controllable pitch propellers (NI#21).

– D escribe the practical and operational advantages and disadvantages of fixed and controllable pitch propellers (NI#5).

– Describe the effect of fitting propellers with nozzles.

– Describe the practical and operational advantages and disadvantages of nozzles.

7.2 Thrusters

– 7.2.1 Tunnel Thrusters (TB#4.7)

– Describe tunnel thrusters commonly fitted to DP equipped vessels (NI#5 & NI#19).

– Describe the operational characteristics and common failure modes of tunnel thrusters (NI#21).

– Describe the practical and operational advantages and disadvantages of tunnel thrusters (NI#5).

– 7.2.2 Azimuthing Thrusters (TB#4.7)

– Describe azimuth thrusters commonly fitted to DP equipped vessels (NI#5 & NI#19).

– Describe the operational characteristics and common failure modes of azimuth thrusters (NI#21).

– Describe the practical and operational advantages and disadvantages of azimuth thrusters (NI#5).

– Describe pod type thrusters commonly fitted to DP equipped vessels (NI#5 & NI#19).

– Describe the operational characteristics and common failure modes of pod type thrusters (NI#21).

– Describe the practical and operational advantages and disadvantages of pod type thrusters (NI#5).

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– 7.2.3 Jet Type Thrusters (TB#4.7)

– Describe jet type thrusters commonly fitted to DP equipped vessels.

– Describe the practical and operational advantages and disadvantages of jet type thrusters.

– 7.2.4 Cycloidal Thrusters (TB#4.7)

– Describe cycloidal thrusters commonly fitted to DP equipped vessels.

– Describe the practical and operational advantages and disadvantages of cycloidal thrusters.

7.3 Rudders (TB#4.7)

– Describe rudders commonly fitted to DP equipped vessels (NI#19).

– Describe the operational characteristics and common failure modes of rudders (NI#21).

– Describe the practical and operational advantages and disadvantages of rudders.

7.4 Propulsion System Control

– Describe the importance of monitoring the displayed values of Setpoint and Feedback data for thruster and propeller r.p.m., pitch and/or azimuth (NI#20, TB#7.7).

8.0

Power Systems

8.1 Power Generation, Distribution and Management

– Outline the power requirements of a DP vessel system (NI#9).

– Describe the power generation and distribution arrangements in a typical diesel electric DP vessel, with particular reference to system redundancy as described in IMO MSC Circ. 645 and Vessel FMEA (NI#14, TB#4.6, #4.8, #4.9).

– Describe the power supply and distribution arrangements in a typical hybrid diesel/diesel electric DP vessel (NI#15, TB#4.6, #4.8, #4.9).

– Recognise the power requirements of DP vessels and explain the concept of “Available Power” and spinning reserve in worst case failure (NI#16).

– Describe the functions of a Power Management System as installed in a DP vessel (NI#17).

8.2 Uninterruptable Power Supply

– Describe the provision of Uninterruptible Power Supply (UPS) systems to the DP system, with particular reference to power shortages, failures and system redundancy (NI#18, TB#3.4, #4.10).

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9.0

Dynamic Positioning Modes

–

Describe the various modes of DP operation, including (NI#7):

a. Manual control

b. Semi-automatic control (Combined Auto/ Manual)

c. Automatic control (Auto Position)

d. ROV Follow (Follow Sub)

e. Follow Target

f. Track Follow (Auto Track)

g. Minimum Power (Weathervane)

h. Riser Angle Mode

10.0

Dynamic Positioning Operations

10.1 Planning

– Explain the need for planning DP operations, including emergency and contingency situations (NI#66, TB#7.1).

– Understand that planning is to take into consideration the following:

a. Availability of position reference systems (TB#7.10, #8.9).

b. Selection of appropriate heading (TB#7.12, #7.24).

c. Escape route to a safe position in the event of system failure (TB#7.14, #8.6).

d. Assessment of DP system performance and use of power (TB#7.18).

e. Assessment of final working position, drift on or drift off (TB#8.1, #8.2, #9.7).

f. Drift tests (TB#7.19).

g. Awareness of worst case failure (TB#9.12).

h. Capability plots (TB#1.1.3).

10.2 Conducting Operations

– Describe the procedures to be followed when approaching a worksite and transferring from conventional navigation to DP control (NI#56, TB#7.2, #7.4).

– Describe the procedures to be followed when departing a worksite and transferring from DP control to conventional navigation (TB#10.1, #10.2)

– Understand the need to constantly monitor the DP system and carry out continuous risk assessment (TB#9.13)

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– State and describe the hazards associated with DP operations conducted in areas of shallow water and/ or strong tidal conditions (NI#72).

– Describe the hazards associated with DP operations in very deep water (NI#73).

10.3 Communications

– Describe the need for effective communications during the conduct of DP operations (NI#60, TB#7.23).

10.4 DP Logs

– Explain the need for keeping logbook records of all DP operations, failures and incidents (NI#58, TB#1.3.3, #1.3.4).

– Explain the need for keeping records of operation, maintenance and repairs of DP & ancillary equipment (NI#59).

10.5 Checklists

– Discuss the need for completing pre-DP and other checklists prior to and during DP operations (NI#57, TB#1.1.4, #7.21, #8.10).

10.6 Watchkeeping Procedures

– Outline the procedures to be followed by the DPO when taking over the control of the vessel’s positioning and manoeuvring (NI#61, TB#2.5, #2.6).

– Describe watchkeeping arrangements on a DP vessel and be aware of the roles of those who may form part of the DP watch (TB#2.1, #2.2, #2.3, #2.4).

– Understand that a safe navigational watch must be maintained at all times (TB#2.7).

10.7 Alarms

– Describe the alarm messages provided on the DP system displays and on the DP printer (NI#62, TB#11.8).

– Recognise the alarms and warnings associated with loss of redundancy after worst case failure, i.e. part loss of some thrusters or power and catastrophic failure, i.e. loss of heading and/or position control (NI#63).

– Understand the action to take in the event of the following:

a. Degraded status (TB#11.3, #11.12).

b. Failure status (DP system failure) (TB#11.4, #11.10).

c. Drift off (TB#11.6)

d. Drive off (TB#11.7)

e. Reference system failure (TB#11.9)

f. Partial blackout (TB#11.11)

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11.0 Documentation, Guidance and Regulation

– List the various providers of documents containing statutory requirements and guidance relating to DP operations, including (NI#67):

a. IMO (including IMO MSC/Circ. 645 of 1994 Guidelines for Vessels with Dynamic Positioning Systems) (NI#67)

b. Classification Society DP Rules (NI#67)

c. International Marine Contractors Association (IMCA) (NI#67, TB#1.3.5)

d. Marine Technology Society (MTS)

– Explain the purpose of documentation associated with DP operations, such as:

a. DP Operations Manuals (NI#68, TB#1.1.5, #1.3.2)

b. Failure Modes and Effects Analysis (FMEA) (NI#68, TB#1.1.1, #7.22)

c. Capability Plots (NI#68, TB#1.1.3)

d. Annual Trials (TB#1.1.2)

e. System Operator Manuals (TB#1.2.1, #3.8)

f. Charterer, Company or Installation requirements (TB#1.3.1, #1.4.1, #7.25, #7.26)

– Describe the IMO (DP) Equipment Classes and their application, with reference to the IMO Guidelines for Vessels with DP Systems (NI#69).

– U nderstand that Classification Societies use either numbers (eg ABS DPS-2) or letters {eg Lloyd’s Register DP(AA)} to denote the DP Class allocated to the vessel (NI#70).

12.0

Practical Operation of a Dynamic Positioning System

– Understand the need to review system operator manuals, as DP system operating procedures can vary depending on the manufacturer and can also vary as manufacturers develop new products/features.

– Demonstrate the use of the Joystick to manoeuvre the vessel and bring the vessel to a stop in a seamanlike manner (NI#74, TB#7.5).

– Demonstrate the correct procedure for setting-up the DP system in both Manual and Automatic modes (NI#75, TB#7.15, #7.8, #7.9).

– Demonstrate position and heading change manoeuvres, using both automatic and manual DP facilities (NI#76, TB#8.3, #8.4, #8.7, #8.8).

– Demonstrate commonly provided functions on the DP control panel including Gain, Fixed Azimuth mode and Thruster bias (NI#77, TB#7.16, #8.5, #8.7).

– Demonstrate the use of common facilities found on a DP system; e.g. Track Follow, Minimum Power and ROV Follow (NI#78, TB#8.7).

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– Demonstrate setting heading and position warnings and alarms (TB#11.1, #11.2).

– Describe the system switch-on and loading procedure for a DP system used during training, including any reloading procedures necessary (TB#4.5, #4.14).

– Describe Consequence Analysis as carried out by a Dynamic Positioning system (NI#13, TB#11.5).

– Demonstrate monitoring of:

a. Position excursion (TB#9.1,#9.15).

b. Percentage of power in use (TB#9.2, #9.15).

c. Wind speed and direction (TB#9.3).

d. DP current (TB#9.5).

e. Reference system performance (TB#9.8).

f. Thruster performance (TB#9.10.1).

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Chapter 1 DYNAMIC POSITIONING

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Dynamic Positioning Dynamic positioning (DP) is the ability of a vessel to maintain her position and heading automatically, exclusively by means of active thrust. Also defined as the shipboard system which enables this ability. Position, heading and environment reference systems are linked to a DP system computer. The measured vessel position/ heading is compared to the desired position/heading and the computer generates thruster commands to maintain or restore vessel position as required. Commands can also be input to have position or heading changed under DP control. The traditional method of maintaining a vessel at a fixed position is to utilize an anchor pattern. Some DP vessels in fact have the ability to position with anchors if circumstances permit. In some instances the vessel is anchored and the DP system is used in a mooring assist mode. Positioning exclusively by the use of thrusters (DP) is utilized where: Water depth is outside the limits of the vessels mooring system. Sea bed obstructions prevent anchors being deployed or anchoring is prohibited. Type of bottom doesn’t provide good holding ground. The job requires the vessel to carry out movements which are outside the limit of the anchor pattern (anchors have to be repositioned when the vessel is required to move or change heading). »» The presence of anchor lines may prevent the vessel from positioning close to a platform, or may provide obstructions to other vessels. »» Time limitations make mooring less economically viable than DP. The job may take only a short time and anchoring may take hours and require the use of anchor handling vessels. »» Environmental conditions dictate frequent heading changes to keep the vessels bow into the weather. Anchors would limit the ability to change heading unless anchors were recovered and redeployed frequently. »» »» »» »»

In the early 1960’s, DP was a new concept in the petroleum industry. After over 50 years it is a well known and developed technology and has been installed on a great number of vessels. The majority of DP vessels work in the offshore oil and gas industry. The types of vessels fitted with DP systems and the work that they perform are outlined in chapter 4 of this manual.

1961

The first vessel to use thrusters to keep position without the help of any mooring system was the coring vessel Cuss 1. The vessel was equipped with 4 manually controlled steerable thrusters. Position reference was provided by radar echoes from 4 buoys and a sonar interrogated subsea beacon. Five corings were done in 3560 m of water with the vessel remaining within a 180 m radius circle. Simultaneous manual control of thrusters was a difficult and tedious task, so the idea developed to perform the task with a computer. In the same year the coring vessel Eureka fitted with two steerable thrusters and an analog computer to control them was launched. Position reference was provided by a taut wire and mooring operations were conducted in more than 1300 m of water, with 6 m waves and 40 knot winds. DP vessels have evolved from this beginning to encompass all the vessel types outlined in chapter 4.

1970 Drillship Glomar Challenger conducted operations in 3062m of water while on DP.

1971 The exploratory drillship Sedco 445 started the use of dynamic positioning for oil drilling in deep water. © Marine Institute School of Maritime Studies 2014

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1972

The first saturation dive was undertaken from a DP equipped vessel, the drillship Pelican. The operation occurred in the North Sea. Two divers left their bell without the security of conventional anchoring for their support vessel.

1974

The DP equipped Glomar Explorer is used to recover a Soviet submarine from 4800+ m of water. This was the first vessel to use long baseline acoustic positioning.

1975

The DSV Arctic Surveyor enters service. It is the first purpose built DP vessel, specifically designed for saturation diving, sub-sea construction and inspection work.

1976

The first DP semi-submersible drilling unit, Sedco 709, enters service.

1981

The first DP systems are fitted on shuttle tankers. One of the first is the Wilnora operating in the North Sea.

1983 In September 1983, the Nautical Institutes DP training scheme was adopted as an internationally accepted standard for any DSV or other DP-operated vessel working within any designated 500 meter zone at any offshore installation by 105 out of 110 oil industry and major oil company representatives at a working conference in Aberdeen. It was rapidly recognized by the oil Industry on a worldwide basis. Less than a month after the Aberdeen conference, the scheme was accepted as an official guideline by the then Minister of Energy for the UK North Sea operations. Shortly after, it was also adopted by other North Sea operating flag states.

1986

The worldâ&#x20AC;&#x2122;s first DP pipelay barge, named the Lorelay, enters service. The DP equipped Petrojarl 1 enters operation. It is the first purpose built FPSO.

1987

The first flotel with a fully redundant DP system, Polyconfidence, enters service.

1996

Grandeur of the Seas is the first cruise ship fitted with a DP system.

1998 Marine Institute becomes 1 of 5 centres accredited by the Nautical Institute. It offers DP Induction and Simulation Courses.

1999 Worlds 1st satellite launch at sea is conducted from the DP equipped semi-submersible launch platform Odyssey.

2002 The DP equipped drillship Discover Spirit completes an exploration well a world record water depth (for oil exploration) of 2,965m. A total of nineteen centres are now accredited by Nautical Institute to offer DP courses.

2009 A total of 51 centres are now accredited by the National Institute to offer DP courses. 1-4

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2011

The DP equipped drillship Dhirubhai Deepwater KG2 completes exploration well at a world record water depth (for oil exploration) of 3,107m. A total of 64 centres are now accredited by the National Institute to offer DP courses.

2013

The DP equipped drillship Dhirubhai Deepwater KG2 completes exploration well at a world record water depth of 3,165m, breaking its own previously set record.

2014 A total of 69 centres are now accredited by the National Institute to offer DP courses.

DP System A DP system consists of 7 hardware elements plus the DP Operator. The 7 elements are:

(1) The DP Console The DP console is sometimes referred to as the “HMI” (Human-Machine Interface). It is also sometimes called the “DP Desk” or “DP Operator Station”. It is the collection of panels and screens allowing the DPO full control of all DP functions, and displaying all information as to the status of the vessel and system. The control console is where all maneuvering control of the vessel is carried out when using DP. System parameters can be input or altered as required utilizing controls on the DP desk. Newer DP systems rely on a windows operating system where most operational functions can be accessed via a touch screen, on screen via a mouse or a keyboard. Older DP systems rely only on buttons on a keyboard to control the system functions. he control console is usually located on the bridge and should be located so as to provide the DPO a view of the T DP operation from the console position. The console may face aft, forward or sideways and an outside view of the DP operation is not always available. On a few vessels the console is located away from the bridge and has no outside view at all. Video cameras are often utilized to provide the DPOs with a better outside view. Each DP console is fitted with a joystick. Selecting joystick or manual control on the DP console gives the DPO control of all the propulsion units on the vessel, from the single joystick. The joystick can be used to control both the heading and position of the vessel. In some cases the joystick cannot control heading and a separate manual heading control knob is provided on the console.

(2) DP Computers/Processors The DP computers/processors are the main control element. They process information from the various elements of the DP system and output commands to the vessels thrusters to control vessel heading and position. The control computers may be an integral part of the DP consoles or they may be fitted separate from the DP consoles. The number fitted will depend on the required level of equipment redundancy needed for the vessel. DP Control System is a collective term including all processors/computers within the DP system, also including the DP console and any remotely located or backup units.

(3) Position Reference Systems A position reference system (PRS) is any of the numerous navigational systems providing positional feedback for use within the DP system Position reference systems are utilized to provide the DP computers/processors with accurate measurement of vessel position. The six principle types of DP reference systems are described in Chapter 6. © Marine Institute School of Maritime Studies 2014

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(4) Heading Reference Systems Gyro compasses provide the DP computers/processors with accurate measurement of vessel heading. Gyro compasses are described in Chapter 3.

(5) Environment Reference Systems Environmental reference systems are sensors which provide feedback data on wind speed and direction, also vessel attitude and motions. Wind sensors provide a value for wind direction and strength. Motion sensors provide values for roll, pitch and heave of the vessel. Sensors are described in Chapter 3.

(6) Power System A supply of power is required to operate the DP control elements, position reference, thrusters and other manoeuvering systems. A system is also required to manage and distribute the power to the various users. Details are found in Chapter 8.

(7) Propulsion Systems (Including Thrusters) Thrusters and other manoeuvering systems such as main propellers and rudders provide the propulsion force required to keep a DP vessel on the desired location and heading. More detail on the many possible variations is found in Chapter 7.

DP Operator The DP Operator (DPO) is the designated watchkeeping officer responsible for managing the Dynamic Positioning of the vessel.The DP operator (DPO) is an integral part of the DP system. Utilizing the DP console the DPO monitors the equipment, sets parameters, selects and deselects equipment and, most importantly, he/she is the last line of defence when problems occur.

Independent Joystick Independent joystick control is a control facility in a DP capable vessel fully independent of the DP system, allowing multiple thrusters to be controlled manually from a single joystick. The independent joystick functions the same as those found on the DP console. It is a backup control should the joystick (on the DP console) or the entire DP system fail. At times there may be a need to manoeuver the vessel under joystick control. The outside view, when using the joystick on the DP console, might not be ideal. Often the independent joystick is located with a better outside view. On many vessels the independent joystick is portable and can be moved around the bridge to a desired location. There are some DP equipped vessels that are not equipped with an independent joystick.

Other Sensors Other sensors (i.e. draft, tension, etc.) are fitted as required. Sensors are described in Chapter 3.

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Commercial DP Systems Dynamic Positioning Systems are manufactured by several different manufacturers. Current manufacturers include Bier Radio/Navis, General Electric (GE) , EMRI, Imtech, Kongsberg, L3 Communications, Marine Technologies LLC, Praxis, Rolls Royce and Symmetry. A DP operator may work on a vessel using a system from one of these manufacturers or they may work on a vessel using a system from another manufacturer (e.g., ABB, AutoNav, Kawasaki) that no longer produce DP systems but still has DP systems in service on board vessels. Irrespective of who manufactures the DP system, they all perform the same basic DP station keeping function. There may be some different modes of operation depending on the type of vessel and the manufacturer. The procedures for operating one DP system as compared to another may differ greatly. The layout and type of controls on the DP console will likely be quite different depending on the manufacturer. The method of accessing the different DP functions and the operation of the system may also be quite different. Manufacturers of DP systems, from time to time, come out with new or updated versions of their equipment. The operation of this new version may differ greatly from that of the old model, even though they are from the same manufacturer. Because all DP systems are not the same, the DP operator must ensure that they he/she has a full understanding of the DP system before operating it. The manual for the system should be consulted as well as any personnel familiar with the system who may be of assistance. The International Marine Contractors Association (IMCA) has published “The Training and Experience of Key DP Personnel” to provide guidance as to how much familiarization is necessary when an operator is confronted with a new DP system. DP system manuals for the systems from GE and Kongsberg, used during the course, are available for reading in the classroom. Each student will also be provided with copies of these manuals on CD.

Abbreviations Some abbreviations associated with DP include but are not limited to the following: AHTS ALP BOP CG COR CM CP DARPS DGNSS DGPS DP DPO DPS DQI DSV ESD FMCW FMEA

Anchor Handling Tug Supply Vessel Articulated Loading Platform Blowout Preventer Center of Gravity Center of Rotation Central Meridian Controllable Pitch Differential Absolute and Relative Positioning System Differential Global Navigation Satellite System Differential Global Positioning System Dynamic Positioning Dynamic Positioning Operator Dynamic Positioning System Differential Quality Indicator Divie Support Vessel Emergency Shutdown and Disconnection Frequency Modulated Continuous Wave Failure Modes Effect Analysis

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FP FPSO FSO FSU GNSS GPS HDOP HF HMI HPR IMCA IMO INS JSAH JSMH LBL LTW LUSBL MF MRU NMA OLS OLT OSV PID PME PMS PRS PSV RPM ROV SAL SBL SDP SPM SSBL STCW STL UHF UPS USBL UTC UTM VHF VRS VRU

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Fixed Pitch Floating Production Storage and Offloading Floating Storage and Offloading Floating Storage Unit Global Navigation Satellite System Global Positioning System Horizontal Dilution of Prescision High Frequency Human Machine Interface Hydroacoustic Position Reference International Marine Contractors Association International Maritime Organization Inertial Navigation System Joystick Auto Heading Joystick Manual Heading Long Baseline Light-Weight Taut Wire Long and Ultrashort Baseline Medium Frequency Motion Reference Unit Norwegian Maritime Authority Offshore Loading System Offshore Loading Terminal Offshore Supply Vessel Proportional Integral Derivative Position Measuring Equipment Position Measuring System/Power Management System Position Reference System Platform Supply Vessel Revolutions Per Minute Remotely Operated Vehicle Single Anchor Loading Short Baseline Simrad Dynamic Positioning Single Point Mooring Super Short Baseline Standards of Training Competence and Watchkeeping Submerged Turret Loading Ultra High Frequency Uninteruptable Power Supply Ultra Short Baseline Universal Time Coordinated Universal Transverse Mercator Very High Frequency Vertical Reference Sensor Vertical Reference Unit

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Notes

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Chapter 2 DYNAMIC POSITIONING PRINCIPLES

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Dynamic Positioning Principles A seagoing vessel is subject to environmental forces such as wind, waves, and current. The vessel has six freedoms of movement as shown in Figure 2.1. They are: Surge is vessel movement in the fore-and-aft direction (position movement). Surge is controlled by the DP system. Sway is vessel movement in the transverse direction (position movement). Sway is controlled by the DP system. Yaw is vessel rotation about the vertical axis. Yaw is change of heading and is controlled by the DP system. Heave is vertical bodily movement of the vessel. Heave may be monitored by but is not controlled by the DP system. Pitch is vessel movement, a rotation about an athwartships axis. Pitch is monitored but not controlled by the DP system. Roll is vessel angular rotation about a longitudinal axis. Roll is monitored but. not controlled by the DP system.

Heave

Sway (P&S)

Surge (F&A)

Roll Pitch Yaw (Heading)

2.1 - A Vessel´s Six Degrees of Freedom Figure 2.1 – A Vessel’s Six Degrees Figure of Freedom

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Dynamic positioning controls the vessel’s position relative to a point, either fixed or mobile, and also maintains its heading. This means that DP controls the motion of the vessel as far as surge, sway, and yaw are concerned (horizontal degrees of freedom). In Figure 2.2 we can see that environmental forces have caused a loss of vessel heading to starboard. Environmental forces have also moved vessel position forward and to starboard. The DP system determines the errors, determines thrust required to correct the errors and outputs commands to the thrusters to correct the errors. The vessel is turned to port to obtain the wanted heading and moved astern and to port to obtain the wanted position. The DP system is designed to keep the vessel within specified position and heading limits and to minimize fuel consumption and wear and tear of the propulsion plant. The operational limits are determined by the type of work the vessel is undertaking.

Figure 2.2 – Assessment of Errors

Center of Rotation The DP system works to maintain a designated point on the vessel, known as the Center of Rotation (COR), on position. The Center of Rotation is a reference point within the vessel about which the vessel will rotates when in full automatic positioning mode. Any requested heading changes occur by having the vessel rotate about the COR. Normally the default COR is located at the Center of Gravity (CG) of the vessel or, on some vessels, a point half way between bow and stern. A vessel DP system may be configured with more than one Center of Rotation, operator-selectable. Alternatively, on some DP systems, the operator may enter the location of a desired center of rotation manually, if those already programmed into the system don’t meet requirements. Vessel positional deviations or errors are given in terms of distance of the COR from the Set Point, or desired, position. An example where an alternative COR might be used would be a vessel using an A Frame, at its stern, to lower and place a manifold on the seabed. During the operation there is a change in current direction which dictates a change in vessel heading. The manifold has just touched down on the seabed but cannot yet be disconnected from the lifting wire on the A Frame. Heading change would normally take place about default COR at CG. Rotating about CG would cause the wire 2-4

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on the A Frame and attached manifold to swing through an arc, potentially causing damage. This could be avoided by switching rotation point to the A Frame and having the vessel rotate about the wire and manifold.

Closed Loop Control System In the first DP systems PID controllers were used and may still be used today in simpler DP systems. Modern controllers use a mathematical model of the vessel. Model based systems are described later in this chapter. An automatic controlled closed loop system is actuated by a signal dependent upon deviation (error) between the input (required) and feedback (actual) values provided by a sensor. This sensor may be a gyro for heading error or a position reference system for position error. The DP system calculates the deviation between the actual and the required position or heading. The Proportional/ Integral/Derivative (PID) controller determines the required force to correct the error. With Proportional control the required force is determined by how far the vessel is offset from commanded heading/position. As the vessel gets further away from the commanded value, the thruster commands become greater. With Integral control the required force is determined by calculating forces acting on the vessel over a period of time. This allows the system to counteract steady forces which are acting on the vessel. Further details on these forces are found later in this section. With Derivative control the required force is determined from vessel motion and it acts to reduce vessel motion to zero. The faster the vessel is moving, the larger thruster commands will be in the opposite direction to slow the rate of turn/speed. The determined forces are sent to the actuators (thruster controls) to command the required thrust levels.

Figure 2.3 â&#x20AC;&#x201C; Closed Loop Feedback Control System

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The Mathematical Model Modern DP systems use a mathematical model of the vessel which is a software algorithm containing all vessel positioning characteristics. It is a mathematical description of the vessel and how it reacts or moves due to the environmental forces acting upon it. This mathematical model is affected by the same forces as the vessel itself. Wind force is calculated as a function of the measurement of wind (speed and direction). Thruster forces are calculated as a function of the propeller/pitch/RPM and direction. The computer is programmed to estimate the forces caused by sea current and waves. It estimates the vessel heading, position, and speed in each of three degrees of freedom - surge, sway, and yaw. The model itself is never a 100% accurate representation of the real vessel. The output from the mathematical model is filtered using “Kalman Filtering” techniques and the model is continuously corrected. A Kalman Filter” is an algorithm which, in a DP system, is utilized to generate an optimum estimate of position from incoming data signals, filtering noisy and intermittent data, and applying weighting values to individual signal data streams. The vessel’s heading and position are measured using the gyro(s) and position reference(s). This data is compared to the predicted or estimated data produced by the mathematical model and the differences are calculated. These differences are then used to update the mathematical model to the actual situation.

Dead Reckoning Mode The mathematical model/Kalman filters provide the system with optimum noise filtering of heading and position measurements, a very good combination of data from different reference systems, and, in the absence of position and/ or heading measurements, the system continues to function in a “Dead Reckoning” mode or “DR mode” for a period of time based on the information stored in the memory. This mode can also be known as “Model Control”. The system will default to this mode if position or heading reference is lost. Over time, positioning/heading accuracy will downgrade, due to the fact that the mathematical model is not being updated as to all changes in environmental conditions (heading and or position measurements having ceased to be input to the system). The time it takes for the model to degrade to the point where positioning accuracy becomes unacceptable will depend on how quickly environmental conditions change after model control is initiated and how accurate the model was when entering model control. Model control may cease to work effectively after only a few minutes.

Wind Feed Forward In order to respond to wind forces as quickly as possible, a concept known as “feed forward” is used. This means that the controller doesn’t wait for the vessel’s reaction to wind forces to be measured as a deviation from the wanted heading and/ or position, but applies thrust to counteract the wind induces forces as soon as they are detected by the wind sensors. The use of wind sensors is necessary for wind feed forward. See more information in the wind sensors section of Chapter 3.

DP Current Even when the wind force is counteracted, the vessel may still be moving out of position. This movement is due to forces that are not measured directly such as swell, tidal currents, waves, sea currents, etc. The system builds up a history of these forces over a period of time and then calculates and applies the thruster demand to counteract them. This model of forces is continuously updated to allow for changes in environmental forces.

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DP Current is a term loosely and erroneously used to describe the sea current derived from the mathematical model. It actually consists of a vector which represents sea current and all other unknown forces. An unknown / external force is any force, measured or unknown, which affects the positioning or heading control of the vessel. Typical examples of external forces include those caused by wind, waves, current, hawser tension, cable tension, etc. If no wind sensors are selected, and, for that reason, there is no wind feed forward, the effects of the wind on the vessel’s surface will be calculated within the current and wave effects. With no wind sensors enabled, the wind becomes an unknown force and is calculated as a component of the DP Current In reality, sea current is the horizontal movement of water (set, or direction, and rate) experienced by the vessel. Since this value cannot normally be measured directly from the vessel, the value displayed by the DP system is a calculated value from mathematical modelling. The displayed value of “Sea Current” may contain errors and cannot be relied upon to show the actual sea current. Some DP system manufacturers use the term “Sea Force” to describe the residual vector referred to as “Sea Current”.

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MEASURED WIND SPEED & DIR.

MEASURED POSITION & HEADING

Position & Heading Difference

KALMAN FILTER

WIND MODEL Wind Force

ERROR COMPUTATION

Estimated Position & Heading

Error Compensation Force

Vessel Model Update

Thruster Force

External Forces

Draught Input

VESSEL MODEL Estimated Position & Heading

Estimated Speed

Drag Force

Wanted Position & Heading

DRAG COMPUTATION

Position & Heading Deviation DAMPING CONTROL

JOYSTICK GAIN CONTROLLER

Force Demand for Axes under Manual Control

Joystick Gain & Linearity

Gain Settings

Force Demand for Axes under Automatic

Resulting Force Demand THRUSTER ALLOCATION

Feed Forward

Thruster Allocation Mode & Thruster Enable

Thruster Setpoints POWER OVERLOAD CONTROL

THRUSTER MODEL

Generator Status Bus Switch Status Power Consumption

Thruster Commands

Thruster Feedback

THRUSTER FEEDBACK SYSTEM

GAIN CONTROL

THRUSTERS

THRUSTER COMMAND SYSTEM

Figure 2.4 – DP System Block Diagram 2-8

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DP System Operation Reference is made to Figure 2.4 throughout this section which describes an example of the operation of a modern DP system that uses a mathematical model. Vessel speed and direction of motion can be calculated when the forces acting on the vessel and the vessels mass are known. Forces acting on the vessel include: wind, sea current, tidal current, wave drift forces, thruster forces and, when the vessel is moving, drag forces. The Vessel Model can be seen as a simulator simulating the vessel motions. Based on input information it calculates the vessel speed and direction of movement in real-time. Inputs to the vessel model are environmental forces, thruster forces, drag forces, mass and position and heading. Output is estimated position and heading, predicted position and heading and estimated speed. The only environmental force measured for a normal DP system is the wind. The Wind Model consists of three tables of coefficients, one for surge, one for sway and one for yaw directions, covering the vessel 360º. When the direction of the wind is known the coefficients for that direction are determined and the force acting on the vessel is calculated. There will normally be only one set of wind coefficients, but on vessels changing draught drastically during the operation there can be sets for different draughts. Other forces acting on the vessel can be directly input into the vessel model from a variety of different sensors (i.e. Hawser tension, pipe tension, plow tension, etc.) Examples of the different force measurement sensor inputs to the DP system are found in chapter 3 of this manual. Vessel mass is derived from the Draught Input. This can be entered manually or be provided by direct input from a draught sensor or sensors. Some DP systems have draught as a fixed value in the software, which means that the vessel has to keep the correct draught during the DP-operations. If not the vessel will oscillate if it is floating higher in the water (lower mass), or react slowly if it is floating lower in the water (higher mass). Since only wind force is being measured, the other forces acting upon the vessel have to be calculated. This is done by means of a slowly varying low pass filter, which is controlled by the difference between the predicted position and heading and the measured position and heading from the position references and gyros. The result of the calculation is a combined, “unknown” force which takes into account all unmeasured forces acting on the vessel. The output from the filter, the Error Compensation Force, is added to the wind force as an external force and will effect the speed calculations and thus the predicted position output from the vessel model. The output from the filter will change until the Predicted and Actual Positions and Headings agree. The DP system has now adjusted itself so that the total input to the vessel estimator is equal to the actual forces acting upon the vessel. The error compensation force not only contains sea current and wave drift forces, but also other forces acting on the vessel together with all errors in wind measurement, wind model and calculated thruster forces. The updating of the error compensation force is only possible when we receive acceptable position and heading measurements. This force is displayed on the DP console and represented to the DPO as current, often referred to as “DP Current” from a direction which is the resultant of all unknown forces acting on the vessel (Figure 2.5).

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Figure 2.5 â&#x20AC;&#x201C; Error Compensation Force

Settling time is required at the beginning of DP operations and is the amount of time necessary for a DP system to obtain optimum position and heading keeping performance. This amount of time is related to the speed at which the mathematical model builds. Positioning accuracy will be downgraded at the beginning of DP operations due to the fact that the system does not know the magnitude or direction of all forces acting on the vessel. The low pass filter has a filter constant of 30 minutes. This means that the DP system needs 30 minutes in Manual or Auto mode with good position and heading measurements before it has calculated the error compensation force. However, after 10 to 15 minutes it is quite accurate (Figure 2.6). Vessel position/heading deviations should normally reduce over 30 minutes as the calculation of the error compensation force becomes more accurate. Actual deviations after the force is calculated will depend on the environmental conditions, the degree to which environmental conditions are changing and on vessel capability. The vessel model is, as mentioned earlier, calculating the vessel speed and direction of movement. The water will resist this movement, e.g. setting up a force in the opposite direction of the motion. Using Estimated Speed the DP system will perform a Drag Computation which results in a Drag Forces which update the vessel model. The drag force is important factor in the calculation of an accurate vessel speed.

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Figure 2.6 â&#x20AC;&#x201C; Error Compensation Force Calculation Time

ÂŠ Marine Institute School of Maritime Studies 2014

The Vessel Model outputs Estimated Position and Heading. The DPO inputs Wanted Position and Heading. The two are combined to give Position and Heading Deviation. The deviations generate a thrust demands relative to the size of the deviations and the Gain Settings selected by the DPO. Gain is a factor within the DP system which determines the magnitude of power applied in response to position or heading deviation. Gain is normally an operator-selectable function. Low Gain allows positioning using less power and thrust, economizing in fuel consumption, while a High gain setting will use greater power and thrust values which may result in more accurate positioning. The gain to be set will vary depending on vessel capability and on environmental conditions. A typical configuration would allow the DPO to select Low, Medium or High system gain. As an hypothetical example for position deviations on a particular vessel, 2 tonnes of thrust might be demanded per metre of deviation on Low Gain, 3 tonnes for Medium Gain and 4.5 tonnes for High Gain. Some systems allow the setting of gain individually for the Surge, Sway and Yaw axes, with gain settings input from 0-100% for each of the axes. The Resulting Force Demand that is needed to keep the vessel at the required heading/position or to return it to the required position/heading is composed of the following: »» »» »» »»

Force Demand for Axes Under Automatic Control Force Demand for Axes Under Manual Control Feed Forward Damping Control

The vessel may have all three axes under automatic control, all three axes under manual control or a combination of the two. When any of the axes are not under automatic, the joystick is used to manually control the force exerted by the vessel’s propulsion system on those axes. Forces input by the joystick will be subject to joystick settings, depending on the DP system being used. In order to counteract changes in external forces as soon as they are detected, rather than first allowing the vessel to drift away from required position/heading, the measured and calculated external forces acting on the vessel are Fed Forward as an additional force demand. The resultant force demand in the surge and sway axes (the directional force demand), and the yaw axis (the rotational moment demand), is applied to the Thruster Allocation. Thrust allocation /Thruster Allocation is a term used to describe the algorithm which determines individual thruster and propeller outputs from an overall positioning and heading vector demand.This contains information relating to which thrusters/propellers/rudders are available for DP control, their locations on the vessel, allocation mode selected (i.e. Fixed azimuth, variable azimuth, etc.) and what their pitch/r.p.m./ thrust characteristics are. Setpoints are the desired values of any controlled variable, i.e. Set Point heading, and Set Point position.´Thruster Setpoints are generated as pitch and/or rpm signals for each thruster/propeller under DP control. Rudder angle signals are also generated when rudders are under DP control. The demand is distributed in such a way as to obtain the directional force and rotational moment required for position and heading control, while also ensuring optimum thruster/propeller use with minimum power consumption and minimum wear and tear on the propulsion equipment. If a thruster/propeller is out of service or deselected, the “lost” thrust is automatically redistributed to the remaining thrusters/propellers. Should the system detect that the available thrusters/propellers/rudders are unable to provide the required force demand an “Insufficient Thrust” alarm is generated to alert the DPO to the situation.

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DP systems normally work with “Heading Priority”. This is a facility within the positioning algorithm of a vessel DP system allowing heading deviation to be given greater weighting than vessel position. Thus, if position and heading excursions occur simultaneously, the system will prioritize the reduction of heading deviation.If it is not possible to maintain both the rotational moment and the directional force demand due to insufficient available thrust, priority is normally set to obtain the rotational moment demand (heading). If for example a change of heading is input with too fast a rate of turn, the DP system, due to priority on the heading, may sacrifice position to provide sufficient power to obtain the rate of turn requested by the DPO. On some DP systems there is a “Heading Priority”/ “Position Priority” option available which can be selected by the DPO if required. Thruster Setpoints are applied to a Power Overload Control function. This function is supplied with information regarding generator status, bus switch status and power consumption levels. If thruster setpoints are predicted to overload the switchboard (which may cause a vessel blackout), power is reduced on the connected thrusters/propellers by reducing the pitch/rpm demand. The reduction is shared between the connected thrusters/propellers in such a way that the effect on the position and heading is minimized. A “Demand Reduced by Power Management/Power Chop” alarm alerts the DPO to the problem. This function is internal to the DP system and acts as an addition to the vessel’s own Power Management System (See Chapter 8). The power reduction limits are set at lower overload levels than the load reduction initiated by the Power Management System. Thruster Commands passed to the Thruster Command System and then to the thrusters/propellers themselves. Feedback is any data measured by a sensor which is monitored by the DP system and acted upon within its computations. Thruster Feedback signals are passed to the Thruster Model. A comparison is made between command and feedback signals. Any difference will indicate that a thruster is not reacting as required. A “Thruster Error” message alerts the DPO to any problems. Due to the fact that the thrusters exert a force on the vessel, the Thruster Model updates the Vessel Model with the Thruster Force applied by the vessel’s propulsion system.

DP Capability Plot Any DP system operating with all the elements working properly can perform satisfactorily if the environmental forces do not exceed the operational capability of the vessel. If the environmental forces exceed thruster output, the vessel will not be able to keep station. The operator(s) should fully understand the vessel’s capabilities, limitations, and the need to monitor the environmental forces at all times. This is especially important when the vessel is close to its capability limits. Before commencing DP operations, an assessment must be done of the capability of the vessel under the expected conditions. The capability of the vessel to maintain station depends on available power, thruster configuration, size and shape of the vessel, expected environmental conditions, and the type of job to be performed. A DP operational capability graph should be available for inspection in order to get a detailed assessment of the vessel’s capabilities. A capability plot/capability diagram is an approximate indication of the positional and heading capability of the vessel under a variety of stated conditions. A more realistic indication is given by the online capability plot, in which the data is recalculated at intervals, taking into account the conditions obtaining at the time of calculation.The diagram is a polar graph showing the weather heading against wind speed. The wind is in knots and the wind direction is in relation to the ship’s head (relative bearing). A number of curves are plotted. There is one representing the ship’s maximum capability with all thrusters operational. A curve may be plotted representing the ship’s operational capability with worst case failure. This would be a system failure resulting in the greatest functional degradation within the DP system but not a total system failure. An example would be 2-12

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Taut Wire: »» Review subsea worksite layout so as not to position clump weight in areas where it might cause damage to subsea equipment. »» Ensure adequate wire length on the winch for the water depth at the worksite. »» Water depth may be such that the weight of the wire causes it to bend, creating angle measurement errors. »» Current may be too strong (i.e. bending of the wire) to use the taut wire at the worksite. »» Water depth may be too shallow to use the taut wire. Example: Small vessel movements (1 - 3m) while on DP will cause wire to move outside maximum allowed angle limits or touch the vessels hull if taut wire is used at worksite. »» Determine maximum vessel movements that will be possible before having to replumb taut wire. »» Consider vessel movement in forecast sea conditions with regard to launch and recovery of clump weight as well as taut wire ability to operate properly in forecast conditions (i.e. ability of the winch to respond quickly enough to vessel motion). »» Determine the type of bottom at the worksite. A rocky bottom might mean that the clump weight may drag as smaller than normal angles. A soft muddy bottom might mean that the clump weight will sink into the bottom and be difficult to recover if left in location for long periods without being replumb. »» Consider any interference that deployed clump weight may cause for subsea operations such as diving or ROV. »» Determine if the wire has been cropped since last use and the counter properly reset. RadaScan/RADius (Microwave Systems): »» Determine a suitable location for the responder/responders or transponder/transponders on the platform. »» Obtain permission to locate the responder/responders or transponder/transponders at the chosen location. Having more than 1 responder or transponder will provide backup in the event that one becomes unusable. »» If responders or transponders are already set up at the worksite, they may be used instead. If permission for the use of these transponders is granted, obtain the identification codes. »» Determine how responder/transponder is to be transferred to deployment location and determine who will set it up. »» Review work location to determine if the scanner/interrogator on the vessel will have line of sight with the responder/responders or transponder/transponders at all times during the operation. Consider objects that might block signals such as platforms, other vessels, crane operations, etc. It might be determined that more than one reflector has to be installed to ensure that there is at least one available at all times. »» Ensure that responder/transponder is located to avoid possible interference caused by platform operations or personnel. »» Consider scanner/interrogator and responder/transponder heights and positions with regard to limitations of vertical and horizontal signal beam widths. »» Check remaining battery life if responders/transponders are battery powered. »» If responders/transponders require platform power, determine availability of suitable power supply. »» There may be a requirement for the responders/transponders to be intrinsically safe when used in some areas. As far as possible, operational status of reference systems should be checked before the job commences. As mentioned above, there will be a minimum number of references required for each job. If a vessel is equipped with references in addition to that minimum requirement, it may be prudent to use these addition references or at the very least have them on standby and ready to go. This will provide backup in case of a reference system failure and possibly prevent suspending DP operations because insufficient references are available. 10-10

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Operational Considerations From Chapter 4 we can see that a wide variety of operations are conducted by DP vessels. The operation being conducted requires consideration when planning operations. Aspects of the operation may require consideration with respect to the DP system. Example: A vessel is to conduct DP operations where air divers are to be deployed. When conducting such operations there are safety requirements regarding how close the divers can get to oper ational thrusters. Figure 10.2 shows a diagram which shows maximum allowable umbilical lengths when divers are working at various depths. Consulting this document during operational planning might indicate that the proposed vessel position would have the divers working at an unsafe distance from the thrusters. Vessel position or heading may have to be adjusted to provide a safe distance. It may be determined that a particular thruster could not be used during the operation. This might impact on vessel capability or required redundancy.

MSV CHALLENGER SAT AND AIR DIVE SAFE UMBILICAL LENGTHS

Bell Dive (Moonpool)

18m

Thruster 5m No Go Areas 20m

Depths Below Sea Level

10m Diver Depth

20m Diver Depth

Air Dive

27m

Thruster 5m No Go Areas 29m

25m

30m Diver Depth

34m

32m

40m Diver Depth

41m

Maximum Umbilical Lengths

40m

50m Diver Depth

48m

56m

49m 60m Diver Depth

Figure 10.2

10.2

ÂŠ Marine Institute School of Maritime Studies 2014

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Contingency Planning Failures or emergency situations can occur at any time during a DP operation. The planning process should include contingency planning to cover procedures to be followed if the operation does not go as expected. An essential component of any DP operation is an escape route. It is an identified and defined route away from any hazards or nearby structures. It can also be known as an emergency exit strategy which is a pre-planned route away from hazards within any working area or worksite. There should always be a planned escape route that positions the vessel at a safe location in the event of a DP system failure. This should include the approach to the worksite, conducting the DP operation and the departure from the worksite. By having an escape route planned in advance, there is no delay while the DPO decides where to move the vessel and the safest route to get there. An escape route that is planned in advance can be thoroughly reviewed for problems. A plan that is formulated in haste after the DP failure occurs may cause more problems than it solves. Example: A vessel is conducting DP operations close to a platform and is in a blow on situation. The deployed ROV has connected a load to the crane wire and the load has just been lifted off the bottom when a partial blackout occurs. Half of the vessels power supply is lost along with half of the thrusters. Redundancy had been confirmed before commencing the operation and sufficient power and thrusters remain online to hold the vessel on station. Power has however failed to the crane and the load is suspended and cannot be raised or lowered. Due to the fact that the vessel now has no redundancy and is in a blow on situation, a decision is made to move the vessel to a location where it will drift clear if remaining power fails. The fastest way to move the vessel to safety (the escape route) is to move astern. While making the move the suspended weight on the crane hooks something on the seabed causing loss of heading and near contact with the platform. Before the vessel can be stopped the crane wire parts and the load falls to the seabed where it causes damage to a pipeline. A subsequent investigation determines that a new pipeline had recently been laid from the platform. A hold back line used to commence the lay was run from the platform leg to the pipe and had not been removed. This information was included in documentation sent to the vessel prior to commencement of the job. The supplied information was not adequately reviewed during planning for the operation and in this case, the escape route was decided in haste after the problem occurred, without considering all available information, resulting in vessel and field equipment damage.

At the point that the planned escape route is utilized, the vessel may be experiencing reduced power or thrust capability. The prospect of such reduced capability should be taken into account as the vessel might not be capable of utilizing the planned escape route. Contingency plans should be altered as required to take into account changes in conditions that occur while the DP operation is being conducted. For example, weather conditions may change or a vessel may arrive on location and be positioned so as to block the planned escape route. Contingency planning should also take the form of deciding what action to take should a problem occur. The DPO at the control desk should, as far as possible, preplan for things that may go wrong. â&#x20AC;&#x153;Given the job at hand, what action will I take if this particular fault or problem occurs?â&#x20AC;? would be the sort of planning the DPO should undertake. Knowing what you are going to do when a fault occurs saves valuable time and may prevent incorrect decisions. Example: A thruster fails to full pitch. The DPO reviews available information and determines that the thruster has failed to full pitch. Having previously reviewed procedures for such a problem, the DPO quickly shuts down the correct thruster minimizing heading/position excursions. The same problem occurs but this time the DPO has not preplanned. After determining the fault the DPO must now decide what action to take. On making the decision to shut down the thruster the DPO rushes to the thruster control panel and pushes the emergency stop. All the buttons are close together on one panel and not having reviewed the procedure, the DPO accidentally stops the wrong thruster. The time taken to decide a course of action may have been short, but it does allow for a greater heading/position excursions. Stopping the wrong thruster, while leaving the faulty one running, will certainly compound the problem. 10-12

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While on DP it is a good practice to note thrust and power settings applied by the DP control system on an ongoing basis. If a failure occurs which requires the DPO to resort to manual control to hold the vessel on location, using either joystick or individual thruster controls, the settings that were previously being used are known. Thus, the DPO has a starting point regarding the amount of thrust to apply manually. Orientation of the joystick is also important as a joystick or thruster control accidentally pushed the wrong way can move the vessel towards an obstruction as opposed to being held in position away from that obstruction. It must be noted, that the reaction to a particular problem will depend on the circumstances of the case and may not always be the same. The DPO can never plan for all eventualities but can plan for faults that occur with DP systems in general and faults that could occur/have occurred on his/her particular vessel.

Checklists A checklist is a pre-prepared list of tasks and checks to be completed prior to commencing an operation or an individual phase of an operation. Checklists ensure that the DP system is working properly and it also ensures that there is a standard set of checks carried out by all DP operators on board the vessel. Checklists should be completed at various stages of the DP operation. The type, frequency and content of the checklists will vary depending on the vessel and the type of operation. The “name” of the checklist can vary from company to company but the content and purpose of a checklist may be the same. A “Pre-DP” checklist is a checklist intended to be completed immediately prior to transferring the vessel from conventional navigation to DP control. There may be separate Pre-DP checklists for bridge, and Machinery Control Room. A “Pre-operational” checklist is a checklist intended to be completed once the vessel is established under DP control, before commencing her operational tasks. The following are some checklist types that might be performed: »» When arriving at a new location and setting up on DP a comprehensive “Field Arrival”, “New Location” or “Pre- DP” checklist is completed. This may be completed even if the new location is close to the old location. »» Before starting operations under DP control a “Pre-operational” checklist is completed. Vessels involved in different operations may have requirements for checklists at certain times during the operation. On a dive support vessel there would be a requirement to complete a “Pre–operational” (perhaps called Pre-Dive”) DP checklist before the diving bell or air divers are permitted to enter the water. »» When DPOs change watch a “Change of Watch” DP checklist is completed. »» At intervals (i.e. every 4 or 6 hours) during the watch a “Watchkeeping” DP checklist is completed. The following is an example of what a “Pre-Operational” checklist for a dive support vessel might contain.

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MSV Challenger Pre-Operational Checklist Note: Add comments where required. Date ____________________

Time ____________________

Position

Location ____________________

N ____________________

E ____________________

Water Depth ____________________ Lights / Shapes (On/Up)

Y/N

Read Latest Forecast

Y/N

Lamp/Alarm Test Completed & O.K.

Y/N

System Setup Computer Online

Operator Station in Use

Centre of Rotation Selected

____________________

Speed Setting ____________________ Turn Rate Setting ____________________ Acceleration/Retardation Settings: Low Speed Acceleration Factor

Surge _____ %

Sway _____ %

Yaw _____ %

Retardation Factor

Surge _____ %

Sway _____ %

Yaw _____ %

High Speed Acceleration Factor

Yaw _____ %

Retardation Factor

Yaw _____ %

Gain (Select 1 of the 4 Below) ___ High Precision

Gain Setting:

Low

Gain Setting:

Surge _____

___ Customized High Precision ___ Relaxed

Outer Radius ____________

___ Green DP

Outer Radius ____________

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Medium

High

Sway ______

Yaw ______

Inner Radius ____________

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Joystick Thrust

Reduced _____

Joystick Precision

High Speed _____

Joystick Environmental Comp.

Surge _____

Full _____ General _____

Sway _____

Low Speed _____

Yaw _____

DP Mode

Standby _____

Joystick _____

Auto Position _____

Auto Yaw _____

*Auto Pilot _____ *Auto Track _____

*Follow Target _____ *Trackline _____

Auto Surge _____

Auto Sway _____

* Before using, review specific settings for these modes and complete checklists as required. Alarms Alarms Page Checked

Y/N

Position Alarm Settings

Warning _____

Alarm _____

Enabled Y / N

Heading Alarm Setting

Warning _____

Alarm _____

Enabled Y / N

Warning _____

Alarm _____

Enabled Y / N

Cross-Track Alarm Settings

Propulsion Joystick Operational

Y/N

Thrusters Available for DP Control

#1 __ #2 __ #3 __ #4 __ #5 __ #6 __ #7 __

Thrusters Selected

#1 __ #2 __ #3 __ #4 __ #5 __ #6 __ #7 __

Thruster #3 on

Bus 1 __ Bus 2 __

Thruster Setpoint/Feedback O.K.

Rudders Available for DP Control

Port __ Stbd. __

Rudders Selected

Rudder Setpoint/Feedback O.K.

Y/N

Thruster Mode Selected _____________________________________

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Power Status Generators Available

#1 __ #2 __ #3 __ #4 __ #5 __ #6 __

Generators Online

#1 __ #2 __ #3 __ #4 __ #5 __ #6 __

Main Switchboard Split

Y/N

Power (if Bus is Common)

Used ____________

Power (if Bus is Split)

Available ____________

Bus 1: Used ____________

Available ____________

Bus 2: Used ____________

Available ____________

UPS Checked & O.K.

Y/N

Sensors Gyros Available Gyro in Use

#1 __ #2 __ #3 __

Differences Checked & Acceptable Vessel Heading in Use Wind Sensors Available

Wind Sensor in Use

Differences Checked & Acceptable Wind Speed & Direction in Use VRS Available VRS in Use

____________ ° #1 __ #2 __ #3 __ #1 __ #2 __ #3 __ Y / N _____________________________________

#1 __ #2 __ #3 __

Differences Checked & Acceptable Values Used

Y/N

Y/N Heave _____

Draught Sensor Available

Y/N

Draught Input

Sensor __

Draught Input Checked & Acceptable

Y/N

Pitch _____

Manua __

Roll _____

Operational __

Transit __

Draught in Use _____________________________________

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Reference Systems

Available Selected

Artemis

Y/N

DGPS 1

Y/N

DGPS 2

Y/N

Fanbeam

Y/N

Y / N Targets ____________

HPR 1

Y/N

Y / N Transponders _____ _____ _____ _____

HPR 2

Y/N

Y / N Transponders _____ _____ _____ _____

Radius

Y/N

Y / N Transponders _____ _____ _____ _____

Taut Wire Port

Y/N

Taut Wire Stbd.

Y/N

Gate Valves

Port: Open / Closed

HPR Poles

Port: Down / Up

ROV Transponder

_____

Bell Transponder

_____

Datum Settings Checked & O.K.

____________

Stbd.: Open / Closed Stbd.: Down / Up

Diver Transponder _____

Y/N

Communications Tested & O.K. (as applicable) Crane Cab/Cabs

Y/N

Engineroom Checklist Complete

Y/N

Dive Checklist Complete

Y/N

ROV Checklist Complete

Y/N

Dive Control Engine Control Room ROV Control

DP Status Lights Y / N

Checklists

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Vessel Capability Trends Page Checked

Y/N

Capability Plot Setup & Checked

Y/N

Consequence Analysis Enabled

Y/N

Deselect Thrusters

Position Maintained

Deselect Thrusters

Position Maintained

#1, (#3), #5 & #7 (Only if thruster #3 is connected to BUS 1) Y/N

Reselect Thrusters

#2, (#3), #4 & #6 (Only if thruster #3 is connected to BUS 2)

Y/N

Vessel on Auto DP for 30 Minutes

Y/N

DP Current

_____________________________________

All Page Settings Checked Printer Online

Reselect Thrusters

Y/N Y / N Print Status

Y / N

Signed _________________________________

Date _________________________

Signed _________________________________

Date _________________________

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ÂŠ Marine Institute School of Maritime Studies 2014

Initial DP Setup On arrival at the work location, the vessel will have to switch from transit to DP mode. The main propellers and rudders or the azimuth thrusters used for propulsion during transit may also be used for DP. The engine room will be informed of the intention to commence DP operations and any extra thrusters required for DP will have to be started as per vessel procedures. The thrusters should be tested manually to ensure proper operation. Any required load or reload of DP computers should be completed before entering DP mode. The position reference system or systems to be used for the operation (taking into account factors discussed previously) should be checked for readiness. Sensors (gyro, wind, motion and others as required) would also be checked for readiness. Any gyro and magnetic compass errors present to be determined. The mathematical model requires time to build up, when first entering DP mode. Vessel position is likely to oscillate for a period of time during this process. When entering DP mode, there is no guarantee that all components of the DP system are going to work properly. For these reasons the vessel should be set up on DP at a location well away from anything that the vessel might collide with because of position oscillations or DP system failures. If the worksite is in open water with no obstructions in the area then the setup location can be at or near the worksite. If there are obstructions near the worksite (i.e. work location 15m from the side of a platform) the setup should be completed at a distance well clear of the obstruction. Depending on vessel and field procedures this may mean setting up outside the platform 500m exclusion zone. This a defined area around an offshore structure or complex within which vessel and other operations are within the jurisdiction of the Offshore Installation Manager (OIM). Commonly this exclusion zone is set at 500m but may vary. When ready to enter DP mode the vessel is normally stopped and control of the thrusters is switched from manual to DP control and the thrusters are selected on the DP desk. Reference systems, sensors and thrusters are enabled at the DP desk as per system operating procedures. The DP joystick can now be tested as part of the appropriate DP checklist required when the vessel starts operations at a new location (see items to be reviewed on sample checklist above). It is important to remember that the vessel speed should ideally be as close to zero as possible when entering Auto DP mode. The same would apply for rate of turn. The possibility exists to place surge, sway and yaw under DP control all at once. If this is done and the vessel is moving the DP system will attempt to stop the vessel at the current position and heading. This can result in large amounts of thrust being used and can, in some circumstances, result in partial or full vessel blackout depending on power consumed. A smoother transition can usually be accomplished by entering DP one step at a time. The vessel can be steadied on heading using the joystick and the auto yaw selected. Next the speed in the surge axis can be reduced to as close to zero as possible and auto surge selected. Finally the same is accomplished with the sway axis and when auto sway is selected full DP control is enabled. On some DP systems surge and sway are switched into DP together and cannot be manipulated independently. Some DP systems have functionality that prevents entering Auto DP mode when speed or turn rate is excessive. When commanded to enter Auto DP mode, these systems will first slow the vessel to an appropriate speed and only then will the mode be activated. After the vessel is on full Auto DP, time is taken for the vessel to settle down on position. The mathematical model will build giving an indication of the DP current in the area. As the current strength and direction becomes apparent, changes may have to be made in the operational plan to reflect the newly obtained information. When making any changes it should be noted that although the worksite is nearby, there is a possibility that environmental conditions may not be the same at that location. The DP current in open water might be different than at the platform due to environmental interaction with the platform structure or subsea features. Previously mentioned procedures can be utilized to determine vessel capability and redundancy. Vessel redundancy can be observed by putting the vessel on the desired working heading and then simulating the worst case failure by deselecting the appropriate thrusters. The observed vessel performance may dictate that the heading previously chosen for the worksite will put the vessel beyond its limits with regard to the required level of redundancy. A new heading and/or position for the worksite may have to be chosen or the DP operation at hand may have to be postponed to await more favorable conditions. ÂŠ Marine Institute School of Maritime Studies 2014

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Communications Good communications between DP and all parties involved in the DP operation are essential at all times. The means of communication should, as a minimum, be duplicated to provide backup in the event of system failure. Communications systems used can consist of telephones, sound powered telephones, talk back systems, UHF radios, VHF radios and DP status lights (see below). With reliable communications all parties involved in the operation can inform each other about existing or planned changes in operational status. Modes of communication should be checked for correct operation, before commencing DP operations (often an item on DP checklists). Some examples of two way lines of communication to be established are as follows: »» »» »» »» »» »» »» »» »» »» »» »» »» »»

DP and dive control (dive support) DP and ROV control (any vessel using ROV) DP and engine control (all vessels) DP and installation (all vessels in close proximity or within 500 zone of platform) DP and drill floor (drilling vessels) DP and production control (floating production) DP and gangway control position (floating accommodation platforms) DP and crane cab(s) (any vessel conducting lifting operations) DP and ballast control ( heavy lift vessels) DP and lift control personnel (heavy lift vessels) DP and cargo/platform loading control (shuttle tankers) DP and cable/pipe lay personnel (cable/ pipe lay vessels) DP and tension control (cable/pipe lay vessels) DP and trencher/plow control (cable/pipe lay vessels)

DP Alert Levels On a DP vessel, there may be a system of alert levels to indicate the status of the DP system. An example of alert levels might be as follows:

Green

Yellow -

degraded operational status; with the equipment on line, safe working limits are being exceeded but a loss of position is not taking place and should not take place unless there is another fault, failure or mistake.

Red

emergency status; there is a loss of position, or position loss is inevitable.

n ormal operational status, adequate equipment is on line to meet the required performance within the declared safe working limits.

Some vessels have an additional Blue or White advisory level between Green and Yellow. Alarms indicating status are visual (lights) and depending on status level (Red) audible. The exact meaning of each alert level and the procedures to be followed in the event of a particular level will vary depending on the type of operation being conducted.

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Worksite Approach After the vessel position has settled the approach to the worksite can begin. We will assume for this example that the worksite is located 15m from the side of a platform and that up to this point the vessel is within required capability limits. Having obtained permission to enter the 500m zone, the vessel has been set up on DP at a distance of 300m from the platform (see Figure 10.3). Vessel heading has been set to that required at the final work location. The approach is to be made on Auto DP from this distance. The vessel will approach using a series of short position moves as opposed to making one move which places the vessel directly at the worksite. A few minutes settling time between moves will allow the mathematical model to update for the new location. Initially a series of 50m moves are used. When getting close to final position (about 50m) the moves are reduced to 10m at a time with the final few moves at 5m each. During the final moves, close to the platform, vessel speed should be kept slow at 0.2-0.3 knots. The low speed will minimize overshoots when arriving at a new position, reduce thrust used to stop the vessel at the position and make it easier to stop the vessel should problems occur. As the vessel moves towards the platform, fore/aft position is adjusted to align the vessel with desired work location.

Entering 500m Zone

Transfer Control to DP Desk Joystick Control Auto DP

Moving Towards Worksite

Moving Astern to Align with Worksite

Reduce Speed and Length of Moves

Auto DP at Worksite Wait 30 Minutes to Build the Model

Figure 10.3 ÂŠ Marine Institute School of Maritime Studies 2014

B A

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Additional position references will be deployed as required during the approach to the platform. Client/company/field/ vessel requirements as well as industry practice will dictate the number of position reference systems required for a particular job. The vessel might be set up on DP using a minimum number or references (perhaps only DGPS) due to system availability. HPR beacons deployed at the setup location might be out of range at the worksite. Taut wires will have to be deployed closer to the worksite because of wire angle limitations. If HPR and/or taut wire are required references during approach they may be walked along using a series of replumbs when beacon distance (HPR) or angle (taut wire) limits are reached. The Artemis fix station, Fanbeam reflector or RADius transponder may not be visible from the setup location or perhaps they have to be transferred from the vessel to the platform when closer in. The minimum number of required references for a given stage of the operation should always be deployed. Standby references, if available, should be ready if one fails. Using more than the minimum required references is good practice. The greater number of good quality references online, the less chance that the failure of one will have a serious influence on vessel positioning capability. Deploying references with possible common mode failures should be avoided. Two DGPS systems using the same receiving antenna or using a common software package are subject to single point failures. Three HPR beacons used in SSBL mode are subject to single point failure from a single subsea noise source. During the approach a visual lookout should be kept both as a check of vessel progress and to alert the DP operator to unforeseen problems which might develop. This might be due to supplied worksite information being insufficient (i.e. a helideck or flare tower which is not on the plans). It could be crane operations which have the crane swinging loads over the worksite. There may be unreported vessel traffic in the area or reported vessels that are not where they are supposed to be. Vessel progress may also be monitored on an electronic chart/survey spread (if fitted). Care should be taken that the information displayed is accurate and up to date.

Worksite Setup The mathematical model is constantly updated from the point that the vessel is under manual control at the DP console. The optimum mathematical model is achieved when the vessel is stopped at one location. After arriving at the worksite the vessel should be allowed to settle for at least 30 minutes to allow the mathematical model to update fully. Before a green light is given to commence operations (diving, ROV, pipelay, etc.) the following have to be considered: »» Has the vessel model had sufficient time to build at this location? »» Note position/heading deviations and determine if there are within acceptable limits for the operation to be conducted. »» Ensure that gain settings are appropriate for the conditions. »» Ensure that sufficient reference systems are online and that their performance has been checked and found to be acceptable. »» Vessel capability and redundancy must be reconfirmed. »» Check wind sensors to ensure proper selection and that readings reflect actual wind. Readings that were correct away from the platform may now have induced errors caused by wind interaction with the platform structure. »» Recheck gyro and magnetic compass readings. »» Review and analyze any DP system alarms. »» Complete applicable checklist. When all checks have been completed and all is in readiness (with regard to DP) a “green light” can be given for operations to commence.

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Conducting Operations While the DP operation is underway the vessel may be stopped at one location or moving as per the requirements of the job. The DPO is to monitor the DP system and ensure that operations are conducted in a safe and efficient manner. Any required heading or position moves while on DP, are to be conducted at a speed that is safe for the operation at hand (moving at 3 knots with an ROV in the water that has a maximum speed of 2 knots is not acceptable). A 5m move to port with the same 1 knot speed that was used a short time ago for a 500m move straight ahead might result in a 5m overshoot past the setpoint, in addition to large amounts of thrust required to start and stop the vessel as well as settle it down on the new position. A rate of turn which is beyond the turning capability of the vessel in the present conditions may result in the system putting so much effort into the heading change that the vessel drifts off position (system priority on heading). The required levels of redundancy must be maintained at all times. Without redundancy the vessel is subject to loss of position if a fault in a critical component fails. When lack of redundancy is detected the DPO should take immediate action to correct the problem. This might involve starting extra generators or thrusters. It could involve changing the position or heading of the vessel. Stopping the operation at hand and moving the vessel to a safe location may be the appropriate action, if redundancy cannot be regained. Example: A Class 2 dive support vessel with divers deployed has a partial blackout. The bus is split and half the vessels power supply is still available. Adequate redundancy was available prior to the failure and the vessel maintains station. Divers should be immediately recalled to the bell and recovered until such time as the problem can be fixed. The job is almost finished and the divers only require a “few” minutes to collect their tools. The vessel will then be free to proceed to the next job location. A decision (incorrect) is made to allow the divers to collect their tools and during those “few” minutes more problems develop which result in a further loss of power. Unable to hold station, the vessel drifts, dragging the divers with it. Successful recovery of the divers is now largely based on good luck. Hopefully they can get safely back to the bell and recover to deck before they or the bell become entangled in subsea obstructions located in the area. Obstructions that were at a safe distance when the vessel was on station with full redundancy now become a hazard to the divers.

Vessel performance (heading & position) must be constantly monitored to ensure that deviations stay within acceptable limits. Gain settings may have to be altered to take into account changes in environmental conditions. Monitoring and controlling vessel’s motion (i.e. changing heading to reduce rolling) may be required for some jobs. This might include reducing rolling when heavy loads are moved on deck using the vessel’s crane, launching an ROV over the side or limiting motion to the point where a helicopter is able to land. All alarms are to be investigated and action taken as appropriate to correct any problems indicated by the alarms. Position references are to be monitored on an ongoing basis to ensure correct operation and action taken to ensure that the minimum number of required references, are always online. Power consumption is monitored and generators not required may be shut down to save on fuel. Thrusters not required may also be shut down to save on equipment wear. Any shutdowns should be made taking into consideration the required level of capability and redundancy.

Worksite Departure When the job is completed the vessel will switch from DP to manual control and steam to the next jobsite or port as required. If the vessel is working in open water with no obstructions nearby the switching procedure can be followed and the vessel can steam away. If the vessel is located close to an obstacle (such as a platform) it should be moved to a safe distance under DP control before going to manual mode. Safe distance will depend on weather conditions and on the skill of the DPO to control the vessel in manual mode. © Marine Institute School of Maritime Studies 2014

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Example: A vessel is 20m from the side of a platform. Subsea operations are complete and the vessel is clear in all respects to depart. The vessel is switched to joystick mode by the DPO with the intention of moving away under manual control. Shortly afterwards the vessel strikes the platform, maybe due to the DPO not having adequate knowledge of the operating characteristics of the vessel in joystick mode (lack of practice). Perhaps he initially pushed the joystick the wrong way (lack of system knowledge) and could not correct for the mistake in time. Possibly environmental conditions were such that switching from computer to manual at such close proximity (irrespective of operator skill) was simply not advisable.

Before departing from the work location checks must be completed to ensure that all is in readiness for the departure. The subsea work might be completed but the diving bell might not yet be back onboard. Lines used to transfer tools to the divers on the bottom may not be completely out of the water. The ROV might not be back on deck and secured. Crane operations might be ongoing that would be adversely affected by a change in vessel heading as it steams away from location. Vessel position references will have to be recovered depending on type in use (Artemis fix station, Fanbeam reflector/s, HPR beacons or Taut Wire, etc.). However, sufficient references must remain online until the vessel is ready to switch out of DP mode. HPR poles must be retracted before vessel speed rises to the point where they could be damaged.

Manning The DP desk should be manned at all times while the vessel is under DP control. The majority of DP operations are conducted with at least two DP operators on the bridge or manning the DP control room. For some operations that require no redundancy (i.e. vessel using DP to follow an ROV doing a pipeline inspection in open water) there may be only one DPO on watch at a time. When two DPOs are present, one should be totally dedicated to the DP console and the DP operation. The other would carry out other bridge duties (i.e. radar/visual lookout, non DP communications, issue of work permits, etc.). The two DPOs should normally alternate an hour on the desk and an hour off. Long periods of calm with little activity can occur during some DP operations. When DP operators are not required to make vessel moves and are not actively involved in the vessel’s operations, there is the possibility of lapses in concentration where the DPO is not fully aware of the status of the ongoing operation and of the current operation of the DP system. Alternating DPOs at the DP desk every hour will help to avoid this problem. It is equally important to change hourly when operations are more hectic as fatigue could become a problem over the course of a 12 hour watch. The DP control area should be free from distractions and influences which take the DPO’s attention away from the DP system (i.e. conversations carried out by personnel having nothing to do with the ongoing operation).

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Watch Handover Before taking over a DP watch, the DPO must be fully aware of all aspects of the operation. If there are 2 DPOs on a watch it would be good practice not to have both change watch at the same time. If the 4 DPOs on the vessel are doing 12 hour watches, watches could be changed at 0600, 1200, 1800 and 2400. This would mean that at least 1 DPO would always be on the bridge who has current knowledge of the situation (having come on watch 6 hours previous). Information to be passed over by the departing DPO and obtained by the one coming on watch would vary depending on the operation but would include the following: »» What is the status of the operation (i.e. Diving Operations: Are the divers down? What is the current position of the divers? What are they doing? What their future plans? etc. Pipe Lay: What is the planned route? What vessel speed is being used? Is the vessel currently moving or stopped? etc.)? »» How has the DP system been performing and have there been any problems? »» How is the DP console set up (DP mode selected, gain settings, screen options, etc.). »» What position references are in use and how have they been performing? »» Are all thrusters/propellers/ rudders available and how are they performing? »» What is the situation regarding power supply? »» Is the vessel meeting redundancy requirements (if applicable)? »» What are the current weather conditions and what is the latest forecast? »» What is the DP current and how has it changed over the course of the watch? »» What has been the position keeping performance of the vessel? »» Are there any new orders, notices to mariners, etc., of which the DPO coming on watch is unaware? The DPO coming on watch should complete a checklist to gain situational awareness regarding DP system settings and current system performance.

Logs A log must be kept of all aspects of the DP operation. All required information may not be recorded on the printer/s connected to the DP system. Information manually logged would include but not be limited to the following: »» Times of starting and stopping DP operations as well as significant events during the operation. (i.e. time ROV was off deck, time diving bell left the surface, time shuttle tanker disconnects from loading buoy, times for temporary stop of loading crude due to weather, etc.) »» Any operator input changes of heading or position while on DP. »» Deploying or recovering of position references. »» Starting or stopping of thrusters or generators. »» Any problems encountered with the DP system. »» Changes in system status with regard to redundancy/vessel capability. »» Movements of other vessels in the area. Logs can provide a record of evens to be referred to during the investigation of an accident. Times of starting and stopping DP operations may be used to settle financial disputes with charterers. Records of encountered problems may help technicians when repairing the DP system. These are some of the uses of the information recorded in the DP log. Some DP systems provide the ability to save trend graphs to disk for future reference. A DP system with a data logger function may save system operation and status information to an external computer for future reference. © Marine Institute School of Maritime Studies 2014

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DP Printers An aid to accurate log keeping are print outs from the DP system. An example of a DP system print out is shown following. This is a print out from a shuttle tanker equipped with two bow thrusters, two main props, and two rudders. A A A A A A A Alarm A Alarm A Alarm A Alarm A A A Alarm Alarm A Alarm A A Alarm A A Alarm A A A A A Alarm A A Alarm A A A A Alarm A A Alarm A Alarm A A Alarm A Alarm A Alarm A Alarm A A A A Alarm A A 10-26

12:42:33 12:42:33 12:42:37 12:42:52 12:43:10 12:43:10 12:43:32 12:43:32 12:43:32 12:43:32 12:43:45 12:43:45 12:44:00 12:44:02 12:44:27 12:44:27 12:44:27 12:44:30 12:44:35 12:44:38 12:44:38 12:44:49 12:44:49 12:45:10 12:45:10 12:45:33 12:46:31 12:46:33 12:46:40 12:46:47 12:46:47 12:47:08 12:47:08 12:47:35 12:47:45 12:48:10 12:48:10 12:48:16 12:48:16 12:48:56 12:49:47 12:49:47 12:50:00

17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17

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SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP SEP

2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012 2012

Current CP position E 671114.3 N 5179077.2 SIMRAD (10) PME selected Set Heading = 50.0 degrees Set Heading = 49.9 degrees Current CP osition E 669114.5 N 5179007.1 SIMRAD (11) PME selected Thruster 1 high thrust warning Thruster 2 high thrust warning Stbd Main Prop high thrust warning Port Main Prop high thrust warning Stbd Main Prop high thrust warning OK Port Main Prop high thrust warning OK Con. analysis: Thruster failure critical Con. analysis: Bus section failure critical SIMRAD (10) PME failed Current CP position E 671113.1 N 5179077.6 SIMRAD (10) PME deselected Mismatch between PME/sensor selections Mismatch between PME/sensor selections OK Thruster 1 high thrust warning OK Thruster 2 high thrust warning OK Current CP position E 671114.6 N 5179077.4 ARTEMIS PME selected Thruster 1 high thrust warning Thruster 2 high thrust warning Set Heading = -4.2 degrees Con. analysis: Bus section failure not critical Con. analysis: Thruster failure not critical Offloading position warning Thruster 1 high thrust warning OK Thruster 2 high thrust warning OK Stbd Main Prop high thrust warning Port Main Prop high thrust warning Con. analysis: Thruster failure critical Con. analysis: Bus section failure critical Thruster 1 pitch feedback fault Thruster 2 pitch feedback fault Thruster 1 pitch feedback OK Thruster 2 pitch feedback OK No Push-Pull mode selected Anemometer 1 failed Anemometer 1 deselected Console B selected ÂŠ Marine Institute School of Maritime Studies 2014

Notes

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Chapter 11 GUIDANCE and REGULATION

ÂŠ Marine Institute School of Maritime Studies 2014

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Guidance and Regulation A number of organizations have taken DP into their guidelines/regulations and other documents dealing with the safety and efficiency of offshore operations.

IMO The International Maritime Organization (IMO) has published “Guidelines for Vessels with Dynamic Positioning Systems” (MSC/Circ. 645). These guidelines were developed to provide an international standard for dynamic positioning on all types of vessels. The IMO guidelines are found in APPENDIX 1 of this manual. Classification societies have used these IMO guidelines as the basis for developing their own rules for the classification of DP vessels.

Administrations Governments can set regulations regarding the operation of DP vessels within their areas of jurisdiction. However, administrations have largely left the regulation of DP up to industry itself. The Norwegian Maritime Authority (NMA) in Norway is one example of a government body that does produce regulation for industry to follow. As the DP industry continues to grow, administrations may take a more active role in the regulation of DP.

Classification Societies The various classification societies involved with the certification of DP vessels also have rules and regulations governing equipment required on DP vessels. Companies have to ensure that their vessels comply with the rules of the classification societies in order to receive a DP Class designation. Some examples of class rules: Lloyds Register of Shipping (LRS): “Rules and Regulations for the Classification of Ships, Part 7, Chapter 4, Dynamic Positioning Systems “ American Bureau of Shipping (ABS) : “Guide for Dynamic Positioning Systems” Det Norske Veritas (DNV): “Rules for Classification of Ships, Part 6, Chapter 7, Dynamic Positioning Systems” These are just 3 examples. A list of the different classification societies and their various DP designations is found in APPENDIX II of this manual.

Industry Organizations Industry has various organizations that produce guidance relating to DP and DP operations. Some examples: The International Marine Contractors Association (IMCA) is an international trade association representing companies and organizations engaged in delivering offshore, marine and underwater solutions. It was formed in 1995 from the amalgamation of the International Association of Underwater Engineering Contractors (AODC) and the Dynamic Positioning Vessel Owners Association (DPVOA). and has members from countries worldwide. IMCA membership includes vessel owners, managers, and operators. It has developed guidelines for the design and operation of various types of DP vessels. Various publications regarding DP operations are available from IMCA, many available online.

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The Dynamic Positioning Committee of the Marine Technology Society (MTS) has a mission to encourage exchange of information, discussion of technology, training and education, foster improvement of DP reliability, develop guidelines, and address any other issues pertinent to dynamic positioning that facilitate incident free execution of DP operations, and that are consistent with the objectives of the Marine Technology Society. The DP Committee was established in 1996, with the objective of promoting a greater international understanding of Dynamic Positioning and related issues. MTS also produces guidance regarding DP operations, made available online. Individual companies such as Shell UK Exploration and Production, Hibernia Management and Development, Statoil, etc., may produce their own guidelines with regard to DP operations being conducted for their respective companies.

DPO Training Requirements Section B of the STCW (Standards of Training Competence and Watchkeeping) code, provides guidelines for the training of DP operators. As the guidelines are in Part B of the code, they are voluntary. Should, at some point in time, the guidelines be moved to part A of the code, administrations would be required to make DP training mandatory. Currently, the training requirements for DP operators are mainly governed by industry requirements. Currently, that training for industry is provided mainly under the training scheme administered by the Nautical Institute in the United Kingdom. IMCA also has a set of guidelines regarding DP training, “The Training and Experience of Key DP Personnel”. The guidelines are more in depth but the training regime recommended is similar to that of the Nautical Institute and the Norwegian Maritime Directorate.

FMEA A Failure Mode Effects Analysis (FMEA) is a document containing a detailed description of a vessels DP and associated systems and the results of failures within those systems. The FMEA document is provided subsequent to a thorough audit, and is often a requirement of the vessel’s classification society notation for DP Equipment Class. The FMEA document must be revalidated at regular intervals. The initial inspection has to be revalidated every 5 years, sooner if modifications are made to the DP system. FMEAs are required on Class 2 & 3 vessels. Note: During the course, a list of web links will be provided which relate to the guidance and regulation of DP.

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ÂŠ Marine Institute School of Maritime Studies 2014

Appendix 1

ÂŠ Marine Institute School of Maritime Studies 2014

Dynamic Positioning - Induction Student Handbook

Appendix 1-1

Notes

Appendix 1-2 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

Material from the IMO publication Guidelines for Vessels with Dynamic Positioning Systems, MSC/Circ. 645, is reproduced with the permission of the International Maritime Organization (IMO), which does not accept responsibility for the correctness of the material as reproduced: in case of doubt, IMOâ&#x20AC;&#x2122;s authentic text shall prevail. Reproduced from the IMO website, http://www.imo.org This document is published by the Maritime Safety Committee of the International Maritime Organization. It details the requirements for the provision of DP and associated systems, and details the levels of redundancy within Equipment Class.

INTERNATIONAL MARITIME ORGANIZATION MSC/Circ.645 6 June 1994 4 ALBERT EMBANKMENT LONDON SE1 7SR Telephone: 071 735-7611 Telegrams: INTERMAR-LONDON SE1 Telex: 23588 Telefax: 071-587-3210

Ref. T4/3.03

GUIDELINES FOR VESSELS WITH DYNAMIC POSITIONING SYSTEMS

1. The Maritime Safety Committee at its sixty-third session (16 to 25 May 1994), approved the Guidelines for Vessels with Dynamic Positioning systems, set out at annex to the present circular, as prepared by the Sub-Committee on Ship Design and Equipment at its thirty-seventh session.

2. Member Governments are invited to bring the Guidelines to the attention of all bodies concerned, and apply the Guidelines to new vessels with dynamic positioning systems constructed on or before 1 July 1994, in conjunction with the implementation of the provisions of paragraph 4.12 of the 1989 MODU Code as amended by resolution MSC.38(63).

ember Governments are also invited to use the proposed model form of Flag State Verification and M Acceptance Document set out in the APPENDIX to the Guidelines.

***

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Dynamic Positioning - Induction Student Handbook

Appendix 1-3

MSC/Circ. 645

ANNEX GUIDELINES FOR VESSELS WITH DYNAMIC POSITIONING SYSTEMS Contents

Page

Preamble. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

General

1.1

Purpose and Responsibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2

Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3

Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.4

Exemptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.5

Equivalents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Equipment Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Functional Requirements

3.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.2

Power System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3.3

Thruster System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4

DP-Control System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4.1

General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4.2

Computers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.4.3 Position Reference Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.4.4

Vessel Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.5

Cable and Piping Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.6

Requirements for Essential non-DP-Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Operational Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Surveys, Testing, and the Flag State Verification and Acceptance Document (FSVK). . . . . . . . . . 11

5.1

Surveys and Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

5.2

Flag State Verification and Acceptance Document (FSVAD). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

APPENDIX: Model form of FSVAD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Appendix 1-4 Dynamic Positioning - Induction Student Handbook

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MSC/Circ. 645 ANNEX Page 2

PREAMBLE 1 These Guidelines for vessels with dynamic positioning systems have been developed to provide an international standard for dynamic positioning systems on all types of new vessels. 2 Taking into account that dynamically positioned vessels are moved and operated internationally and recognizing that the design and operating criteria require special consideration, the Guidelines have been developed to facilitate international operation without having to document the dynamic positioning system in detail for every new area of operation. 3 The Guidelines are not intended to prohibit the use of any existing vessel because its dynamic positioning system does not comply with these Guidelines. Many existing units have operated successfully and safely for extended periods of time and their operating history should be considered in evaluating their suitability to conduct dynamically positioned operations. 4

ompliance with the Guidelines will be documented by a Flag State Verification and Acceptance Document C (FSVAD) for the dynamic positioning system. The purpose of a FSVAD is to ensure that the vessel is operated, surveyed, and tested according to vessel specific procedures and that the results are properly recorded.

5 A coastal state may permit any vessel whose dynamic positioning system is designed to a different standard than that of these Guidelines to engage in operations.

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Appendix 1-5

MSC/Circ. 645 ANNEX Page 3 1

GENERAL

1.1

Purpose and responsibility

1.1.1 The purpose of these Guidelines is to recommend design criteria, necessary equipment, operating requirements, and a test and documentation system for dynamic positioning systems to reduce the risk to personnel, the vessel, other vessels or structures, sub-sea installations, and the environment while performing operations under dynamic positioning control.

1.1.2 The responsibility of ensuring that the provisions of the Guidelines are complied with rests with the owner of the DP-vessel.

1.2 Application The Guidelines apply to dynamically positioned units or vessels, the keel of which is laid or which is at a similar stage of construction on or after 1 July 1994. 1.3

Definitions In addition to the definitions in the MODU Code 1989, the following definitions are necessary for the guidelines:

1.3.1 Dynamically positioned vessel (DP-vessel) means a unit or a vessel which automatically maintains its position (fixed location or predetermined track) exclusively by means of thruster force.

1.3.2 Dynamic positioning system (DP-vessel) means the complete installation necessary for dynamically positioning a vessel comprising the following sub-sea systems:

.1 power system, .2 thruster system, and .3 DP-control system.

1.3.3 Position keeping means maintaining a desired position within the normal excursions of the control system and the environmental conditions.

1.3.4 Power system means all the components and systems necessary to supply the DP-system with power. The power system includes:

.1 prime movers with necessary auxiliary systems including piping, .2 Generators, .3 switchboards, and .4 distributing system (cabling and cable routing).

1.3.5 Thruster system means all components and systems necessary to supply the DP-system with thrust force and direction. The thruster system includes:

.1 thrusters with drive units and necessary auxiliary systems including piping, .2 main propellers and rudders if these are under the control of the DP-system, Appendix 1-6 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

MSC/Circ. 645 ANNEX Page 4 .3 thruster control electronics, .4 manual thruster controls, and .5 associated cabling and cable routing.

1.3.6 DP-control system means all control components and systems, hardware, and software necessary to dynamically position the vessel. The DP-control system consists of the following:

.1 computer system/joystick system, .2 sensor system .3 display system (operator panels), .4 position reference system, and .5 associated cabling and cable routing.

1.3.7 Computer system means a system consisting of one or several computers including software and their interfaces.

1.3.8 Redundancy means ability of a component or system to maintain or restore its function, when a single failure has occurred. Redundancy can be achieved for instance by the installation of multiple components, systems or alternative means of performing a function.

1.3.9

lag State Verification and Acceptance Document (FSVAD) means the document issued by the F Administration to a DP-vessel complying with these Guidelines (See APPENDIX for model form.).

1.4 Exemptions An Administration may exempt any vessel which embodies features of a novel kind from any provisions of the guidelines the application of which might impede research into the development of such features. Any such vessels should, however, comply with safety requirements which, in the opinion of the Administration, are adequate for the service intended and are such as to ensure the overall safety of the vessel. The Administration which allows any such exemptions should list the exemptions on the Flag State Verification and Acceptance Document (FSVAD) and communicate to the Organization the particulars, together with the reason therefore, so that the Organization may circulate the same to other governments for the information of their officers. 1.5

Equivalents

here the Guidelines require that a particular fitting, material, appliance, apparatus, item of equipment W or type thereof should be fitted or carried out in a vessel, or that any particular provision should be made, or any procedure or arrangement should be complied with, the Administration may allow other fitting, material, appliance, apparatus, item of equipment or type thereof to be fitted or carried, or any other provision, procedure or arrangement to be made in that vessel, if it is satisfied by trial thereof or otherwise that such fitting, material, appliance, apparatus, item of equipment or type thereof or that any particular provision, procedure or arrangement is at least as effective as that required by the Guidelines.

1.5.1

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Appendix 1-7

MSC/Circ. 645 ANNEX Page 5

1.5.2

hen an Administration so allows any fitting, material, appliance, apparatus, item of equipment or type W thereof, or provision, procedure, arrangement, novel design or application to be substituted, it should communicate to the Organization the particulars thereof, together with a report on the evidence submitted, so that the Organization may circulate the same to other Governments for information of their officers.

EQUIPMENT CLASSES

DP-system consists of components and systems acting together to achieve sufficiently reliable position A keeping capability. The necessary reliability is determined by the consequence of a loss of position keeping capability. The larger the consequence, the more reliable the DP-system should be.

2.1

To achieve this philosophy, the requirements have been grouped into three equipment classes. For each equipment class, the associated worst case failure should be defined as in 2.2 below. The equipment class of the vessel required for a particular operation should be agreed between the owner of the vessel and the customer based on a risk analysis of the consequence of a loss of position. Else, the Administration or coastal State may decide the equipment class for the particular operation.

2.2

The equipment classes are defined by their worst case failure modes as follows:

.1 For equipment class 1, loss of position may occur in the event of a single fault. .2 For equipment class 2, a loss of position is not to occur in the event of a single fault in any active component or system. Normally, static components will not be considered to fail where adequate protection from damage is demonstrated, and reliability is to the satisfaction of the Administration. Single failure criteria include: .1 Any active component or system (generators, thrusters, switchboards, remotecontrolled valves, etc.). .2 Any normally static component (cables, pipes, manual valves, etc.) which is not properly documented with respect to protection and reliability.

For equipment class 3, a single failure includes:

.1 Items listed above for class 2, and any normally static component is assumed to fail.

.2 All components in any one watertight compartment, from fire or flooding.

.3 All components in any one fire sub-division, from fire or flooding (For cables, see also 3.5.1.).

2.3 For equipment classes 2 and 3, a single inadvertent act should be considered as a single fault if such an act is reasonably probable.

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MSC/Circ. 645 ANNEX Page 6

2.4

ased on the single failure definitions in 2.2, the worst case failure should be determined and used as the B criterion for the consequence analysis (See 3.4.2.4.).

2.5 The Administration should assign the relevant equipment class to a DP-vessel based on the criteria in 2.2 and state it in the Flag State Verification and Acceptance Document (FSVAD) (See 5.2.).

2.6 When a DP-vessel is assigned an equipment class, this means that the DP-vessel is suitable for all types of DP-operations within the assigned and lower equipment classes.

2.7 It is a provision of the guidelines that the DP-vessel is operated in such a way that the worst case failure, as determined in 2.2, can occur at any time without causing a significant loss of position.

FUNCTIONAL REQUIREMENTS

3.1

General

3.1.1 In so far as is practicable, all components in a DP-system should be designed, constructed, and tested in accordance with international standards recognized by the Administration.

3.1.2 In order to meet the single failure criteria given in 2.2, redundancy of components will normally be necessary as follows:

.1 for equipment class 2, redundancy of all active components; .2 for equipment class 3, redundancy of all components and physical separation of the components.

3.1.3 For equipment class 3, full redundancy may not always be possible (e.g., there must be a need for a single change-over system from the main computer system to the back-up computer system). Nonredundant connections between otherwise redundant and separated systems may be accepted provided that it is documented to give clear safety advantages, and that their reliability can be demonstrated and documented to the satisfaction of the Administration. Such connections should be kept to the absolute minimum and made to fail to the safest condition. Failure in one system should in no case be transferred to the other redundant system.

3.1.4 Redundant components and systems should be immediately available and with such capacity that the DP-operation can be continued for such a period that the work in progress can be terminated safely. The transfer to redundant component or system should be automatic as far as possible, and operator intervention should be kept to a minimum. The transfer should be smooth and within acceptable limitations of the operation.

3.2

Power system

3.2.1

The power system should have an adequate response time to power demand changes.

3.2.2

For equipment class 1, the power system need not be redundant.

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Dynamic Positioning - Induction Student Handbook

Appendix 1-9

MSC/Circ. 645 ANNEX Page 7

3.2.3 For equipment class 2, the power system should be divisible into two or more systems such that in the event of failure of one system at least one other system will remain in operation. The power system may be run as one system during operation, but should be arranged by bus-tie breakers to separate automatically upon failures which could be transferred from one system to another, including overloading and short-circuits.

3.2.4 For equipment class 3, the power system should be divisible into two or more systems such that in the event of failure of one system, at least one other system will remain in operation. The divided power system should be located in different spaces separated by A.60 class division. Where the power systems are located below the operational waterline, the separation should also be watertight. Bus-tie breakers should be open during equipment class 3 operations unless equivalent integrity of power operation can be accepted according to 3.1.3.

3.2.5

3.2.6 If a power management system is installed, adequate redundancy or reliability to the satisfaction of the Administration should be demonstrated.

3.3

or equipment classes 2 and 3, the power available for position keeping should be sufficient to maintain F the vessel in position after worst case failure according to 2.2.

Thruster system

3.3.1 The thruster system should provide adequate thrust in longitudinal and lateral directions, and provide yawing moment for heading control.

3.3.2 For equipment classes 2 and 3, the thruster system should be connected to the power system in such a way that 3.3.1 can be complied with even after failure of one of the constituent power systems and the thrusters connected to that system.

3.3.3 The values of thruster force used in the consequence analysis (See 3.4.2.4.) should be corrected for interference between thrusters and other effects which would reduce the effective force.

3.3.4 Failure of thruster system including pitch, azimuth or speed control, should not make the thruster rotate or go to uncontrolled full pitch and speed.

3.4

DP-control system

3.4.1 General .1 In general, the DP-control system should be arranged in a DP-control station where the operator has a good view of the vesselâ&#x20AC;&#x2122;s exterior limits and the surrounding area. .2 The DP-control station should display information from the power system, thruster system, and DPcontrol system to ensure that these systems are functioning correctly. Information necessary to operate the DP-system safely should be visible at all times. O ther information should be available upon operator request. .3 Display systems and the DP-control station in particular, should be based on sound ergonometric principles. The DP-control system should provide for easy selection of c ontrol mode, i.e., manual, joystick, or computer control of thrusters, and, in the active m ode, should be clearly displayed. Appendix 1-10 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

MSC/Circ. 645 ANNEX Page 8 .4 For equipment classes 2 and 3, operator controls should be designed so that no single inadvertent act on the operators’ panel can lead to a critical condition. .5 Alarms and warnings for failures in systems interfaced to and/or controlled by the DP-control system are to be audible and visual. A permanent record of their occurrence and of status changes should be provided together with any necessary explanations. .6 The DP-control system should prevent failures being transferred from one system to another. The redundant components should be so arranged that a failure of one component should be isolated, and the other component activated. .7 It should be possible to control the thrusters manually, by individual joysticks and by a common joystick, in the event of failure of the DP-control system. .8 The software should be produced in accordance with an appropriate international quality standard recognized by the Administration. 3.4.2 Computers .1 For equipment class 1, the DP-control system need not be redundant. .2 For equipment class 2, the DP-control system should consist of at least two independent computer systems. Common facilities such as self-checking routines, data transfer arrangements, and plant interfaces should not be capable of causing the failure of both/all systems. .3 For equipment class 3, the DP-control system should consist of at least two independent computer systems with self-checking and alignment facilities. Common facilities such as self-checking routines, data transfer arrangements and plant interfaces should not be capable of causing failure at both/all systems. In addition, one back-up DP-control system should be arranged, see 3.4.2.6. An alarm should be initiated if any computer fails or is not ready to take control. .4 For equipment classes 2 and 3, the DP-control system should include a software function, normally known as ‘consequence analysis’, which continuously verifies that the vessel will remain in position even if the worst case failure occurs. This analysis should verify that the thrusters remaining in operation after the worst case failure can generate the same resultant thruster force and moment as required before the failure. The consequence analysis should provide an alarm if the occurrence of a worst case failure would lead to a loss of position due to insufficient thrust for the prevailing environmental conditions. For operations which will take a long time to safely terminate, the consequence analysis should include a function which simulates the thrust and power remaining after the worst case failure, based on manual input of weather trend.

Dynamic Positioning - Induction Student Handbook

Appendix 1-11

MSC/Circ. 645 ANNEX Page 9

.5 Redundant computer systems should be arranged with automatic transfer of control after a detected failure in one of the computer systems. The automatic transfer of control from one computer system to another should be smooth, and within the acceptable limitations of the operation.

.6 For equipment class 3, the back-up DP-control system should be in a room separated by A.60 class division from the main DP-control station. During DP-operation this back-up control system should be continuously updated by input from the sensors, position reference system, thruster feedback, etc., and be ready to take over control. The switch-over of control to the back-up system should be manual, situated on the back-up computer and should not be affected by failure of the main DP-control system. .7 An uninteruptable power supply (UPS) should be provided for each DP-computer system to ensure that any power failure will not affect more than one computer. UPS battery capacity should provide a minimum of 30 minutes operation following a mains supply failure. 3.4.3

Position reference systems

.1 Position reference systems should be selected with due consideration to operational requirements, both with regard to restrictions caused by the manner of deployment and the expected performance in a working situation. .2 For equipment classes 2 and 3, at least three position reference systems should be installed and simultaneously available to the DP-control system during operation. .3 When two or more position reference systems are required, they should not all be of the same type, but based on different principles and suitable for the operating conditions. .4 The position reference systems should produce data with adequate accuracy for the intended DPoperation. .5 The performance of position reference systems should be monitored and warnings provided when the signals from the position reference systems are either incorrect or substantially degraded. .6 For equipment class 3, at least one of the position reference systems should be connected directly to the back-up control system and separated by A.60 class division from the other position reference systems. 3.4.4

Vessel sensors

.1 Vessel sensors should at least measure vessel heading, vessel motions, and wind speed and direction. .2 When an equipment class 2 or 3 DP-control system is fully dependent on correct signals from vessel sensors, then these signals should be based on three systems serving the same purpose (i.e., this will result in at least three gyro compasses being installed). .3 Sensors for the same purpose, connected to redundant systems should be arranged independently so that failure of one will not affect the others. .4 For equipment class 3, one of each type of sensors should be connected directly to the back-up control system and separated by A.60 class division from the other sensors.

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ÂŠ Marine Institute School of Maritime Studies 2014

MSC/Circ. 645 ANNEX Page 10 3.5

Cables and piping systems

3.5.1 For equipment class 3, cables for redundant equipment or systems should not be routed together through the same compartments. Where this is unavoidable such cables could run together in cable ducts of A-60 class, the termination of the ducts included, which are effectively protected from all fire hazards, except that represented by the cables themselves. Cable connection boxes are not allowed in such ducts.

3.5.2 For equipment class 2, piping systems for fuel, lubrication, hydraulic oil, cooling water, and cables should be located with due regard to fire hazards and mechanical damage.

3.5.3 For equipment class 3, redundant piping system (i.e., piping for fuel, cooling water, lubrication oil, hydraulic oil, etc.) should not be routed together through the same compartments. Where this is unavoidable, such pipes could run together in ducts of A-60 class, the termination of the ducts included, which are effectively protected from all fire hazards, except that represented by the pipes themselves.

3.6 Requirements for essential non-DP-systems For equipment classes 2 and 3, systems not directly part of the DP-system but which in the event of failure could cause failure of the DP-system, (e.g., common fire suppression systems, engine ventilation systems, shut-down systems, etc.), should also comply with relevant requirements of these Guidelines. 4

OPERATIONAL REQUIREMENTS

4.1

efore every DP-operation, the DP-system should be checked according to a vessel specific “location” B check list to make sure that the DP-system is functioning correctly and that the system has been set up for the appropriate equipment class.

4.2

uring DP-operations, the system should be checked at regular intervals according to a vessel specific D watchkeeping checklist.

4.3 DP operations necessitating equipment class 2 or 3 should be terminated when the environmental conditions are such that the DP-vessel will no longer be able to keep position if the single failure criterion applicable to the equipment class should occur. In this context, deterioration of environmental conditions and the necessary time to safely terminate the operation should also be taken into consideration. This should be checked by way of environmental envelopes if operating in equipment class 1 and by way of an automatic consequence analysis if operating in equipment class 2 or 3. The necessary operating instructions, etc., should be on board.

4.4 The following checklists, test procedures, and instructions should be incorporated into the DP operating manuals for the vessel:

.1 Location checklist (See 4.1.) .2 Watchkeeping checklist (See 4.2.) .3 DP-operation instructions (See 4.3.) .4 Annual tests and procedures (See 5.1.1.3.) .5 Initial and periodical (5-year) tests and procedures (See 5.1.1.1 and 5.1.1.2.)

.6 Example of tests and procedures after modifications and non-conformities (See 5.1.1.4.)

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Appendix 1-13

MSC/Circ. 645 ANNEX Page 11 5 SURVEYS, TESTING, AND THE FLAG STATE VERIFICATION AND ACCEPTANCE DOCUMENT (FSVAD)

5.1

Surveys and testing

5.1.1 Each DP-vessel which is required to comply with the Guidelines is subject to the surveys and testing specified below:

.1 Initial survey which should include a complete survey of the DP-system to ensure full compliance with the applicable parts of the Guidelines. Further, it includes a complete test of all systems and components and the ability to keep position after single failures associated with the assigned equipment class. The type of test carried out and results should be documented in the Flag State Verification and Acceptance Document (FSVAD) (See 5.2).

.2 P eriodical survey at intervals not exceeding five years to ensure full compliance with the applicable parts of the Guidelines. A complete test should be carried out as required in 5.1.1.1. The type of test carried out and the results should be documented in the FSVAD (See 5.2).

.3 annual survey should be carried out within three months before or after each anniversary date of the initial survey. The annual survey should ensure that the DP-system has been maintained in accordance with applicable parts of the guidelines and is in good working order. Further an annual test of all important systems and components should be carried out to document the ability of the DP-vessel to keep position after single failures associated with the assigned equipment class. The type of test carried out and results should be documented in the FSVAD (See 5.2.). .4 A survey either general or partial according to circumstances should be made every time a defect is discovered and corrected or an accident occurs which affects the safety of the DP-vessel, or whenever any significant repairs or alterations are made. After such a survey, necessary tests should be carried out to demonstrate full compliance with the applicable provisions of the Guidelines. The type of tests carried out and results should be recorded and kept on board. 5.1.2

hese surveys and tests should be witnessed by officers of the Administration. The Administration may, T however, entrust the surveys and testing either to surveyors nominated for the purpose or to organizations recognized by it. In every case, the Administration concerned should fully guarantee the completeness and efficiency of the surveys and testing. The Administration may entrust the owner of the vessel to carry out annual and minor repair surveys according to a test programme accepted by the Administration.

5.1.3

fter any survey and testing has been completed, no significant change should be made to the DP-system A without the sanction of the Administration, except the direct replacement of equipment and fittings for the purpose of repair or maintenance.

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MSC/Circ. 645 ANNEX Page 12 5.2

Flag State Verification and Acceptance Document (FSVAD)

5.2.1

Flag State Verification and Acceptance Document (FSVAD) should be issued, after survey and testing A in accordance with these Guidelines, either by officers of the Administration or by an organization duly authorized by it. In every case, the Administration assumes full responsibility for the FSVAD.

5.2.2

he FSVAD should be drawn up in the official language of the issuing country and be that of the model T given in the appendix to the Guidelines. If the language used is neither English nor French, the text should include a translation into one of these languages.

5.2.3

The FSVAD is issued for an unlimited period, or for a period specified by the Administration.

5.2.4

n FSVAD should cease to be valid if significant alterations have been made in the DP-system A equipment, fittings, arrangements, etc., specified in the Guidelines without the sanction of the Administration, except the direct replacement of such equipment or fittings for the purpose of repair or maintenance.

5.2.5

n FSVAD issued to a DP-vessel should cease to be valid upon transfer of such a vessel to the flag of A another country.

5.2.6

The privileges of the FSVAD may not be claimed in favour of any DP-vessel unless the FSVAD is valid.

5.2.7 Control of a DP-vessel holding a valid FSVAD should be carried out according to the principles of 1.7 in the MODU Code 1989. 5.2.8

Results of the FSVAD tests should be readily available on board for reference.

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Appendix 1-15

MSC/Circ. 645 ANNEX Page 13 APPENDIX 1 Model Form of Flag State Verification and Acceptance Document FLAG STATE VERIFICATION AND ACCEPTANCE DOCUMENT (Official seal)

(State)

Issued under the provisions of the GUIDELINES FOR VESSELS WITH DYNAMIC POSITIONING SYSTEMS (MSC/Circ...) under the authority of the Government of ________________________________________ (full designation of the State) by ________________________________________________________________ (full official designation of the competent person or organization authorized by the Administration) Distinctive identification (Name or number)

Type

Port of registry

Official IMO-number

Date on which keel was laid or vessel was at similar stage of construction or on which major conversion was commenced _________________________________________________ THIS IS TO CERTIFY that the above-mentioned vessel has been duly documented, surveyed, and tested in accordance with the Guidelines for Vessels with Dynamic Positioning Systems (MSC/Circ......) and found to comply with the Guidelines. The vessel is allowed to operate in DP Equipment Class ______________ and in lower equipment classes. This document remains valid until _______________________________________ unless terminated by the Administration, provided that the vessel is operated, tested, and surveyed according to the requirements in the guidelines and the results are properly recorded. Issued at ___________________________________________________________________ (Place of issue of document) ____________ (Date of issue)

____________________________________________ (Signature of authorized official issuing the certificate)

______________________________________________________ (Seal or stamp of the issuing authority, as appropriate) Appendix 1-16 Dynamic Positioning - Induction Student Handbook

MSC/Circ. 645 ANNEX Page 14

LIST OF EXEMPTIONS AND EQUIVALENTS (ref. items 1.4 and 1.5 of the Guidelines)

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Appendix 1-17

MSC/Circ. 645 ANNEX Page 15

LIST OF MAIN SYSTEMS AND COMPONENTS COVERED BY FSVAD

_______________________________________ All main systems and components included in the dynamic positioning system are to be listed in a systematic way. As an alternative reference can be made to drawings, etc. It is important that it is possible by this list to identify all systems and components covered by FSVAD. Software versions should also be identified. Equipment installed after date of issuing FSVAD should only be included in the list after control and testing has been completed and modifications and nonconformities report signed.

Appendix 1-18 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

Record of annual survey reports, and special (5 years) survey reports Date

Test Type

Remarks

Report2 Reference Date/Number

Signature of appointed surveyor (IR)

_____________________________ 2

All reports should be filed together with this FVAD for use during later testing and inspections by nominated surveyors, flag State surveyors, etc. IR = if required, ref. Item 5.1.2

_____________________________ All main systems and components included in the dynamic positioning system are to be listed in a systematic way. As an alternative, reference can be made to drawings, etc. It is important that it is possible by this list to identify all systems and components covered by FSVAD. Software versions should also be identified. Equipment installed after the date of the issuing of the FSVAD should only be included in the list after control and testing has been completed and the modifications and non-conformities report signed.

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Appendix 1-19

Notes

Appendix 1-20 Dynamic Positioning - Induction Student Handbook

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Appendix 2

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Dynamic Positioning - Induction Student Handbook

Appendix 2-1

Notes

Appendix 2-2 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

DPS-2

DPS-3

CLASS 2

CLASS 3

DP-1

DP-2

DP-3

DYNAPOS AM/AT

DYNAPOS AM/AT R

DYNAPOS AM/AT RS

DYNAPOS DPS AUTRO 3

DYNAPOS DPS AUTR 2

DYNAPOS DPS AUT 1

DP 3

DP 2

DP 1

DYNAPOS DPS AUTS 0

DYNAPOS SAM

DPS-0

DPS-1

China Germanischer Classification Det Norske Veritas Lloyd Society

Bureau Veritas

DNV

American Bureau of Shipping

CCS

ABS

CLASS 1

IMO Equipment class KR LR

NK NMA

DP-3

DP-2

DP-1

DPS (3)

DPS (2)

DPS (1)

DP (AAA)

DP (AA)

DP (AM)

DP (CM)

Class C DP

Class B DP

Class A DP

DPS 3

DPS 2

DPS 1

DPS 0

Indian Register Lloyds Nippon Norwegian Register of Register Kaiji Maritime of Shipping of Kyokai Authority Shipping (Korea) Shipping

IRS

Russian Register of Shipping

DYNAPOS DYNAPOSAM/AT RS 3

DYNAPOS DYNAPOSAM/AT R 2

DYNAPOS DYNAPOSAM/AT 1

DYNAPOS SAM

Registro Italiano Navale

RINA

DP Class Notation

Dynamic Positioning - Induction Student Handbook

Appendix 2-3

CLASS 0: Minimum Requirements Subsystem or Component

ABS DPS-0

LRS DP (CM)

DNV DYNPOS-AUTS

Non-Redundant

Main Switchboard Bus - Tie Breaker Distribution Systems Power Management Thruster System Arrangement of Thrusters Auto Control Number of Control Computers Manual Control Independent Joystick with Auto Heading Single Levers for Each Thruster Position Reference Systems Ext. Sensors - Wind - Vertical Reference - Gyro

1 0 Non-Redundant No

Non-Redundant

Yes

1 0 1

1 1 1

UPS Alternate Control Station for Back-up Unit Printer for Registering and Explaining Alarms Consequence Analysis

Not Specified

Means of Permanently Recording Alarms

Yes

Power System Generators & Prime Movers

IMO No Designation

Appendix 2-4 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

CLASS 1: Minimum Requirements Subsystem or Component Power System Generators & Prime Movers Main Switchboard Bus - Tie Breaker Distribution Systems Power Management Thruster System Arrangement of Thrusters Auto Control Number of Control Computers Manual Control Independent Joystick with Auto Heading Single Levers for Each Thruster Position Reference Systems Ext. Sensors - Wind - Vertical Reference - Gyro UPS Alternate Control Station for Back-up Unit Printer for Registering and Explaining Alarms Consequence Analysis

IMO Class 1

ABS DPS-1

LRS DP (AM)

DNV AUT

Non-Redundant

1 0 Non-Redundant No

Non-Redundant

Yes

1 1 1

2 1 2

2 2 2

1 1 1

Yes

Not Specified

Means of Permanently Recording Alarms

Yes

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Appendix 2-5

CLASS 2: Minimum Requirements Subsystem or Component Power System Generators & Prime Movers Main Switchboard Bus - Tie Breaker Distribution Systems Power Management Thruster System Arrangement of Thrusters Auto Control Number of Control Computers Manual Control Independent Joystick with Auto Heading Single Levers for Each Thruster Position Reference Systems Ext. Sensors - Wind - Vertical Reference - Gyro UPS Alternate Control Station for Back-up Unit Printer for Registering and Explaining Alarms Consequence Analysis

IMO Class 2

ABS DPS-2

LRS DP (AA)

DNV AUTR

Redundant

1 1 Redundant Yes

Redundant

Yes

2 2/3 3

3 3 3

2 3 3

2 2/3 3

Yes

Not Specified

Means of Permanently Recording Alarms

Yes

Appendix 2-6 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014

CLASS 3: Minimum Requirements Subsystem or Component

IMO Class 3

ABS DPS-3

LRS DP (AAA)

DNV AUTRO

Power System Generators & Prime Movers

Redundant Separate Compartments

Main Switchboard

2 Separate Compartments 2 Normally Open

2 Separate Compartments

Redundant Separate Compartments

Yes

2 Separate Compartments Yes

Redundant Separate Compartments

3 1 at alternate control station

Yes

3 1 at alternate control station

2 (1 at alternate control station)

3 (1 at alternate control station)

2 (1 at alternate control station)

2/3 (1 at alternate control station)

3 (1 at alternate control station)

3 (1 at alternate control station) 3 1 at alternate control station

3 (1 at alternate control station)

3 1 at alternate control station

3 1 Required at alternate control station

3 1 at alternate control station

Yes

Not Specified

Means of Permanently Recording Alarms

Yes

Bus - Tie Breaker Distribution Systems

Power Management Thruster System Arrangement of Thrusters Auto Control Number of Control Computers Manual Control Independent Joystick with Auto Heading Single Levers for Each Thruster Position Reference Systems Ext. Sensors - Wind - Vertical Reference - Gyro UPS Alternate Control Station for Back-up Unit Printer for Registering and Explaining Alarms Consequence Analysis

Redundant Separate Compartments Yes

Dynamic Positioning - Induction Student Handbook

Appendix 2-7

Notes

Appendix 2-8 Dynamic Positioning - Induction Student Handbook

ÂŠ Marine Institute School of Maritime Studies 2014