Dyneema® in Rigging

Rigging engineered for extreme performance.

What is Dyneema®?

Dyneema® is the world’s strongest fiber™. Invented and manufactured by DSM Dyneema. It is a HMPE (High Modulus PolyEthylene) fiber made from UHMwPE (Ultra High Molecular Weight PolyEthylene). The extreme strength of the fiber is due to a unique gel spinning process, also developed by DSM Dyneema.

The result is a fiber which is 15 times stronger than steel on a weight-for-weight basis.

Besides having the best strength to weight ratio, Dyneema® offers excellent dynamic properties and is highly resistant to abrasion, bending fatigue, and environmental influences like UV radiation and salt water.

Therefore it’s no surprise that most demanding sailors competing in major regattas like the America’s Cup, Vendee’ Globe, and Volvo Ocean Race rely on yachting lines made with Dyneema®.

What do sailors want from their rigging?

Running rigging is an essential part for the overall performance of a yacht. Four principal characteristics define a rope’s quality and purpose. In competitive sailing, all these characteristics are engineered for maximum performance: • High strength at low weight: By maximizing strength and minimizing weight above the waterline, sailing performance can be greatly enhanced.

• Low stretch: This results in more control and less energy absorption. The force of the wind can be more efficiently converted into speed.

• Superior handling: Ropes need to run freely and flake smoothly, have a small diameter, not absorb water, be lightweight and easy to splice.

• Durability: High resistance to abrasion, chafing, bending fatigue, and environmental influences results in a reliable rig with long service life.

Why high strength at low weight?

A line needs to be strong enough to handle the loads, both static and dynamic (shock) that it will encounter during normal operation. For racing yachts, strength is even more important to ensure that the ropes will not fail under extreme conditions.

These boats are geared to save weight wherever possible. By reducing weight, especially in the mast, the center of gravity moves down towards the keel, improving the stability of the boat. The use of lines made of Dyneema® can effectively reduce weight in the mast, will strongly influence the boat’s behavior: the impact with the waves is less violent and the boat will lose less speed. On top of that, the boat heels less. This results in a larger used sail area giving more power and speed to the yacht.

20000 18000

Dyneema® (no cover)

16000

PBO core

strength (daN~Kg)

14000 12000

Steel wire Dyneema® core

10000

Fig. 1: The diagram shows strength vs. weight ratio of different yachting lines. NOTE: In a core/cover construction, the cover does not contribute to the maximum breaking load of the final rope, except in the case of PES, where the cover contributes up to 40% of the maximum breaking load.

LCP core

8000 6000

Aramid core

4000

PES core

2000 0 6

7

8

9

10

11

diameter (mm)

12

13

14

15

16

When comparing two halyards, one made of steel and the other one made with Dyneema® - both with maximum strength of approximately 3500 kg - the weight of the 8mm steel wire halyard will be over 6 times heavier compared to a halyard with a core made with Dyneema®. For example, a 30 meter halyard made with steel wire will weigh approximately 7.5 kg, compared to less than 1.3 kg for the same halyard containing Dyneema®.

A 12mm PES (polyester) halyard with the same breaking load weighs almost 3 kg. In addition, halyards made with Dyneema® can be partially stripped; the PES cover is removed, with exception of the areas around jammers and winches, saving an additional 20% weight on the halyard. Finally, Dyneema® does not absorb water.

Less water absorption means lighter rigging.

Why low elongation?

Elongation in running rigging is undesirable for several reasons. However, it is important to first distinguish the different aspects that cause elongation: 1. Setting of a rope 2. Stretch 3. Creep 1. Setting of a rope By putting a load on a rope it will pull the fibers in the most optimal way and eliminate the construction elongation.

This initial elongation is irreversible. It is possible to minimize the construction elongation by heat-setting or pre-stretching the rope before using it.

2. Stretch Stretch is the elastic elongation of a rope. That is, the rope will elongate under tension but returns to its initial length after the load is released. Every time a rope stretches due to a gust of wind, the sail loses its optimal ‘wing’ profile and the boat will not fully accelerate. In regattas, the slightest difference in sail trim determines winning or losing. Stretch in a sheet or halyard beyond its set position will compromise the control of the trimming position of the sails.

8000

PBO core

7000

6000

Dyneema® core

Load (daN ~ Kg)

5000

LCP core 4000

3000

Aramid core

PES core

2000

Fig. 2: The diagram shows the stretch of different halyards at different working loads. Lines are of same diameter; different strengths are compared.

1000

0 0

2

4

6

8

10

12

Stretch (%)

For example: The average load from the wind in the sail on the halyard is 700 kg. An 8mm halyard made of PES rope will elongate almost 1 meter (6% over 15 meters). The same line made with a core made with Dyneema® will elongate less than 10 cm (0.5% on 15 meters). This elongation can be overcome by adjusting the trim.

However, when a gust of wind hits the sail and increases the load on the halyard with 350 kg, the PES halyard

will elongate another 50 cm, compared to 5 cm for the halyard with a core made with Dyneema®. In case of the PES halyard, this dynamic load will distort the sail shape and consequently the sail fails to catch all of the wind.

In addition to losing the optimal sail shape, the rope will also absorb energy when the gust of wind hits the sail.

This energy is lost and therefore cannot be converted into horsepower for the boat. A rope with a core made with Dyneema® absorbs only 10% of the energy absorbed by a full PES rope. In short, every wind shift will be available for increasing speed.

3. Creep Creep is the elongation of a rope under constant high load for an extended period of time. If creep occurs - beyond setting and stretch explained above - the rope will not resume its initial length. Creep is irreversible elongation.

In typical use, creep should not be an issue for performance cruisers. When simulating the creep performance of ropes for a forty-foot performance cruiser, loading a halyard made with Dyneema® with 20% of the maximum breaking load for a period of 8 hours, the elongation of the rope <attributable to creep> will be negligible. When considering the same conditions for a period of one month, the rope elongates only 0.5 percent.

During offshore regattas, such as the Volvo Ocean Race or the Vendée Globe, creep of Dyneema® SK75 may be visible to the vastly experienced crews. However, a new product, Dyneema® SK78, was specially developed by DSM Dyneema for the extreme conditions seen in these races. This innovative fiber was first used in the 2005/2006 Volvo Ocean race by the ABN AMRO ONE and the Pirates of the Caribbean, which finished first and second, respectively.

Dyneema® SK78 fibers enhance stability under long-sustained static loads. This significantly improves both performance and durability. The differences in elongation attributable to creep between Dyneema® SK75 and Dyneema® SK78 are only evident over the extreme period of 90 days in the most recent Volvo Ocean Race.

The halyards made with Dyneema® SK78, under an average load of 2.5 tonnes, would elongate by just 1.3 percent; this is a third of the elongation from halyards made with Dyneema® SK75.

Why superior handling?

Working onboard a racing yacht equipped with lines made with Dyneema® is efficient and less physical demanding. Due to the superior strength-to-weight ratio, lines made with Dyneema® can have a lower diameter; making them easier to handle.

20000 18000

Dyneema® no cover

16000

PBO core

14000

Steel wire

strength

12000

Dyneema® core 10000

LCP core

Fig.3: The diagram shows the strength versus diameter ratio of different yachting lines.

NOTE: In a core/cover construction, the cover does not contribute to the maximum breaking load of the final rope, except in the case of PES, where the cover contributes up to 40% of the maximum breaking load.

8000

Aramid core

6000

PES core

4000 2000 0 6

7

8

9

10

11

diameter (mm)

12

13

14

15

16

Given a breaking strength of the rigging of 5000 kg, the choice this time will be between a 16mm line made with PES and a 10mm line made with Dyneema®. As Dyneema® will not retain water and because of its density of 0,97 g/cm3, lines made with Dyneema® will float. All this, in addition to the fact that lines made with Dyneema® are easier to splice compared to lines made of other materials, results in superior handling for the crew.

Why durable?

A crew relies on the performance and durability of the lines at all times. The worst thing that can happen is a failing rig at a decisive moment during a race. Durability of a rope depends in essence on two factors: • The extent to which the protective cover can withstand abrasion in the jammers and on the rough surface of winch drums.

• How much the fibers used in the core can withstand environmental influences and can hold up to the turning pressure on small diameter rollers/blocks.

Due to the limited heat resistance of the Dyneema® fiber, it is primarily used in the core. Running rigging with a core made with Dyneema® can withstand the harshest, most demanding conditions, due to a combination of properties of the fiber.

Dyneema® does not absorb water, repels dirt, and is very resistant to humidity and UV radiation. These properties are essential for rigging exposed to the harsh conditions, including sun and salt, of ocean racing.

When using a standardized accelerated aging test on different fibers used in modern running rigging, Dyneema® outperforms the other fibers. During a test the fibers are exposed to severe conditions, such as UV and IR radiation, as well as high temperature and humidity. After 336 hours, Dyneema® retains 75% of the initial tenacity, versus 55% of PES, 51% of Aramid 13% of PBO and 10% of LCP fibers.

Since environmental conditions only have a limited impact on the strength of Dyneema®, a halyard with a Dyneema® core can be partially stripped without risking breakage. Thanks to the fibers’ excellent abrasion resistance, the lifetime of the stripped halyard is not jeopardized by chafing against the sail or mast.

If ropes are drawn under load around a narrow radius, such as the sheaves in a block, the outer fibers are stretched while those near the roller are compressed and may break. As seen in Table 1 below, a rope with a core with Dyneema® demonstrates the highest resistance to bending fatigue, whether at a load of 20 percent of maximum breaking load or 1000 kg.

Type of core fiber

Dyneema®

PES

Aramid

PBO

LCP

Nr. cycles to break at 20% MBL

535

479

122

140

353

Nr. cycles to break at 1000 Kg

535

6

38

489

53

Table 1: Bending fatigue performance of different 10mm ropes.

Excellent bending fatigue, abrasion and aging resistance enable ropes made with Dyneema® to perform time and time again.

What do sailors get from rigging with Dyneema®?

• • • •

Maximum breaking strength and lightweight. Enhanced sailing performance through high load level bearing and weight reduction on board.

Ultimate control. The low stretch results in more control while sailing and less energy absorption. Every gust of wind is converted into more speed.

Superior handling. The lines run smoothly through the blocks and sheaves while resisting kinking and hockling. They have a soft hand and are easy to splice.

Reliability. The lines are durable due to high resistance to abrasion, bending fatigue, and environmental influences. In short, they are built to perform time and time again.

For these reasons yachting lines made with Dyneema® are the first choice for demanding sailors all over the world. Ongoing collaboration with the most experienced and demanding sailing teams in renowned races such as the America’s Cup and Vendée Globe will lead to more innovations in running rigging in the future, which will enable faster and more reliable sailing.

The facts reported in this brochure are only few of the important data for running rigging.

For more info on Dyneema® in running rigging and sails, please contact us at: DSM Dyneema B.V. Mauritslaan 49, Urmond P.O. Box 1163, 6160 BD Geleen The Netherlands Tel. +31 (0)46 476 79 99 www.dyneema.com www.extremeriggingperformance.com

DSM Dyneema LLC 1101 Highway 27 South Stanley, NC 28164 USA Tel: (800) 883 74 04 Dyneema® and Dyneema®, the world’s strongest fiber™ are trademark(s) (applications) owned by Royal DSM N.V.

Disclaimer All information supplied by or on behalf of DSM Dyneema LLC and/or DSM Dyneema B.V. ("DSM Dyneema") in relation to its products, whether in the nature of data, recommendations or otherwise, is supported by research and believed reliable, but DSM Dyneema assumes no liability whatsoever in respect of application, processing or use made of the aforementioned information or products, or any consequence thereof. Buyers should perform their testing and analysis to determine the suitability of Dyneema® fibers for their specific applications. The buyer undertakes all liability of the respect of the application, processing or use of the aforementioned information or product, whose quality and other properties he shall verify, or any consequence thereof. No liability whatsoever shall attach to DSM Dyneema for any infringement of the rights owned or controlled by a third party in intellectual, industrial or other property by reason of the application, processing or use of the aforementioned information or products by the buyer.