Latest developments in rope: Stronger than steel and floats

The latest rope technology from Marlow © Richard Langdon / Team Phaedo

Paul Dyer, Technical manager at Marlow Ropes, takes us through three developments in marine ropes that impact on performance.

Rope technology has seen significant developments over the past three decades years. From revolutionary new fibers of cores and covers that impact on strength to dramatic advances in the levels of rope durability, diameter, stretch and creep.

DIAMETER

In some situations we have developed rope lines that can replace a line almost twice its diameter. The effect of reducing the diameter of rope, while maintaining all the properties of the larger variety, has had untold benefits in the sailing world – providing considerable weight saving. This saving is multiplied when you consider that for any mass removed from the rigging more mass can be removed from the keel.

STRETCH

Technology development has also facilitated low stretch ropes - the ultimate achievement in rope development. This allows sail settings to be maintained under a variety of conditions - but will also place much higher peak loads on deck fittings, so when upgrading the lines of an older boat particular, the deck gear will usually also need to be modernised.

CORE & COVER

New modern fibers have come along way...and still we continue to invest a lot in research, development and ongoing testing. Traditional braid-on-braid ropes have 50 percent core and 50 percent cover, and share the load equally. Higher performance ropes generally have a core that takes the bulk of the load, accounting for up to 95 per cent of the rope's strength, and a protective outer cover that provides abrasion resistance, protection from sunlight and so on.

Some are used without a cover, particularly high-strength control lines, but these will normally have a coating that improves handling characteristics and provides some UV protection.

MATERIALS

Now the latest high tech material is Dyneema. Dyneema is an Ultra High Molecular weight Polyethylene (UHMwPE) or High Modulus Polyethylene (HMPE) fibre. Known as the world's strongest, lightest fiber – 15 times stronger than steel, yet floats on water – Dyneema comes in a number of grades and performance specifications. It is used to stop bullets, repair human joints and improve the longevity of apparel.

As the demands on high performance running rigging are becoming higher, Marlow's Grand Prix Series offers core options using Dyneema, Vectran, and Zylon (PBO). Each has it's own strengths and weaknesses, but Dyneema has become the "Gold Standard" for performance running rigging.

For Marlow, Dyneema is an ingredient material in many of its highest performance ropes as it offers by far the best strength to weight ratio of any material used in rope manufacturing and is the material of choice for high performance cores.

Its enviable properties include:

• High Strength: On a weight for weight basis, Dyneema is 15 times stronger than steel wire


• Light Weight: Size for size, a rope made with Dyneema is 6 times lighter than steel wire rope

• Water resistant: Dyneema is hydrophobic and does not absorb water, meaning it remains light when working in wet conditions

• It Floats: Dyneema has a Specific Gravity of 0.97 which means it floats in water (specific gravity is a mesure of density. Water has an SG of 1, so anything with SG<1 will float and an SG>1 means it will sink)

• Chemical resistance: Dyneema is chemically inert, and performs well in dry, wet, salty and humid conditions, as well as other situations where chemicals are present.

• UV Resistant: Dyneema has very good resistance to photo degradation, maintaining its performance when exposed to UV light

Next up Paul will talk standing rigging and breaking strength figures... what this space Paul Dyer has over 20 years experience in the design, production, testing and use of fiber ropes. He has also worked on customised ropes for any number of fantastic applications, including boats for the America's Cup. For more information and advice contact www.marlowropes.com