Rope materials

Sailing ropes are produced of many different materials: synthetic fibres. Don't be afraid of all chemical terms. It is worthwile to have some knowledge of the most commonly used fibres and their characteristics. Dyneema^®, polyester, aramid fibres, etc. are explained on this page and their typical applications on board of sailing boats.

Sailing rope materials compared

Material	Brandnames	Elongation 50% Breaking strength	Breaking Strength (ø 8mm [kg])	Density [kg/dm3]	Melting Point [°C]	UV resistance (1=low; 5 high)	Abrasion Restance	Typical Applications
Polypropylene		16%	1350	0.91 (float)	170	2	Poor	Mooring line
HMPE - High Molecular Weight Polyethylene)	Dyneema®, Spectra, Stirotex	3.4%	6300	0.97 (float)	150	5	Good	Halyards/ Sheets/ Trimlines (regatta)
Polybenzobisoxazole (PBO)	Zylon	1.8%	8000	1.58	650*	1	Poor	Rigging (Regatta)
Liquid Crystal Polymer	Vectran	2.2%	6000	1.4	330	2	Very Good	Halyards/ Rigging
Polyester	Dacron	8%	1800	1.38	260	5	Very Good	Halyards/ Sheets/ Trimlines (cruising)
Polyamide	Nylon	16% dry, 20% wet	1900	1.14	220-250	4	Good	Mooring/ Anchor line

Remark: Table is for comparison purpose, differences occur within each material (depending on grades/ treatments)

Aramid: Technora

Aramid fibres are often sold under the brand names Kevlar and Technora. Premiumropes sells ropes with Technora in the cover. Technora main advantage is its resistance to high temperatures. This makes covers with Technora excellent for situations where the friction on a winch can become so great that a polyester cover will melt.

HMPE: Dyneema^® and Spectra^®

In recent years lines with HMPE (also known as UHMWPE)  fibres have become popular very fast. HMPE fibres are usually known with their trade names, such as Dyneema^® and Spectra^®. Premiumropes sells ropes made with Dyneema^® fibres. It’s popularity amongst sailors is not surprising, since it has very little stretch and is also twice as strong as polyester. Moreover, it is so light that it floats on water. Dyneema^® fibres have a good chemical resistance. Mechanical properties are unaffected by seawater, oil or other common chemicals. Also, the material is very durable.

Dyneema® fibers are smooth (self-lubricating) and have a low melting point. A good cover jacket is sometimes needed for additional protection. For example, for racing yachts a cover of Technora is recommended to protect the core from heat from friction on winches. Dyneema^® fibres are UV resistant. Where the line does not wear or is held by hand, it’s fine to remove the cover in order to spare weight (tapering). This works well for example for spinnaker sheets. 

Splicing ropes with Dyneema^® fibres is quite easy. A line with Dyneema® fibres gets 95% of its strength out of the core, the cover only serves for protection. So for splicing, the cover is not needed. Just make a simple ‘bare eye’. The principle of a Dyneema eye, is a core-to-core splice, in which the length of at least 60 times the diameter of the rope is taken back into itself.

HMPE fibres are often used to replace stainless steel wire. Softshackles, back-stays and loops on board of sailing yachts are good examples. Also for industrial purposes HMPE fibres are gaining ground.

Dyneema^® fibres are available in various grades: SK38, SK78 and SK99. The higher the number, the lower the stretch and stronger the fibre. Sailors will notice the difference in performance between SK38 and SK78 fibres. However the step up to SK99 fibres is reserved mainly for off-shore racing. Stirotex® is another brand of HMPE fibres that is sold by Premiumropes. In the table below, we have specified the various UHMWPE fibres that are used in our ropes. 

Dyneema® SK99	This is the strongest of all Dyneema® fibres and beats SK78 with about 15% to 20% on strength. But that comes with a price. Therefore this grade is merely used for extreme situations where ultimate strength is of the essence.	DX Core 99, Powerline SK99. Upon request we can produce DX Cup with a core of Dyneema® SK99 fibres
Dyneema® SK78	SK78 is the most popular grade of Dyneema® and the best choice for regatta sailors. It is 25% stronger than SK38.	DX Cup, DX Cup Grip, DX Core 78, DX Cover, DX 78 HPS
Stirotex®	An economic choice of UHMWPE fibres with excellent strength and low stretch. Performance sailors will not be disappointed with the quality of ropes made of Stirotex®.	S Cup, S Core
Dyneema® SK38	This fibre has a lower tenacity than the other super fibres. However, compared to polyester SK38 wins on strength and low stretch characteristics. Critical recreational sailors will notice a big difference in performance when stepping up from polyester ropes.	DX Performance

PBO: Zylon

PBO (Polybenzobisoxazole) has the lowest elongation of all lines, has a very high breaking strength and very little creep (elongation under continuous high load). Moreover, it has a very high melting point. The main disadvantage of PBO is the UV sensitivity. A PBO fibre without cover, 24 hours exposed to UV light, loses all 50% of its breaking strength. PBO should therefore always use a cover. PBO is often used as a backstay in regattas. PBO rigging must be replaced after 3-5 years.

Polyamide: Nylon and Cordura

Polyamide is sold under various trade names such as Nylon and Cordura. It is a flexible line that sinks. Nylon is strong, has quite some stretch and is good UV resistant. Premiumropes sells ropes with Cordura in the cover. This fibre gives better grip to ropes. Ropes with Cordura fibres in the cover are made for sheets and control lines that are held by hands, typically in dinghies.

Polyester

A polyester line is relatively inexpensive and usually provides enough functionality to the cruising sailor. The main disadvantage is that is has some stretch. Less than a nylon line, but more than modern fibres such as Dyneema^®. For racers polyester has too much stretch. Pre-stretched lines are often sold. Polyester lines do not float.

Polyester ropes can either be:
• Twisted: consists of a number of twisted strands. Twisted ropes are mainly used as mooring and anchor lines and on traditional ships.

• Braided: this can be either a single braid or with cover: a double braid rope. A braided line is less susceptible to damage, become less tangled and stretches less than a beaten line. It is also more comfortable in the hand.

For mooring lines Premiumropes advises double braid or eight-strand polyester ropes

Splicing polyester: a braided polyester line gets about 30% of the breaking strength of the cover. Hence, double braid polyester, the core must be spliced into the cover. This is a different technique than with core dependent ropes, e.g. made of Dyneema^® fibres.

Polypropylene

Polypropylene (also polypropene or PP) is a synthetic fibre with moderate wear resistance and low durability. Polypropylene lines are rough and pleasant to hold. They also stay afloat and can be a good choice for towing a dinghy. Polypropylene is not as strong as polyester, but is much cheaper to produce. The qualities differ. The strength (and price) is reduces when no or poor UV treatment has occurred. Polypropylene is used primarily for mooring. Premiumropes advises to use polyester for mooring lines over polypropylene.

Vectran

Vectran is slightly weaker than Dyneema® fiber, but does not suffer from creep (elongation under continuous high load). At the same diameter, Vectran is five times stronger than steel. The line stretches barely (1.8%) and is very flexible to use. Because of these properties Vectran is suitable as halyard or backstay. As Vectran has poor UV resistance, the line should always have a cover.