A few comparatively thick fibers (Ø 0.3 mm) are fed in parallel to the braiding process.
Many very thin fibers (0.001 mm) are used as a bundle during the braiding process. This is the most widely used type of construction in yachting ropes.
The fibers are not arranged in parallel in the bundle but exhibit a more or less random type of arrangement. This is why the fiber bundle has a comparatively rough surface.
Polyethylene = Dyneema®
DSM, the Dutch chemical corporation, changes polyethylene on a molecular basis and also turns the fibers in one direction. The result is Dyneema®, a material that exhibits increased breaking loads (very low elongation at break for synthetic fibers) and reduced stretch. Furthermore, Dyneema® has a very low specific weight that imparts buoyancy, good abrasion strength, and resistance to sunlight to the fiber. The only downside of Dyneema® is that it creeps. This means that the fiber will show permanent elongation under load. However, due to its impressive advantages, Dyneema® is the most widely used high-tech fiber in the yachting rope segment and particularly well suited for use as a core material for high-tech cordage. The core bears the load, while the cover merely serves as a protection against abrasion and light. Therefore, it is possible to remove the cover from the rope ends without reducing the rope's breaking strength. This is why Dyneema® can be used for all high quality products such as sheets, halyards, and trim lines.
Liquid crystal polymer (LCP) = Vectran®
Hoechst Celanese, the U.S.-based corporation, produces liquid crystal polymers (LCPs) under the Vectran® brand, which are highly complex, modified polyester chains. This product stands for minimal stretch and highest breaking loads, high temperature resistance, and low sensitivity to bending and sharp edges. What is more, unlike Dyneema® it does not creep. However, its big shortcomings are its low UV resistance and the high price of its raw materials. Therefore, it is indispensable to surround a Vectran® core with a protective cover in order to counteract its UV instability. For this reason, this zero-compromises high-tech fiber is mainly used in regatta racing.
Polybenzoxazole crystal polymer (PBO)
The Japan-based Toyobo corporation produces polybenzoxazole crystal polymer under the name PBO. PBO is a high-tech fiber that combines highest breaking loads with minimal stretch and high temperature resistance. Its only weakness, however, is its extremely low resistance to sunlight.
Aramid = Kevlar®, Twaron® or Technora®
Japan-based Teijin produces Twaron® and Technora® fibers, while U.S.-based DuPont produces Kevlar®. Each of these products is a para-aramid fiber made of co-polymers. In the yachting cordage segment, this fiber is highly appreciated mainly because it exhibits zero stretch, highest breaking loads, and extremely high temperature resistance. This makes it ideal for use as a cover fiber for winches. However, using it on stoppers is not recommendable, as this fiber has only low resistance to bending across sharp edges. Another downside is its sensitivity to sunlight.
Polyester (PET or PES)
Polyester offers a great number of chemical and physical advantages. It boasts relatively good breaking loads and low stretch as well as salt water resistance, good abrasion resistance in both dry and wet conditions, and good resistance to sunlight. In view of this large number of benefits, PES is used frequently for the production of yachting cordage. In the cruising segment, it is employed as material for both cores and covers of halyards, sheets, and mooring lines. Due to the high density of this material and its sinkability, it can even be used as an anchor line. In high-tech applications, it is often used as a cover material in order to afford UV protection to cores made of more sensitive materials.
Apart from a high breaking load and stretch, polyamide has a special property, namely, its abrasion resistance which is better in wet than in dry conditions, as this fiber is able to absorb up to 7% water. For this reason, ropes made of PA are often used as mooring or anchor lines. However, when kept in contact with moisture for too long, the material can become stiff. Another downside as compared to polyester is its relatively lower UV resistance. For this reason, polyamide is increasingly replaced by polyester.
Polypropylene (PP) = XLF
PP is extremely lightweight and even buoyant and it exhibits sufficient abrasion resistance and temperature resistance. PP is used for simple applications in the yachting rope segment. Its relatively high stretchability makes polypropylene a popular material for allround ropes, towing lines, and simple mooring lines. However, it is rarely to be found in high-tech ropes.