The world of ropes is much more full o variations than we might think.
When we enter in the territory of racing ropes, things get even more complicated.
The ropes for a sailboat seem at first glance all the same except for the colour. Nothing could be that far from reality. Some ropes have truly remarkable technical properties. Others are not quite as noble and we need to understand the differences.
Ropes, with some exceptions, are all made up of a core and a cover. The basic lines for cruising boats are often made with a polyester core and cover. Racing ropes mostly have a Dyneema ® or UHMwPE or HMPE core – which is to say the same thing. The cover, on the other hand, is usually a mix of two or more fibres where polyester is used to create the range of colours. The “noble” fibres used in racing lines usually have a limited range of colours.
Racing ropes: the world of noble fibres
Noble fibres distinguish themselves from common polyester for characteristics such as resistance, stretch and melting temperature. In fact, a polyester lines can be cut with a hot knife and finished with a lighter. For many of the high performance fibres this would not be possible. The melting point of Vectran™ is 350°C, that of Nomex® is 350°C – they are not even yet aramids. For aramids such as Technora®, Kevlar®, Twaron® we reach 500°C for Zylon® (PBO) at 650°C.
Among the high performance fibres everyone knows Dyneema®, this is just a registered trademark of the DSM company. Saying Dyneema is like saying Sellotape (a brand) instead of sticky tape. Dyneema is in fact composed of fibers of UHMwPE (ultra-high molecular weight polyethylene) or HMPE produced by Dupont. UHMwPE is 15 times stronger than steel and 40% stronger than many aramids of the same weight. This makes it an extraordinary fibre for making racing ropes.
HMPE also has extraordinary properties in terms of resistance to abrasion and chemicals. However, its melting point is just 150 ° C, even lower than polyester which melts at 260° C. For this reason, most racing lines have a Dyneema core (UHMwPE / HMPE) and a mixed fibres cover. This is to remedy the fact that in many applications, such as spinnaker sheets, a low melting point would be a problem.