New England Ropes alone makes at least a dozen different ropes that contain Dyneema. Some of them are so slippery then don't even work on winches, others are covered with polyester, or have blended fibers, and will work well in friction critical applications.
"Dyneema" is just the brand name for a particular brand of polyethylene fiber. "Spectra," "Vectran," "Technora," "Zylon," and "Kevlar" (among others) are brand names for different chemistries of very high strength, low stretch fibers. Not all of them are as slippery as others, and not all of them are usable, uncovered, in full time exposure to sunlight. Kevlar, for example is not UV stable and must be covered if in the sun. Dyneema and Spectra are UV stable, but in raw form are extremely slippery. To be useful on a winch they must either have a cover, or have other fibers blended into the yarn to increase the coefficient of friction.
Just to make things even more complex, some high tech line sun covers are really JUST sun covers, and will slide along the core if put under load on a winch or in a clutch. This is more of a problem with the polyethylene fibers (Dyneema and Spectra) than the fibers like Kevlar and Vectran.
On the Amel main outhaul line, and on the main traveller control line, the type of construction of the line, and the material the surface is made of are more important to performance than the exact chemistry of the core fiber.
When shopping for a high-tech line always look for one that is specifically recommended by the manufacturer for use in clutches and winches. A hint: the phrase, "abrasion resistant" is marketing-speak for "very slippery."
Some of these high tech fibers also suffer long term damage when making tight turns around the small sheaves used in our systems. Looking for those lines that are recommended for this is also a good idea.
Just looking in New England Rope's listings, "Poly Tec" or "Endura Braid" is a good choice in Dyneema core, and V100 in Vectran. Other manufacturers will have their own names and brands for lines of similar performance.
Norfolk, VA, USA
Following the cold front offshore--and south--tomorrow!
---In amelyachtowners@..., <brouse@...> wrote :
Today, I learned that Dyneema rope is made with a Dyneema braid outer sheath and also with a Dyneema core and a Polyester braid outer sheath. This is probably the reason for the mixed results from owners using Dyneema.
I had the outhaul line very tight 12+ years and never overhauled the outhaul gearbox. I did have a new spare waiting for a failure and maybe that is the reason it never failed...either that, or the famous Danny Simms grease access to the gearbox!😀