Full disclosure, I work for a rope company. But a few things so say regards to Dyneema. First of all Dyneema is a brand name that comes in a wide range of “models”. The actual material is UHMWPE or Ultra High Molecular Weight Polyethylene. A Dutch company DSM makes the yarns with subtle differences in order to achieve different characteristics such as strength and elongation and something called “creep”. The grades of Dyneema are categorized by an SK number with the higher numbers yielding higher performance, generally speaking. However DSM is not the only company that makes UHMWPE yarns. Honeywell makes an equivalent yarn called Spectra which also comes in different grades. Finally there are generic offerings, typically Asian made that are often much cheaper than Spectra or Dyneema but quality tends to vary. A rope maker can choose which yarns to use in a particular rope, using the fibers to make either a 12 strand hollow braid or to use the high modulus fibers as the core in a low stretch double braid with an outer cover braid of a high wear or YV stable material like polyester. Doing the latter adds weight, but dramatically increases longevity. Even if UHMWPE is used just for the core, most companies will still coat the yarns in a urethane bath to provide additional protection from chafe and to provide color coding. Finally, some rope makers will use a process called heat setting the Dyneema rope by pre-stretching and aligning the fibers and then exposing the rope to a heat process that removes most of the creep (non recoverable elongation on a molecular level). There’s usually a slight reduction in overall strength with heat set ropes, but far less stretch. It is these heat set ropes that I would recommend for any standing rigging application. UHMWPE is quite slippery and achieving proper tension and maintaining it under load can be challenging without the proper terminations and fittings. Several companies like Colligio and Blue Wave offer specific hardware to create standing rigging solutions that provide adjustments and tensioning solutions. Hope this helps.. Chuck Gilchrest S/V Half Magic LF 35
Sent from my iPhone > On Jul 23, 2021, at 9:02 PM, Dave S via CnC-List <cnc-list@cnc-list.com> > wrote: > > Josh - can you point to any good resources on its use for lifelines? > > Thanks, Dave > 33-2 Windstar > > Sent from my iPhone > >>> On Jul 23, 2021, at 8:59 PM, Josh Muckley via CnC-List >>> <cnc-list@cnc-list.com> wrote: >>> >> >> I'm a huge fan of dyneema. It is relatively cheap and easy to finish >> yourself with few if any special tools. I currently have lifelines, topping >> lift, various soft shackles and continuous loops made of dyneema. No >> problems. I might reconsider using it for standing rigging but everything >> else I'd advocate for unequivocally. >> >> Josh Muckley >> S/V Sea Hawk >> 1989 C&C 37+ >> Solomons, MD >> >>> On Fri, Jul 23, 2021, 20:45 Hoyt, Mike via CnC-List <cnc-list@cnc-list.com> >>> wrote: >>> Do you actually use these? Our frers 33 has check stays and although they >>> help with main shape we rarely use them due to added complications tacking >>> etc >>> >>> Mike >>> Peraiatence >>> Halifax >>> From: cenelson via CnC-List <cnc-list@cnc-list.com> >>> Sent: July 23, 2021 9:26:54 PM >>> To: Stus-List >>> Cc: cenelson >>> Subject: Stus-List Wire vs. Dyneema check stays >>> >>> >>> I have decided to replace my standing rigging on Water Phantom, my now 26 >>> yr old 1995 C&C XL/kcb. >>> >>> The rigger has recommended staying with a rod replacement vs. wire to >>> better match the rod fittings, esp. at the mast head and to save money. >>> >>> He also recommends going with dyneema, instead of wire, for the check >>> stays. >>> >>> My concern is uv damage to the dyneema which I understand has been a >>> problem with using it vs. wire. >>> >>> His response is that the early coatings used to protect dyneema led to >>> short lifetimes but that the newer coatings have solved that problem. >>> >>> OTOH, my wire check stays are still fine “…after all these years…” >>> >>> My question is should I go with dyneema for the checks or stay with new >>> wire assuming the costs are similar? >>> >>> Thanks, >>> >>> Charlie Nelson >>> >>> >>> Sent from the all new AOL app for iOS >>> Thanks to all of the subscribers that contributed to the list to help with >>> the costs involved. If you want to show your support to the list - use >>> PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - >>> Stu >> Thanks to all of the subscribers that contributed to the list to help with >> the costs involved. If you want to show your support to the list - use >> PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - >> Stu > Thanks to all of the subscribers that contributed to the list to help with > the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
