Syntheic Headstay

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TonyB
Posts: 93
Joined: Tue Sep 25, 2018 2:33 pm
Location: San Francisco Bay Area, California

Syntheic Headstay

Post by TonyB »

Has anyone replaced their headstay on a sloop with a synthetic? I am going to have to replace mine soon and will be moving from roller furling to a camber spar set up. I have been reading a lot of material on various synthetics and maybe now is the time to go that way. Wondering if someone has already done it and any thoughts about the particular wear from the camber spar?
Seems like the synthetic would be better suited to the "cycling" of the flexible mast.
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

walterg
Posts: 41
Joined: Tue Aug 30, 2016 6:48 am
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Re: Syntheic Headstay

Post by walterg »

Hi Tony, the previous owner of my Mull 28 replaced the jib forestay with Vectran in 2012. Last week I was in a local yard for an unrelated issue and the professional rigger there offered me the unsolicitated (but very welcomed) advice that the reason my forestay looks so frayed is that the synthetics like Vectran and Dyneema have low UV resistance and you should only count on them for 3 years or so. If you have access to Professional Boatbuilder magazine, there is a really super article in this month's issue about fabricating your own synthetic standing rigging.
Walter Gotham
Salem MA USA
'87 Freedom 28-Mull #33 "Nova Vita"

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iansan5653
Posts: 28
Joined: Sun May 09, 2021 4:39 pm

Re: Syntheic Headstay

Post by iansan5653 »

US Sailing published this great article on synthetic lifelines that has some relevant info for any synthetic rigging - https://drive.google.com/file/d/14ghdU0 ... sp=sharing. They go into detail on the properties of HMPE, how to size / properly splice it, and how it stands up to chafing and UV.

It looks like they lose a significant amount of strength in an initial 'burn-in' period over the first two years, then much more slowly degrade after that, so I don't think it would be difficult to size the stay to compensate for UV. You're probably looking at replacing it every 5 years at the most, which really isn't bad considering the cost compared to steel. Double braid may help but not solve the problem.
Ian Sanders
1983 Freedom 21 - Shoal Draft
St Petersburg (Tampa Bay), FL

TonyB
Posts: 93
Joined: Tue Sep 25, 2018 2:33 pm
Location: San Francisco Bay Area, California

Re: Syntheic Headstay

Post by TonyB »

Yeah I have been reading plenty on it. UV and Chafe are concerns, but the reality is there is a lot more myth out there than reality. Or rather all synthetics are often lumped together and people don't take the time to understand the differences. Dyneema is very resistant to UV. And pretty resistant to "reasonable" chafe. I wouldn't use it where it will run over sharp edges, but if you plan accordingly, chafe shouldn't be a signifcant issue. And it doesn't corrode from salt water, or impacted by flex cycling on our very flexible masts. Standing rigging applications, even in the tropics are seeing lifecycles long beyond what people originally thought was possible.

Most soft shackles are made with dyneema and are exposed to UV and chafe. But they hold up well.

Important issues are various types of elongation or stretch. While dyneema has very low "stretch" there can be significant mechanical stretching of splices, the weave of the braid, and creep, which is the molecular shifting of dyneema. It is important to heat set it, and pre stretch to try and take as much of all those elongations out as possible. Apparently sizing to reduce creep is basically the most important thing. Once that is determined all the other variables are already well accounted for.

Thinking I may try a heat set/stretched dyneema and see how it holds up. It is relatively inexpensive and I can make the splices myself. I will try and choose an appropriate hank-on system to reduce chafe. I will document what I do and report back! Might be a while.

The upside of doing this on a Freedom is it isn't catastrophic if it fails.
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

TonyB
Posts: 93
Joined: Tue Sep 25, 2018 2:33 pm
Location: San Francisco Bay Area, California

Re: Syntheic Headstay

Post by TonyB »

Anybody know the standard diameter wire used for the forestay on on the F40/40? For use with a camberspar set up?

Thanks!
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

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