Syntheic Headstay

TonyB
Posts: 100
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
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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"

iansan5653
Posts: 41
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
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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
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Joined: Tue Sep 25, 2018 2:33 pm
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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

TonyB
Posts: 100
Joined: Tue Sep 25, 2018 2:33 pm
Location: San Francisco Bay Area, California

Re: Syntheic Headstay

Post by TonyB »

Ok folks I have gone and done it. Guess I will be the guinea pig!
I did a lot of research on this topic and talked with quite a few folks including riggers and a sailmaker. Here is what I came up with.

1) Synthetic rigging really makes sense. The price has come way down, and while it is more vulnerable to chafe and UV than wire, it is less vulnerable to salt water. Installed synthetic rigging is lasting as long as 15 years. It significantly reduces weight aloft and has a number of safety factors over wire. And the splicing is pretty easy so you can do the work yourself.

2) Best practice is to size the rigging for creep, not strength. But creep only happens when the rig is under significant tension for long period of time. Our rigs have very little tension. So I sized for strength. I replaced the 3/8 inch stainless (breaking strength 12,000 lbs) with 6mm heat set, prestretched dyneema (breaking strength 12,385lbs) . Replacing 12 pounds of steel with about a half pound of dyneema.

3) Best practice is to use 8:1 thimbles at both ends. But they are expensive and I was impatient and didn’t want to wait for shipment or spend the money. So I used Ronstan thimbles which are super smooth and form a compete “ring”. We will see how it works out.

4) Lastly, best practice is to use “soft hanks”. But people complain that they make dropping sails more difficult. And after reading how durable this dyneema is, and knowing that soft shackles are used on metal fittings all the time and rock climbers use carabiners on it, I reached out to Colligo Marine who specializes in synthetic rigging. They said no problem to use bronze hank ons. That they have customers that do it all the time. It will chafe faster but it will still take many years.

So I am the guinea pig for our group. We will see how it goes. Obviously with our rigs, breaking a forestay is less catastrophic than for most boats. I have some photos I will post later.
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

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newt2u
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Re: Syntheic Headstay

Post by newt2u »

Tony, I would be interested to see some pictures, especially of the ends.
Rockin - F21 twin drop keels - located Milford Haven
Wintered in Shropshire where I am when I’m not sailing

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

Re: Syntheic Headstay

Post by TonyB »

Trying to figure out how to post images from my iPhone!
Tony
SV Circe 1997 Freedom 40/40 - Hull #20 - Brickyard Cove Marina, Richmond, CA

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newt2u
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Re: Syntheic Headstay

Post by newt2u »

Click on attachments and when you click on add files it will ask you to take a photo or browse your photos. Just select a photo and add.
Rockin - F21 twin drop keels - located Milford Haven
Wintered in Shropshire where I am when I’m not sailing

TonyB
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Joined: Tue Sep 25, 2018 2:33 pm
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Re: Syntheic Headstay

Post by TonyB »

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

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