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S/V Wyndwitch - Morgan 24
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Discussion Starter #1
I have a Morgan 24/25 with a furler and will be rigging a Solent stay per classic form from close to masthead to about a 18"(max) behind the furler/headstay. I'm attracted by the use of synthetics for the stay but concerned about dimensions because if possible would prefer to stay with the hanks etc on current storm jib which is virtually new (unused)....

anyone know reasonable guidelines for equivalence with steel in synthetic lines? Any experience would be interesting to hear on this....
Thanks:confused::laugher:cool::cool:
 

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The problems with using synthetics for stays haves been UV degradation and chafe. If you use hanks for your Solent jib, you will have chafe. If you keep an eye on it, that may be acceptable, though the chafe may be heavier near the top, where it will be harder to see. You will be getting chafe from the regular jib against it if you leave the Solent stay rigged, and chafe against the mast and/or shrouds and leech of the jib if you lead the stay aft when it's not in use. There are too many variables to say how much chafe you might get or how long before a synthetic stay might chafe through. UV degradation is harder to see, but a heavier diameter line (3/8"??)should probably serve 5 or so years before showing anything, and might last much longer than that. (The forestay is still there if the Solent stay fails, so the mast isn't going to drop anyway.) SS wire will not chafe as much, and might be expected to hold up for 20+ years. A wire Solent stay will definitely chafe the genoa if you leave it rigged, so it will definitely need to be tied off further aft when not in use. How much sailing do you do on Long Island Sound in conditions that would call for a Solent? On a boat I sailed that had one, we only hoisted it when the wind got up over 20 knots.
 

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Oyster,

Dyneema is not suitable for standing rigging, it will creep like crazy. There is an annealed for of dyneema called Dynex Dux that is used for standing rigging, and is fine for yanked on sails, so long as the hanks are burr free.

Unlike wire which is sized for strength Dux is sized to control creep, to do this you need to know the pre tension carried on the stay, or make a rough guess. Note that this is the tension when sitting at the dock, not the loaded tension while sailing.

As a rough idea you need to have no more than 5% of the MBL as the pretension. It seems excessive, but this keeps creep down to ~.1% a year which is controllable.

UV has not been shown to be of particular concern to Dux unlike some of the other synthetic lines (PBO for instance). Right not the recommendation is a service life of about 8 years in the Carribean, possibly more in lower UV areas. But it hasn't been in service long enough for good data to exist past this point. I know boats that are pushing past the 8year mark and their line looks just fine.

And btw wire has an expected lifespan of 8 years too.
 

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S/V Wyndwitch - Morgan 24
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Discussion Starter #4
Thank you both for your helpful replies. I just picked up on the
Dynex dux and its special qualities. But looks like wire is the way for me on this with a 4 to 1 tackle to tension the stay when in place. Re the first question I am on south shore and when I do go offshore need to be prepared for whatever comes along if heading to Block or Ct which I'd like to do next season. I am experimenting with different ways to balance the boat on a variety of conditions 30 kts is not unusual here fall winter and spring.
 

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A New Adventurer
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I've often wondered if dyneema creep was a big deal with a solent stay. This is an application where the stay is only rigged/tensioned for a short period of time, and typically with a mechanical fastener with a good bit of travel.

If using the appropriate size of Amsteel Blue and rigging only when used for a storm jib, how fast will creep kick in? Day, week, month?
 

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I've often wondered if dyneema creep was a big deal with a solent stay. This is an application where the stay is only rigged/tensioned for a short period of time, and typically with a mechanical fastener with a good bit of travel.

If using the appropriate size of Amsteel Blue and rigging only when used for a storm jib, how fast will creep kick in? Day, week, month?

Creep by definition requires high sustained loads over long periods of time to be meaningful. I am making up numbers here, but they are based on prior experience, so probably close....

If a Dux stay is sized properly it will creep about .1 inch a year assuming 5% of the MBL as static tension. If you decrease the amount of time it is loaded to just a few hours a year, well 365*24=8,760hours in a year. So for every hour the Dux is loaded it will creep 1/87,600 of an inch.

For static loads there is also the reality that as the line stretches the tension on the line goes down very quickly, so unless it is constantly being re tensioned the creep rate will start going down exponentially as the load is decreased.


I know some of the open 60's are using Dux standing rigging, and they carry something like 20,000psi of tension in their rigs. They actually use hydrolic rams to jack the mast up while underway. And the Open's haven't had an issue.
 

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S/V Wyndwitch - Morgan 24
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Discussion Starter #8
Thanks Greg,
Those figures suggest that for this purpose the creep would not be a significant issue..but Im going with wire largely because I wish to retain the old hanks on the storm jib and abything else I hang on there.
 
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