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Best rope for main halyard |
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Topic: Best rope for main halyard Posted: 19 Mar 09 at 3:41pm |
James, what is mast foot pressure a la windsurfers? Paul, sorry to say Chewy and me are one and the same - I lost my login details! Tempted to do the Thornbury regatta though. Edited by Peaky |
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craiggo
Really should get out more Joined: 01 Apr 04 Location: United Kingdom Online Status: Offline Posts: 1810 |
Post Options Quote Reply Posted: 19 Mar 09 at 10:40pm |
Aaahhh it all becomes clear now. The mysterious Peaky is in fact Chewy!
Jimbo when I was in the 600 fleet the main reason for going to 2:1 other than peer pressure was a belief that you could use the mechanical advantage to ensure that you had enough tension in the halyard to hold the head of the main at the top of the mast even with yehaaa cunningham applied. In my opinion it didnt work, as you regularly saw mainsail heads 6" below the mast tip even with 2:1. I firmly believe that this is down to the loss of mechanical advantage as you go block to block at the top. Once creep and stetch set in you actually end up with more rope to stretch and creep thanks to the 2:1 and so the sail appears to drop lower. Best way to rig the 600 was always to make a crude 3:1 purchase with the tail at the bottom of the mast and pull on a load of tension. Even with extreme cunningham you get only a small drop in mainsail. Edited by craiggo |
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Paramedic
Really should get out more Joined: 27 Jan 06 Location: United Kingdom Online Status: Offline Posts: 929 |
Post Options Quote Reply Posted: 20 Mar 09 at 7:25am |
A well known mast maker tested this out with weights. The results were astonishing in that the halyard running inside the mast operated under a mechanical disadvantage from kicker, cunningham and mainsheet loads so the the rope in the mast actually holds twice the load of the luff on the sail. If you think about how you rig up a cunningham this does make sense. In some classes you want this to help de power, but in merlins with the flexible carbon spars the "bow and arrow" effect should cause a power drop just when you want it least, ie force 2 or 3. Halyard locks are becoming popular again, but I opted for a 2:1 halyard but haven't really sailed enough since to draw any conclusions. It looks good on paper though. Edited by Paramedic |
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BBSCFaithfull
Really should get out more Joined: 06 Dec 05 Location: United Kingdom Online Status: Offline Posts: 1251 |
Post Options Quote Reply Posted: 20 Mar 09 at 9:27pm |
I have a release mechanism in my mast so no worried rib drivers
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Medway Maniac
Really should get out more Joined: 13 May 05 Location: United Kingdom Online Status: Offline Posts: 2788 |
Post Options Quote Reply Posted: 20 Mar 09 at 11:05pm |
Sounds interesting. How does that work? |
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BBSCFaithfull
Really should get out more Joined: 06 Dec 05 Location: United Kingdom Online Status: Offline Posts: 1251 |
Post Options Quote Reply Posted: 21 Mar 09 at 4:35pm |
It comes from cst. Its basically a pin attached to a rope on the bottom of it.
Through which the head of the sail is attached http://www.cstcomposites.com/images/Dinghy%20Mast%20head%20Q .Release.JPG Alex |
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JimC
Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6649 |
Post Options Quote Reply Posted: 21 Mar 09 at 5:43pm |
If I were on the safety boat I'd be delighted to see it. No wire halyards, no expensive ropes, just 5p worth of string I can unhook or cut with a knife and the sail comes down immediately with no snagging of rope in the cockpit. Edited by JimC |
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