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Twin Trapease

Posted: Fri Jul 17, 2009 7:47 pm
by Phil.T
Hi All,
Any one fitted additional trapease wires. My 11 years old has had his first flyer recently and I would like to go out there with him in the right conditions.

Posted: Fri Jul 24, 2009 5:40 pm
by Derek James
Phil ,
my advice is - don't do it ! Not saying anything about your weight but there is only so much pressure you can impose on your mast :lol: If you get my drift :wink: If you have your son on the wire you can concentrate on boat speed and go for the Draycote water speed record !
Cheers
Derek.

Posted: Sun Jul 26, 2009 5:40 am
by Phil.T
Derek,
sarcasm is the lowest form of wit, so I am told, and now everyone thinks I'm fat! :cry:

Posted: Sun Jul 26, 2009 10:37 am
by Bob Carter
Hi
No one to my knowledge has put 2 trapezes on a Sprint 15. It would clearly be out of class but it would also be over the top, in my view. The boat is fairly under canvassed as boats go. We stay out in much stronger wind than most other classes. Sailing up to a force 7 is pretty good 2-up (or 1 1/2 up) with no trapeze or single handed with 2 sails and a trapeze. Sailing 2 up with 1 trapeze only works if the crew is light weight (or wants some fun dangling). I can see no benefit in having 2 trapezes - certainly the righting moment does not require it. As the wind increases the righting moment when beating is not the issue (just let the traveller out a bit and keep the mainsheet tight) but it is the risk of a pitchpole when on a broad reach - 2 wires will not help there as no one will be wiring.
Cheers
Bob

Posted: Sun Jul 26, 2009 6:23 pm
by Andrew Hannah
Hi Bob,

"The righting moment" is a term one hears from time to time. What, exactly, is it?

Andrew.

Posted: Mon Jul 27, 2009 9:24 am
by Bob Carter
Hi Andrew,
The righting moment is the force keeping the boat upright times the distance from the pivot point (the leeward hull on a catamaran). The variable bit of this is (Helm's weight X distance of the helm's centre of gravity from the leeward hull centreline + Crew's weight X distance of the crew's centre of gravity from the leeward hull centreline).
Cheers
Bob

Posted: Sat Aug 22, 2009 8:13 pm
by Phil.T
Hi all
Thanks for your replies. It was never my intention to counter the sail more a case of sharing the experience with my son.
However I was out with a heavy weight friend( Probably 30 stone in all) on Thursday evening in a blow and got thoroughly washed with waves and spray and couldn't see a thing half the time. Good job we were the only boat out, great fun!

Posted: Tue Aug 25, 2009 6:49 pm
by RobBowen
There is also quite an interesting discussion on the 18 website about twin wiring. Although possible, they with their stronger masts seem to think that it is not a great idea... http://pub44.bravenet.com/forum/static/ ... 6&cmd=show
Rob

Shrouds

Posted: Wed Aug 26, 2009 2:07 pm
by Steve Willis
It is not just the mast strength but that of the shrouds and forestay.

When we bought our 18 years ago everyone told us do not go three up with all adults. There had been a number of shroud and mast failures.

The Sprint mast is much lighter construction and I suspect you could end up fracturing the hound plate miunting or the mast in that area. Even more risk on a two piece mast.

Steve

Posted: Fri Aug 28, 2009 6:34 pm
by Charles
Phil

I'd concur with Bob that you are better off sat down with light weight crew trapezing.

My daughter, Elenya, likes to trapeze in any wind, but if it gets a bit hairy you have a chance to catch them if you are anchored to the boat & it decides to nosedive.