wishbone sails

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vanessa
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Joined: Sat Jan 10, 2009 10:22 am

wishbone sails

Post by vanessa »

We have a freedom 35 yacht with 2 unstayed masts and wishbone sails. The two edges of each of the sails have 5 pairs of eyelets which are supposed to be tied together. At the moment they are tied with thin rope across the edges with a reef knot. Someone told us that was incorrect as they may chafe. They should be joined with a toggle system, ie. a short fatter rope with two overhand knots, one on the outside of each eyelet. I am quite happy to make these myself by tying thick rope with overhand knots and sealing with a match to prevent it coming undone. Is there a gismo one could buy that is designed specially for the job or should I carry on with my home made approach ? Very grateful for any suggestions. Thanks.

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Michel
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Location: Zaanstad, the Netherlands, EU

Re: wishbone sails

Post by Michel »

Hi Vanessa,

Welcome to the board. I had an F35 like yours for eight years. The suggestion you got to change the ropes is correct. You should not tie both plies of the sail too tight together; they must be able to slide along each other to ensure the windward and leeside of the sail have the best curve. As you know, the windward side is pushed to leeward aft of the mast and the leeward side is sucked away further to leeward by the low pressure area behind the sail. That is aerodynamically optimal. I had 1' lengths of 1/4" rope through the eyelets with a figure eight knot at each end on the outsides of the sail.

Best,
Last edited by Michel on Sun Jan 11, 2009 6:00 am, edited 1 time in total.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

vanessa
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Joined: Sat Jan 10, 2009 10:22 am

Re: wishbone sails

Post by vanessa »

Michel wrote:Hi Vanessa,

Welcome to the board. I had an F35 like yours for eight years. The suggestion you got to change the ropes is correct. You should not tie both plies of the sail too tight together; they must be able to slide along each other to ensure the windward and leeside of the sail have the best curve. As you know, the windward side is pushed aft of the mast and the leeward side is sucked away by the low pressure area behind the sail. That is aerodynamically optimal. I had 1' lengths of 1/4" rope through the eyelets with a figure eight knot at each end on the outsides of the sail.

Best,
Hi Michel
Thank you so much for your really helpful suggestion with the explanation for why they should slide along. I was thrilled to get this answer as I shall start to make the figure of eight knots probably tomorrow. I've never done one of these forum things before, so it's taken me quite a while to work out how to send a message and also how to reply to yours ! I finally figured it out though !Thanks again.
We sail our Freedom out of Plymouth, Devon, UK
All the best
Happy New Year
Vanessa

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THATBOATGUY
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Location: F40 CC CK Maryland
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Re: wishbone sails

Post by THATBOATGUY »

I sailed into and out of Plymouth a few years ago and had a really nice week long visit there. The weather co-operated and we got do hike a little of the Southern Coastal Trail. Glorious. We will definitely be back.

I got to reading your initial post again and I'm wondering if when you asked about your home made method you were meaning to ask about sealing the ends of your line with a match. There is indeed a "machine" that does this much better and easier. It looks like a solder gun (in fact it is a solder gun) with a special attachment on the end that burns through synthetic line, thus cutting and sealing it at once.

Image

George

Edit: oops! It was Plymouth where we hiked. Portsmouth was nice also and we got to do something that every sailor should experience... we sailed the Solent on a beautiful blustery sunny day! :)
George and Kerri Huffman S/V Marquesa Freedom 40 CC CK Sail MarquesaImage

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Castaway
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Joined: Sat Dec 13, 2008 8:40 pm
Location: Lerwick, Shetland Isles

Re: wishbone sails

Post by Castaway »

We also tie our leeches up with 4mm stuff; I inevitably found the odd one or two would come undone and fall out (I'm too puny to do the knots tightly enough – aaahh!). To avoid losing the tie, I found it expedient to put a third knot between the sail plies. This doesn't affect the set of the sail, and it's easy to spot loose ties when you see one streaming from the leech. It also halves the effort of putting in a replacement.
Gerald Freshwater,
s/y 'Castaway', (UK F35 cat ketch, centreboard, 1987)
Lerwick Boating Club
Shetland Isles, Scotland

katorpus
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Joined: Thu Dec 04, 2008 10:51 pm

Re: wishbone sails

Post by katorpus »

I've never sailed with the two-ply sails, so I don't know what I'm talking about there but...

It seems like you'd leave these tied when dropping the sails and only untie them when pulling the sails off of the boat completely.

If that's the case, a quick stitch through the bitter end of the line (up close to the knot and "catching" the knot with the stitch)... with a piece of waxed whipping thread... would hold it all together and be easily cuttable to remove the tie when the time came...

A contrasting color of thread would make the thread easy to locate.

Just a thought.

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markedwards
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Re: wishbone sails

Post by markedwards »

Vanessa,
Michel is correct. I won't elaborate on his answer other to say that the reason for the loose tie between the two plies of the wrap-around sail was so that they would not fan open when gybing or sailing downwind. You don't have to over-think the connection. The grommets can be secured with a light line and loosely, say 6-8" or so. Mark Edwards

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