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post #1 of 5 Old 04-21-2010 Thread Starter
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Smile A Question for sail

these days i learn how to sail on the net ,and learn how to buy a sail ,i have a question about this setence "genoa with an LP of 150% and they are nearly 300% bigger than a non overlapping genoa."what does it mean "lP'
thank you for the people who gives me answer.

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post #2 of 5 Old 04-21-2010
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See here

Pretty much any measurement you might need is shown and defined on that page.

BTW, LP stands for a line that passes through the clew and is perpendicular to the jib/genoa's luff. If this line is 1.5 times the length of the "J" measurement, then it is usually considered a 150% genoa.

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Last edited by sailingdog; 04-21-2010 at 09:41 PM.
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post #3 of 5 Old 04-21-2010 Thread Starter
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thank you ,it is very useful.

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post #4 of 5 Old 04-21-2010
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Quote:
Originally Posted by hlmffsailmaker View Post
"genoa with an LP of 150% and they are nearly 300% bigger than a non overlapping genoa."
This seems pretty unlikely.

Imagine a genoa that fills the foretriangle without overlapping the mast. Now make a copy and hang it from the mast with the tack pointing aft, so that it looks like a big tall fat mainsail. Now sew the two copies together along their leeches.

This Frankensail clearly has an LP greater than 150%, an also clearly has only twice the area of the original non-overlapping genoa. Even accounting for the curvature of the surface I'd be surprised if this claim were true. On my boat with I=34.5 feet and J=11.3 feet, I would need a 188% LP to double the area of the genoa.

I'm guessing the author of that claim is comparing an overlapping genoa to some kind of high-clewed jib.

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
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post #5 of 5 Old 04-22-2010
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I'd point out that any headsail that doesn't overlap the mast is considered a JIB... Genoas are just headsails that extend past the mast... or oversized jibs...

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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
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