03-23-2001, 07:12 PM
If the wind was traveling east and you were in your sail boat and wanted to go directly north. What is the best or optimum angle your sail should be (from the vertical or horizontal)? Thanx
03-23-2001, 10:18 PM
Let's assume you are talking about a typical small yacht such as you might find used by your average sport sailor - fore-and-aft rig, single mast with a main and a jib. Technically, a sloop.
The point of sail you are describing is almost what is called a "beam reach". The only reason it isn't actually a beam reach is that that means sailing at a 90 degree angle to the APPARENT wind. If the wind is actually 90 degrees to your direction of travel, the apparent wind will be somewhat behind you, and you will be broad reaching a bit. Some background on points of sail:
Anyway, that isn't the question you want to ask. The optimum sail adjustment doesn't depend on a particular angle, but on a large number of factors, and is adjusted by observing the behaviour of the sail. As that site suggests, the basic technique in this situation is that you want to let the sail out as far as you can without it starting to luff.
In practice, for your typical small sailboat in moderate air, this will be surprisingly far out, with the boom sticking way the hell out over the water, and the wind definitely blowing far more across the sail than behind it. Very roughly, I would say about a 30 angle to the wind, but it's hard to judge, varies a lot, and, as I said, the exact angle is not what you're paying attention to.
Beam reach is the fastest point of sail for a fore and aft rigged vessel, BTW, or at least that's what sport sailing courses will teach you. You are getting optimum use out of your sail from the combination of airfoil and push.
03-24-2001, 11:37 AM
This is a duplicate of this (http://boards.straightdope.com/sdmb/showthread.php?threadid=64795) thread, so I'm closing it.
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