Interesting to see that posting I made over ten years ago. Just to clarify, I was quoting from the great sail trim book by Tom Whidden (North Sails) entitled "The Art and Science of Sails" So... don't slam me because you have a different definition. Anyway, a section of his book discusses optimal sail inventory for racing and cruising depending on boat size, and he explains the numbering system thusly:http://forums.sbo.sailboatowners.com/showthread.php?t=39366
(found on Google with "#1 jib" in the search box, could have done from the search engine on this board, a great tool)
Another interesting way of describing sails is to name them.... so the #1 would be a genoa(again... light, medium, heavy), the #2 would be a lapper, the #3 is the working jib, and the #4 is the storm jib." headsails are also described by numbers, with the Number 1 being the largest sail. A #1 genoa for an IOR boat typically shows a 150% overlap. Such a boat might sail with three Number 1's, light, mecium, and heavy, which are distinguished by progressively heavier cloth and progressively flaatter shapes. (PHRF boats can usually sail with a 155 % geonoa, without penalty.) A Number 2 varies from about 130 too135 or even 140 percent; a Number 3 has an overlap of about 98 %. Incidentally, a 98% sail, like a Number 3, doesn not quite fill the foretriange and, as such, does not overlap the main." The Number 4 is usually designated as the storm jib. The quoted section was lifted from Tom Whidden's "The Art and Science of Sails"
You do not have to worry about these sails on your boat. The O'Day is a pretty simple rig with a pretty simple suit of sails. Unless you want to start a sailmakers health and welfare fund I suggest you stick to the basics. A well made dacron main and a jib that fits your local sailing conditions will do just fine. IOR style boats are going out of favor for exactly the reason that they need so many different sails. Most modern boats sport a fractional rig with a smallish jib and a big adjustable main.Great, Joe, now I'm still confused about spinnakers. Why can't it just be symmetrical and asymmetrical spinnakers. Why the gotta have code 0's, and gennakers, and cruising asyms, and drifters, and on my boat, Neil Pryde made a "spanker," which I assume was their brand of cruising asym...
Near as I can gather, there are different numbered asyms, which correspond to different levels of wind speed, and usually only matter to racers. I'm guessing code 0's are the biggest, and roundest, of the racing asyms, and as the number goes up, they get smaller, flatter, and probably heavier material. You'd hoist higher number asyms as the wind gets up.
Brian
The number system used in the article I quoted was for upwind sails and was written in the 80's. Reaching and downwind sails have no such continuity as far as numbers go... unless the skipper wants to assign an alternative system for the sake of the crew.Great, Joe, now I'm still confused about spinnakers. Why can't it just be symmetrical and asymmetrical spinnakers........ etc.
Brian