After the fascinating discussion on spinnaker lift versus 'leveraged bow dive', I'm still left wondering...
How far does the spinnaker pole need to be past the bridle to give at least enough lift to cancel out the bow-dive. Preferably, I'd like a little more lift than dive so crew position could be more flexible.
Since the bridle is where the pole will be lifting from, that is where the measurements should be taken. Also, since we are taking into account a vast number of different boats, with different distances from their forward beams to the bridles, it is the only way to communicate this issue in a fashion that covers them all.
G-Cat 5.7M #583 (sail # currently 100) in Bradenton, FL
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Re: How long should a spin pole be?
#13679 12/03/0203:31 PM12/03/0203:31 PM
Technically, the measurement should be taken from a point directly below the hound on the mast, as the amount that the chute "lays back" determines the angle of lift; that is, what percentage of the lift generated is vertical versus horizontal. With a pole length of zero, all lift is horizontal and you are talking about your main sail. The Aussie 18 skiffs use very long poles, and frequently triple-trap off the rack which extends 2 feet or more aft of the transom. http://www.18footer.org/Galleries/D...ternational_Championship_2002&Page=2 The boats would reverse-pitchpole if they tried that upwind. This is why we run footstraps on kite cats, very often. The short answer is "very long", and the other short answer is "it depends". It depends on the size of the sail, how much air there is, how much lee helm you can stand, and how much pole you can stand. Like I mentioned in an earlier post, some classes limit the length of the pole. All that said, I have sailed my P-19 with small chute with 11' and 12' poles and could not tell a difference; I am in the process of rigging a 15' pole now, with a larger sail, and I'll fill y'all in. I figure with modest rake, the tack will be about 16' ahead of the head, and since the luff is about 31', this works out to about 40 degrees of angle on the luff. I think.
pix upcoming, and I'll take it sailing in the spring sail fast y'all
I want to know how you do it so I can get some ideas. I havent been able to figure the best solution out with the front beam, but it seems that should be a benefit. I know the front tramp will be a benefit as you can sew a snuffer bag right to it.
If you ran it from the main beam over the top of the front x-beam(where it could be supported side to side), then out a distance(to be decided) then supprted at the end by 2 side stays and a compression stay?
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