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.
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...
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
Andrew, Thanks for the link.
Wow, Great pics! The size of those chutes is scary!
Longer is better, sure, but you have also to keep a reasonable steering balance. Too much leehelm due to a too long pole can be very annoying.
the 12s hold the best ratio pole to boat length..
try http://www.skiff.org.au/
12 foot hull up to 14 foot prods and up to 30 foot masthead kites
[color] >>the 12s hold the best ratio pole to boat length..
>>try http://www.skiff.org.au/
>>12 foot hull up to 14 foot prods and up to 30 foot masthead kites
Notice, too, the two sets of spreaders on the mast.
And a set of spreaders on the spi pole 1
Not to mentions the excellent conditions of those maniacal sailors due to their watertime which is disproportional bigger than their air time ?
How many of us have tried to sail these exciting boats, and how many of those have succeeded at it ?
Mind you their is one for sale here in NL for only 800 euro's, I'm pretty tempted.
Wouter
Australian PN system ratings called VYC
12 foot skiff 92,0
Taipan 4.9 73,5 (no spi)
Tornado 69,0 )no spi)
Big kites don't always make you faster.
12 footer dies on waterline length against 16 foot boats.. A better comparison would be 12s vs Kitty Cats (can you look that up on the vyc yardstick dont have time)
16teens arent unlimited skiffs (neither is the 49er) So a fair comparison in the 16 foot length isnt available.. Although around the standard 49er course I doubt if that many cats will take one..
One can compare 18 footers vs F18HT and F18.. My guess is the F18 will lose the F18HT may be about the same or a little faster..
As for spreaders.. 12, Javelins(14 foot), 14s all have twin spreader rigs if not triple.. 16 & 18s have three or even 4 spreaders..
This is all well and good but it's not giving me any of the answers I'm looking for 
Don't you use a seperate hound for the 2nd headsail halyard?
For my specific application: I have a G-Cat 5.7M and I want to run a r/f reacher on it. The spin poles will be a V shape arrangement coming off the bow x-beam (beam not foil)
I've attached a (very) rough sketch of what I want to do. I'll be using two lower windsurfer mast sections.
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.
Send me some pix when you get it going,
Dave mosley
G-Cat 5.0 # 507
www.seacats.org
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?
Dave Mosley
Then I'd waste all the lounging room on the front trampoline and I'd lose a lot of jib sail-area by having to attach it high at the bridle instead of low at the bow-beam.
I'm going for- max sail area (light winds prevail around here in the summer) and max lounging area (beautiful women abound around here in the summer... 
)