JIB BOOMS

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Alistair
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Location: United Kingdom

JIB BOOMS

Post by Alistair » Tue Nov 16, 2010 10:15 pm

Have been thinking about rigging my jib boom in a different way and found in Eric Twinames book sail race win a photo of him sailing a canoe with a jib boom with what looked like a self tacking jib track as well, does anyone know how this was rigged, or have a better picture of it.
I am still not sure that my jib boom really adds much but I am keen to keep it and would like it to be a bit neater, as rigged it does not do anything upwind,but helps to hold it out off the wind which I think is the right way, but I would like to get rid of the line that goes back up the mast that acts as the vang.
Any ideas?
Alistair

Chris Maas
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Location: USA

Re: JIB BOOMS

Post by Chris Maas » Wed Nov 17, 2010 5:31 pm

Hi Alistair, I have been trying a carbon wishbone jib boom that is one sided. It pivots on a sleeve that is sewn onto the jib luff tape about a meter up from the tack. Like your boom it doesn't do anything upwind but does make for a nice looking sail offwind. I didn't spend much time with it sailing against other boats so am not sure if it's fast, but how could it not be?
I've since moved on to a MUCH wackier way to deal with the jib downwind that may be unveiled at the Worlds, if it works.

Alistair
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Location: United Kingdom

Re: JIB BOOMS

Post by Alistair » Thu Nov 18, 2010 7:47 am

Hi Chris
Thanks for that. Good luck with the experiments, I think there will be lots of new boats at the worlds, should make interesting racing!!
Alistair

SteveC
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Re: JIB BOOMS

Post by SteveC » Thu Nov 18, 2010 9:26 am

Chris Maas wrote:I've since moved on to a MUCH wackier way to deal with the jib downwind that may be unveiled at the Worlds, if it works.
Chris,

I'm guessing this wouldn't involve extending the jib pole about 2m out the front, tieing a large floppy jib to the end of it and pulling it to the top of the mast :lol:
Steve Clarke (UK)
GBR338 "Money4Nuffin

Andy P
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Joined: Thu Sep 08, 2005 9:31 pm

Re: JIB BOOMS

Post by Andy P » Sat Nov 20, 2010 4:43 pm

But it might be a N12 style dangly pole ? . These give good leech control reaching or downwind.

jimc
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Re: JIB BOOMS

Post by jimc » Sat Nov 20, 2010 10:24 pm

Andy P wrote:But it might be a N12 style dangly pole ?
I've been having a lot of trouble getting mine set up right. The trouble I'm having is that if I make the jib sheets long enough for deep reaching/running then they are much too long for semi automatic jib sheeting when tacking. Short of having some kind of adjustable sheet take up in the plank, and I try and avoid that sort of complexity, I'm having to take a hit on the deep reaching in order to be able to tack reasonbly readily.

Alistair
Posts: 243
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Location: United Kingdom

Re: JIB BOOMS

Post by Alistair » Sun Nov 21, 2010 10:38 pm

Hi
I tried the n12 style dangly jib boom on 240 a few years ago and it worked very well. I solved the need for extra jib sheet length by having the elastic on the end of the jib sheets on a clip that I could undo, bit diffcult to describe, the elastic came from the ends of the seat where it was attached to the jib sheets and came through an eye in the center of the seat, to tension the system the center of the elasic was pulled through the eye at the center of the seat and clipped to one end of the seat (both ends of the seat had a clip for this so it cold be done on either tack). The problem I found was that you had to clip this elastic back on after the reach and also you need to adjust the dangly stick when you adjust the jib sheet. So all in all it was a bit of a faff but it was better than the jib boom (well I think). Perhaps I could do a combo of the two systems?
Alistair

Steve Clark
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Joined: Fri Aug 01, 2003 2:26 pm

Re: JIB BOOMS

Post by Steve Clark » Mon Nov 22, 2010 11:32 pm

I have solved this two ways:
First I increased the uptake inside the seat. There was enough friction in the bushing at the end to tack the jib, but not so much that I couldn't yank out extra scope for the runs.
Second effort was to put a block on the bungee and lead the sheet tail through the block and then back to the carriage. Thus the seat had a 2:1 or 1:2 ? effect on the jib sheet. In any event you had more string when the seat was near center than you had otherwise...
Both seemed to work.
SHC
Beatings will continue until morale improves

jimc
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Re: JIB BOOMS

Post by jimc » Mon Sep 02, 2013 6:09 pm

Finally (since Europa cup, where it still wasn't right) got my dangly pole working pretty much to my satisfaction... I needed far more slack in jib sheets than I guessed. What has worked for me is close to what I understand of Steve's second suggestion - the sheet goes through the end of the plank, through a slot in the bottom of the plank down to a block attached to the carriage, and then back to the plank again. The point where the shock cord exits the plank and returns to it should ideally be above the block when on the opposite tack. Having the plank about 1/3 across seems to work OK for getting the right amount of slack in both sheets.

Whether its better or worse than the club foot arrangement on Alistair's and others' boats I couldn't say. I don't think the dangly pole is compatible with a self tacking jib, certainly not if one is to get the best out of the options available for sail shape. Both setups have their advantages and drawbacks. I deplore having the pole wandering round in the slot, but don't like the idea of a much longer string creating turbulence ahead of the jib either.

jimc
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Re: JIB BOOMS

Post by jimc » Mon Dec 02, 2013 12:59 pm

On the jib boom thing, here's a thought. Supposing you rig up a sort of two legged arrangement with a leg each side of the jib, and meeting say about 200mm up the jib luff, and run the twist control line to that, rather than right up the mast. Maybe something like this?
Image
That might get round having that horrible line right up the jib luff. OK, there's a bunch of mess and drag round the foot, but it must be much less than all that line... I can't try it on my boat because a jib foot spar wouldn't clear the foredeck, and I don't really want to rip off the foredeck right now...

Mal Smith
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Re: JIB BOOMS

Post by Mal Smith » Sun Dec 08, 2013 11:40 pm

jimc wrote: ....That might get round having that horrible line right up the jib luff. OK, there's a bunch of mess and drag round the foot, but it must be much less than all that line... .
Jim, I don't think so. If you take into account the angle of attack, the jib boom vang line is well to leeward of the jib and is unlikely to effect the boundary layer to any any significant degree. The drag of the line is also pretty insignificant.
AUS019

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