trimming jib

I went out with new crew last weekend and when we tacked after the jib was sheeted in on the new tack they kept reaching back and tensioning the jib sheet on the weather side. They said this was to shape the sail better. I always just uncleat and let go on the jib sheet prior to tacking, and sheet in on the new leeward side, until telltales stream back, and don't bother with the other side...is there anything to this messing with the windward sheet line to curl or further "shape" the jib optimally?

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eddiecat

Nacra 5.0 (destroyed in storm)
Hobie 16 (restored)
Nacra 5.5- amalgam "Franken Cat"
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was this on upwind, downwind or both?

doesn't seem right to me. if you sheet in on the weather side you will be miss shaping your jib (by pulling the clew inward).

if they were trying to "close the slot" (bring the jib closer to the main) this should be done with the traveler on the beam.. not by pulling the jib clew.

Thanks Andrew,didn't seem right to me either but being a newbie I thought I'd be PC and let it go
yes; after tacking and sheeting in the jib to leeward, they would then sheet in on the weather side, seemingly "tightening" the jib, but I guess I do that by sheeting out until it luffs, then sheeting in and cleating off when sail quits luffing. I just let the windward jib sheet stay loose, and as you say adjust the slot by using the jib traveler.
BTW this was a mono-hull type person....maybe that explains it icon_rolleyes

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eddiecat

Nacra 5.0 (destroyed in storm)
Hobie 16 (restored)
Nacra 5.5- amalgam "Franken Cat"
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admitted newbie to site but have a few miles under my keel on monohulls. I have actually done this on my P16 rationale being to allow the top of the jib to twist. The jib traveler allows the sheeting angle to change wrt centerline of boat but it doesn't allow you any fore ad aft adjustment. This is desirable to adjust foot vs leech tension and allow sail to twist. Given the small size of H16/P16 jibs it is probably not a big deal but because the apparent wind angle changes with height above water one often wants a twist in the sail at the top to get proper angle to the wind. As I say I have done it on my P16 to get both sets (upper and lower) telltales streaming. Only on a beat/close reach though. And to really make it work you should actually slightly undersheet the lee side and then tension (a bit) the windward side. Result is less leach tension.
Thanks hydroghyl I'll give that a try this weekend

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eddiecat

Nacra 5.0 (destroyed in storm)
Hobie 16 (restored)
Nacra 5.5- amalgam "Franken Cat"
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Not usually a good idea unless you really do want to slow down like at the start or to help get around during a blown tack. But to go fast the slot wants to be open. Ever notice how slow it is when the jib doesn't clear the halyard and you can't figure out why the boat is slow. Other wise simply pull the jib in tite or travel out down wind and trim the tell tales.
It's wortha try eddiecat. As I implied it is a bigger deal on large masthead rigged monohulls but playing with the sail trim is always worthwhile. If it doesn't work stop doing it.

bwilson - agreed opening the slot is important. particularly at the middle third (vertical) of the main where much of the power is. which is why I think you will find that on occasion (beats & close reaches in lighter winds) allowing the top of the jib to twist off will open the slot at the top of the jib. for a given course and boat speed an increase in wind speed pulls the apparent wind aft meaning that the top of your jib will be over trimmed and your slot a bit tighter than ideal.
On my 5.8 when we are trying to sail as close to light wind as possible, I have done this. On the 5.8 the jib track is fore and aft, by pulling on the windward side I can move the clew about 4" toward the center of the boat. See page 8 to 10 in this Prindle manual for the 4 way jib sheet upgrade. http://www.performancecat…/Prindle1918-2Manual.pdf
It is slower sailing this close to the wind, but sometimes a slow straight line is faster than two tacks.



edited by: skarr1, Sep 08, 2009 - 09:00 PM