weather helm

[tha3rdman]

Try this again, after some confusion, Here is #97's 1989 sails with wind in them. Being as I'm not sure exactly what I'm looking for as to if, it is her weather helm issue. Your opinons are as always appriciated.

[tha3rdman]

Here is the leeward side of the same sail, same tack, same wind.

[bill@ariel231]

take this with a grain of salt since I'm not a sail maker...

It looks like there is some stretch in the sails in the photo you posted. It's not the only cause of weather helm but it can be a contributor. By the way, a bit of weather helm is desirable (safer to round up in a puff than to fall off). As a rule of thumb, Alyce and I either drop the traveler/main sheet on a puff and drive off the jib or if the wind is steady and over 15kts we'll reef the main. Generally, we don't see more than 15-20 pounds of effort at the end of the tiller.

I've marked the areas that may have stretched on your main. nothing terminal for cruising, you may want someone from a sail loft to take a look this winter.

The dashed red line shows a break that may indicate the sail has lost some shape (this may not occur at all wind speeds)

[bill@ariel231]

The break may be more noticeable from the leeward side.. and you'll need to take a close look under way.  I'm using the shadows from the seams to mark two possible shapes... if the shape of the main matches the red curve, the sail has stretched, the trailing edge has cupped and the center of effort has moved aft. If the shape matches the green/blue line, the sail still has most of its life ahead of it...

of course, if you aren't racing for glory&beer every tuesday & wednesday night, the issue is mostly academic.  

cheers,
bill

[Theis]

Have you tried putting pennants (telltales) on your sail or draftlines (I think they are called). Tell tales you can get at west for afew bucks and you spot them across the sail at a couple different levels on each side.  They can tell you where your sail is luffing or too full.  The draft strips across a couple levels of the sail can best evidence where the sail has a crazy shape.  I think the tape is available at West

[tha3rdman]

Got the tell's seen the options for draft stripes in new sail quotes, the pictures taken are with the tells in the straight back position (ie good sail trim)

Thanks to bil for pointing out how a sail shouldn't look, I assumed that the break was caused by the battens.

[bill@ariel231]

one thing you may want to check is that the battens aren't in backwards. the thin end goes forward. with the batten in backwards, I've seen the break come early on an otherwise good sail.

this sort of problem will cost speed (10th of a knot) but to small an effect to drive weather helm

[tha3rdman]

The battens aren't the tapered style, they we're on the boat when i bought it, I belive they are 1.25 but truthfully i havent measured them.