In mast furling and clew

[eisselhardt]

So, I have a 2010 Beneteau 43 with in-mast furling that I've had for two months now. We've sailed her quite often, but I notice that when the sail is fully unfurled, the clew is much higher (measured from the boom) than the tack--maybe a foot or more higher. At first, I thought the sail was installed at an angle in the mast, but on inspection it is clear that the luft is even with the mast all the way up.

Is that foot's diagonal run from tack to clew how it is supposed to be? I had an in-mast furling rig on my Bene 381, and the foot ran pretty much parallel with the boom.

Thanks!
Eric

[Faster]

Picture???

[Alex W]

It's a stupid question, but are your vang and mainsheet free (with the topping lift holding the boom up) when you unroll the main? The boom should be able to angle itself on the gooseneck to meet the shape of the sail.

[night0wl]

More outhaul tension!!!! My sail is flat/parallel with the boom too. When its not, its almost always because the outhaul has creeped loose through the outhaul spinlock cam-cleat

[eisselhardt]

Thanks, folks. I don't think it is either of those possibilities as the outhaul tension is tight and the sail luft is flat against the mast. I will ease the vang, but moving the boom up a foot or so at its end just makes for a pretty picture, but doesn't seem to answer the problem.

I suspect that the sail is simply cut in such a way that from tack to clew rises when the luft is flat against the mast. Seems remarkably inefficient, and maybe it is time for a new sail set.....

[Faster]

Without pics it's hard to say, but it does sound like your foot is cut at an angle that sets your clew high.. usually done to clear dodgers/biminis/arches etc. But I have to say that you'll get better sail shape and drive if you let the boom 'rise' to the clew by further tightening your outhaul and easing the vang. A 2-3 year old boat shouldn't need new sails quite yet.. You might talk to a sailmaker about modifying the sail for a better fit.

[azguy]

I'd love to see a picture...

[MSN2Travelers]

Can't speak to your specific model but on my B352 the clew is higher than the tack when the sail is fully deployed.

The vang and the main sheet have to be eased slightly so the boom can float when the main is deployed and/or furled. My guess is the boom is up-angled between 3 & 5 degrees.

I set the topping lift to hold the boom about a half inch above the bimini and the boom rides a couple inches higher with the main all the way out.

[eisselhardt]

Thanks guys!

I was out all day on the Chesapeake this past Saturday, and eased the vang and main to allow the boom to ride up to the sail clew. The angle looked to be about 5 degrees from tack to clew, but the performance was pretty good. (Sorry, having too much fun and totally forgot to take any rig pics!)

It does seem that by cutting the sail in that way (without a 90 degree angle at the tack), some sail area is lost and performance may suffer a bit. In any event, I've decided to stop worrying about it and just sail until I need new sails, then address the issue.

Thanks again for your thoughts!
Eric

[MSN2Travelers]

Next time you furl the main, look at the foot as it rolls up in the mast. If the Luff-Foot angle was 90 degrees, all of the "thicker" foot material would roll up on itself and potentially jam itself in the mast. By having the clew slightly higher than the tack (along with an eased vang & eased main sheet), the foot slowly climbs inside the mast and creates a more compact package inside the mast.

In-mast mains are for cruising. Serious racers should stick with a conventional main if you have an overwhelming need for every .1th of a kt of speed.