Gaff sail used as balanced lug (with apologies)

[JimD]

Apologies offered for bringing up another topic that has probably already been beat to death, but here goes...

I have the dacron panels for a sailrite sail for this dinghy:

http://www.woodenboatstore.com/images/400050.jpg

I never did get around to having them sewn into a sail but now might be the time. Could this sail be used as a balanced lug rigged kinda like this?

http://intheboatshed.net/wp-content/uploads/2007/08/balanced-lug-sail.gif (http://intheboatshed.net/wp-content/uploads/2007/08/balanced-lug-sail.gif)

Is the peak too high? What other issues am I looking at? I want a sail that is easy to raise and lower and build in the first place to assist our 15 foot Glen-L Minuet converted into what is now essentially a power boat with sail assist (See my other thread on Bermuda rig to sliding gunter http://www.woodenboat.com/forum/showthread.php?t=94364

[Todd Bradshaw]

That might be pushing things a bit too far to really work well. The peak angle is awfully steep, considering that you want to generate good downward force at the aft end of the yard (combination of halyard pull and gravity - helps increase luff tension and also helps keep the yard's angle stable). You would also probably want to cut off the luff round on a dinghy-sized sail and have a straight luff. Even with 4 oz. cloth, there is often not enough luff tension present on small lugsails to pull the round straight and force it into becoming a draft-producing feature (especially since any lugsail's luff should be pretty heavily reinforced - 5-layers thick isn't unusual). Without a luff re-cut, you might wind up sailing around with a curved luff that's not really doing anything in the way of contributing draft or shape and which may be prone to flapping, fluttering or "wind-seeking" - where it slowly and continually flops back and forth, port-starboard, trying to find a suitable angle of attack to support its shape.

I suppose, since it's not been trimmed-out yet, you could re-cut the top at a shallower peak angle with a bit of head-round, re-cut the luff straight and see what it yields, though it will most likely be a bit on the flat-ish side through the middle and down low. It might be easier to eBay the kit and start over with a new one.

[JimD]

That might be pushing things a bit too far to really work well...
I suppose, since it's not been trimmed-out yet, you could re-cut the top at a shallower peak angle with a bit of head-round, re-cut the luff straight and see what it yields, though it will most likely be a bit on the flat-ish side through the middle and down low. It might be easier to eBay the kit and start over with a new one.

Thanks, Todd. I doubt if I'd get half my money back on eBay so a little trimming and cutting makes more sense to me - or just use it as the gaff sail its already cut for and not be so lazy about the small amount of extra work required for spars and rigging :o:)

[johngsandusky]

I am not disputing Todd.
I have used a gaff sail as a lugsail. I think mine was lower aspect. It was a second-hand sail, I adapted it to a marconi dinghy with a 2x4 mast and bamboo spars. It seemed to work well enough, but the boat was stolen before I really had enough experience to detail it's abilities.

[JimD]

Whatever sail I decide to use the boom would have to swing over the new appendage on the cabin top. Perhaps I'll start a new thread...:o

http://im1.shutterfly.com/media/47b9dd38b3127ccec6f3b9dd1ae600000040O00CbOGrVu4cMQ e3nw8/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

http://im1.shutterfly.com/media/47b9dd38b3127ccec6f295173a7600000040O00CbOGrVu4cMQ e3nw8/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

http://im1.shutterfly.com/media/47b9dd38b3127ccec6f2a7e83a9000000040O00CbOGrVu4cMQ e3nw8/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/