Mast step for balanced lug sail

[Jon V]

I'm a longtime canoe tripper, but new to canoe sailing. This past summer, I put together a workable sailing rig for my old 20-foot Grumman and fooled around with a smallish four-sided sprit sail. Since that requires the mast to rotate in tacking, I installed a round mast step. I'm now in the process of upgrading to a larger balanced lugsail--a real one this time, in place of the homemade tape-and-Tyvek original. Since the lug sail mast is not supposed to rotate, I'm wondering if I can retain the round mast step. Will the tension of the downhaul be enough to prevent rotation of the mast? Or should I replace the round mast step with a square one?

Honesty compels me to state that the canoe is question is not a beautiful wood and canvas boat, but an old 20-foot Grumman. I hope that will not subject me to scorn, but if it does I suppose I can bear it.

 

[Benson Gray]

I'm wondering if I can retain the round mast step.

Yes, Old Town sail rigs had round holes in the mast steps until the 1930s before they were replaced with square ones. Some minor rotation may not be an issue with your lugsail. Good luck,

Benson

 

[Jon V]

Be

Yes, Old Town sail rigs had round holes in the mast steps until the 1930s before they were replaced with square ones. Some minor rotation may not be an issue with your lugsail. Good luck,
Benson

-
Thanks, Benson--that's good enough for me.

 

[Todd Bradshaw]

It's one of those "try it and see what happens" things. The main reason some sail types favor a rotating mast is that it can keep the halyard tension consistent from tack to tack, which is usually good, rather than being slightly tighter on one tack and slightly looser on the other. Lugsails are all about maintaining high luff tension. It is critical to maintain it for decent sail shape and stability. The combination of halyard tension, pulling upward on the yard, and thus also the luff edge of the sail, and downhaul tension pulling downward on the luff from the tack corner are what keeps the luff tight and the sail working properly. Signs of inadequate luff tension would be the yard dipping at its aft end when the mainsheet is eased and/or the leading edge (luff) wandering back and forth trying to find a stable place with relation to the wind direction. So, a mast that can swivel slightly from tack to tack should not cause any problems as long as the downhaul's anchor point is on the mast and can swivel with it. If, on the other hand, the downhaul was anchored to the deck, floor or other non-mast parts of the boat you might see the downhaul tension change a bit when tacking.

Do be aware that the yard of any lugsail needs the halyard attachment far enough forward that the yard feels quite "tail-heavy" when you go to raise the sail. This is to help maintain maximum luff tension at all times, whether the mainsheet is tight while sailing, or temporarily loose when tacking.

 

[Jon V]

Thanks, Todd.

It's one of those "try it and see what happens" things. The main reason some sail types favor a rotating mast is that it can keep the halyard tension consistent from tack to tack, which is usually good, rather than being slightly tighter on one tack and slightly looser on the other. Lugsails are all about maintaining high luff tension. It is critical to maintain it for decent sail shape and stability. The combination of halyard tension, pulling upward on the yard, and thus also the luff edge of the sail, and downhaul tension pulling downward on the luff from the tack corner are what keeps the luff tight and the sail working properly. Signs of inadequate luff tension would be the yard dipping at its aft end when the mainsheet is eased and/or the leading edge (luff) wandering back and forth trying to find a stable place with relation to the wind direction. So, a mast that can swivel slightly from tack to tack should not cause any problems as long as the downhaul's anchor point is on the mast and can swivel with it. If, on the other hand, the downhaul was anchored to the deck, floor or other non-mast parts of the boat you might see the downhaul tension change a bit when tacking.

Do be aware that the yard of any lugsail needs the halyard attachment far enough forward that the yard feels quite "tail-heavy" when you go to raise the sail. This is to help maintain maximum luff tension at all times, whether the mainsheet is tight while sailing, or temporarily loose when tacking.

I had planned, in my innocence, to anchor the downhaul to a cleat on the mast thwart, figuring that it would help prevent the mast itself from turning and also that it would be desirable to keep it from turning. But maybe I should anchor it to a cleat on the mast instead and let it turn. I've lived most of my life so far by trial and error, so I'm comfortable with applying that principle to canoe sailing rigs also.

Thanks for noting the importance of a halyard attachment that leaves they yard "tail heavy." My existing mast is, I think, just long enough, and I would really like to avoid making a new one. Keeping the halyard forward on the yard should help out with that.

By the way, I love it that you often chime in on various forums when the subject of canoes and canoe rigs comes up. I have enjoyed your book.