They use lines similar to that on the Thames barge four sided sprit sail, but they call them sprit vangs and they attach them to the gunnels about halfway between the mast and the sail leech if the sail was centered fore and aft. As well as keeping preventing sail twist, they do double duty to prevent accidental gybing.
But, when it comes to sail twist prevention in small boats, I think that's why Phil Bolger was so keen on the three sided sharpie sprit sail.
I'd like to reduce twist in my lug sail, but I can't see any practical way to do it, apart from using multi-purchase downhauls like Mik Storer recommends. Like everything in boating, sail choice is a compromise and I love balanced lugs ease of reefing.
--- In Michalak@yahoogroups.com, John Boy <t1ro2003@...> wrote:
> That's what I'm thinking the only difference is my mast is not offset, I centered it up. Â BTW there is such a thing as a gaff vang and I've thought about giving it a go just for fun. Â Tie a line to the peak and run it down through a block tied to the top of the mizzen mast. Â Then turn it at the bottom of the mizzen mast to a jamb cleat.
> John Boy