On Nov 20, 6:12 pm, cavelamb himself wrote:
Take a look at the mast mounting here...http://www.amateurboatbuilding.com/a...der/index.html

Use the sail only off-wind so you can use a boomless gaff rig thus
keeping the sail low and eliminating the need for stays. I'd use
leeboads instead of a centerboard because with a centerboard you need
more structure under the mast to support the loads on it whereas with
leeboards those loads are on the pontoons.