Thank you Pete,
I must admit I never thought of thinning down epoxy. Must give it a try. I have used fiber glass resin, no matting, but it is very brittle unless a filler, like talc, is added.
Yes, it is quite ambitious. I'm still working out the logistics of the barge - it needs to be about 12 foot long and 2 foot beam. Opposite problem to Mr Darby - it has to be as light as possible, otherwise I'll never get it up onto the roof rack!! Oh well, I've got all winter to work it out. Will post pictures once I make progress beyond the planning stage.
Regards, Paul