Would you consider building in foam core instead of plywood? It's more
expensive of course, but the boat would come out weighing approx 1/2 as
much. The boat would sail *much* better and be easier to handle overall.
You could then add ballast for stability and still have a lighter better
boat. No worries about rot, either.
Its not something I had really considered yet. I did have a quick look for
foam core suppliers in the UK and I couldnt find any with reasonable prices.
Maybe they are out there but I couldnt find them
Not only is foam pricey its not a construction technique everyone is
comfortable with. If you have experience with a plywood boat I would
be inclined to stay with it. As for rot, epoxy encapsulation is quite
effective at dealing with that.
I looked at the kingston well when choosing designs (I settled on the
need to design my own but that is definitely not for the faint
hearted). There was a lot to like about it. For a second boat, it
should make a nice project.
These guys also have 3 very simple plywood trailer sailers, a bit
bigger and more comfortable than the kingston.
http://www.stevproj.com/PocketYachts.html
Weebles Wobble
(but they don't fall down)