Thanks everyone for all the input and the link to the svenson site! My boat looks a lot like "Canvas Back". I think I'll start by trying to remove the outer wooden keel. It's screwed into an inner wooden piece and some of the screws are backing out a little anyway so I suspect it as one source of leaks. Assuming it comes off ok and everything seems sound, what sort of sealant would you recommend if I reassemble without re-skinning? Silicone? Boatlife? Thanks again.