I give the post and corner casting a painted on coat of epoxy when glueing.Assemble,then turn over the boat,square it up, and drip epoxy into the voids. It takes some time but they fill up nice and the boat stays tight. My theory is that the coating helps prevent the metal to metal corrosion. The casting then can be heated and the boat will come apart with a dead blow hammer as Matt M. said. I have more trouble taking apart old unglued boats then the ones I've glued.
Take a kid out sailing. I hope all you 16 guys are coming to the Madcatter.