I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my
neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic
crossings). The companionway door was latched and locked - he was baffled because the
door had never latched in his experience (he's had the boat a year and always locked with
an external padlock). After a while we were able to pry it open and figure out what had
happened.

On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the
latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16
inch of flexing.

Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner
said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when
we unrigged her that it opened a deck leak."