What was the background experience of these 3? Did they have much sailing experience? That the dinner was laid out, computer running, sounds like they went for a swim and forgot to put a ladder or rope over the side first. It's happend plenty of times before. The only thing that doesn't make sense is the sails were up but maybe they we becalmed, went for a swim and couldn't get back on board.

OR, they faked their deaths, jumped on a buddy's boat, and forgot to put the fenders away first...