Gibbs reveals he burned the boat he was building in his basement six years ago. Director Shepard surmises he named it after an ex-wife, whose name he reveals as Diane. I don't know information about the other boats he had built.
ok i know that this is a two year old post.....BBBUUUUUTTTTT>........ When Dr Shepard is talking to gibbs she says is that the same boat and he says he had to burn it b/c he named it after an exwife...he never stated that he burned it in the basement....something that large would burn his whole house down....I still like the "Break the bottle" answer but gibbs did speculate that he would probably knock a wall down when he was working on the boat with the survivalists son in a previous episode....there is no real answer that was ever stated and i have watched every one of the first 8 seasons episodes at least 5 times per episode...it is hands down my favorite show!