Back in grad school my roomie and her bf started to build a rowing scull in our basement. I made a crack about getting it out and they said "Oh no, we checked - the keel barely makes the corner." Then I measured "by eye" as they say and asked "what about after it actually has beam to worry about?"
A flurry of worried glances and tape measuring followed.
And they moved the project to HIS basement.
-dale