Doc, As long as the numbers are in the right place and there is a registration sticker, just about anything goes as far as the name goes. It’s not like a license plate. You can use suggestive wording or slang in your boat name.
The thing with boat names though, they are usually done in a “style” I would compare to retro hot rod. Lots of multiple outlines with drop shadows and the look of “speed.”
Something like these (these guys do rad wraps too):
http://www.signsunlimitedkw.com/?page_id=122
HickWorks, your original sketch actually has a lot more going for it than your machine iteration. Something got lost in the translation. In the sketch, the letters relate to each other in a rather nice way. You sort of drifted from that when going to vector.