Naah, actually mucked about on boats a little, but only ever as a passenger / deckhand, never captain. (Let alone owner!)

One thing I do know, having read too much Hornblower (and Bolitho etc) in my teens, are the names of most of the various ropes on sailing vessels. The best bit of this knowledge is that: Sometimes, when you know them better than the actual owner/captain, you can annoy them by using the correct term when they ask you to "pull on that rope there" -- "You mean the foresail reef?" But the general method, in case they know them, is of course to go all "You mean this piece of string or that piece of string?" You can drive your friends Captain Haddock apoplectic that way.

[EDIT:] Hmm, come to think of it, I haven't got all that many invitations to come be a deckhand in recent years. I wonder why... [/EDIT]