QUESTION:
My wife and I and our children will be cruising on her parents 50 foot ketch for one year in the South Pacific. What documents do we need on board, specifically since we are the operators and not the owners?

ANSWER:
You will need passports, of course, and you will need proof of registration/ownership of the vessel. Because you are not the owners, I think it would be prudent for you to have a notarized document signifying that you are the skipper of the vessel, signed by the owner, though I'm not sure how important this is. Is the boat federally documented, or just state registered? You might check with the US Coast Guard web site for some guidance there if it is a documented vessel.

http://www.uscg.mil/USCG.shtm