In my spare time, I am writing a science fiction novel. Mostly I write it for recreation, so I have no idea if it will ever be finished or published. But maybe some of you can help me with some ideas? One of the sub-plots revolves around two couples on a custom-designed boat. The boat was designed to provide everything that the two couples would need for one year at sea, without any contact with anyone else. I know very little about boats, so here are some questions:

What type of boat? How big? How should it be equipped (to survive)? What skills should the crew of four have? How can their skills/supplies compliment one another? How can this boat/crew defend itself against those that might want to board her/take her supplies without looking out of place?

I prefer to place more emphasis on the science, and less on the fiction.

Ideas, links, opinions are all welcome. BTW, the boat is financed by a very wealthy and eccentric man (think of Howard Hughes as a survivalist), but he is not on the boat. So, money is no object.

Thanks for your help.