Targans post on the alternative fuels thread made me think of the water craft local to my Area. In Maine we have special fishing boats called Lobster boats which you can guess by the name are for lobsters fishing or "buggin" as they call it. Anyway these boats are extremely sea worthy craft! That can travel at high speeds if necessary to bring in the catch. They can also carry a large amount of traps (pots) and gear.
I can imagine these could easily be retrofitted with crew served weapons and be used as Patrol boats for blue or brown water.
check one out.
http://www.youtube.com/watch?v=Acq2J...eature=related