With the support of a noble, I wouldn't say it's impossible. Many advies carry around recommendations to be lifted into nobility. The cream of nobility, no less. So I think buying a boat will hardly be a problem, if you have the money.
Fine so lets add ship buying to nobility then. While we are at it Advies should probably be able to buy Paraphernalia and units so long as they have recommendations as well, after all they have the backing of nobility. Hell if they have enough gold they should be able to buy a region and run it as paradise for the lower classes, after all they have recommendations.
