I wouldn’t expect to live long on a small boat in the ocean even under normal conditions - if we got away before the plague hit, it seems we wouldn’t get it. I mean if me alone on a boat wouldn’t, then we together on a boat wouldn’t either. If you mean it’s already in us and we don’t know who becomes symptomatic, then I would isolate in case I was a zombie, hopefully with some sort of means to self destruct if so.