First off, you asked the same thing in two different areas of the forum. This is generally referred to as "spamming" and is frowned upon. That said, there are several kinds of "scale" boats. Are you talking ships(warships, cruise ships, sailing ships, etc), scale racing boats(offshore, hydroplane, crackerbox, etc) or did you have something else in mind? Something else you have to consider is what kind of power are you looking at using. There's gas, nitro, electric and wind.