Re: Need to identify Mark Twain boat.
Freshwater vs. Saltwater just means "where has it been mainly used". However, an important part would be whether yours has closed-cooling or raw-water cooling. The salt water can be harder on engine parts if you have an open cooling system. Since MT's were mainly built in Missouri, I bet that yours is open cooling. It is definitely a big enough/solid enough boat for the ocean though, so I wouldn't worry about that. If the engine is reliable, go for it, just make sure you have the proper open-water equipment like radios, flares, etc in case an emergency occurs.