When it comes to underwater crafts, there are several different synonyms that can be used. Some of the most common include submersibles, submarines, bathyscaphes, and diver propulsion vehicles. A submersible is a vessel that is designed to operate underwater and is usually powered by an electric motor. A submarine is a military vessel that is capable of operating underwater for extended periods of time. A bathyscaphe is a type of submersible that is designed to explore the deep sea. Lastly, a diver propulsion vehicle is a small craft that is used by divers to move through the water more quickly and efficiently. Each of these words can be used to describe a different type of underwater craft, depending on the specific context.