A Submarine, also known as a Submersible, is a type of vessel that is designed to operate beneath the surface of the ocean. These vessels are generally designed to transport either goods or passengers from one area to another, as well as perform research, exploration and survey missions. Submarines are built to withstand depths that regular surface vessels cannot reach, allowing for research to be conducted quickly in the deep. Submarines can be equipped with a variety of technological and scientific apparatus to allow for research and navigation to be conducted more efficiently. These vessels are powered by diesel-electric propulsion systems, allowing for more efficient use of the boat's inherent fuel reserves.