Semi-submersible naval vessel

A semi-submersible naval vessel is a special kind of ship that can partially submerge itself, or move underwater. It looks like a big floating platform with a special kind of hull that is made to be able to sink. The semi-submersible ship can move either on the surface or underwater, depending on what the mission requires. The ship is mainly used as an intelligence gathering and surveillance platform, as it can hide underwater when necessary and observe while not being seen. It is also used sometimes in underwater missions, such as search and recovery operations.