Swimmer Delivery Vehicle

The SDV (Swimmer Delivery Vehicle) is a kind of torpedo that is designed to transport combat swimmers from a combat swimmer unit or naval Special Forces underwater, over long distances to and from maritime mission objectives on land or at sea. SDVs can carry their own onboard compressed air supply to extend the range of a swimmer's own air tank or rebreather equipment. The SDV can go as fast as 115 miles per hour. To reach such speeds, the vehicle needs to make use of supercavitation. A bubble of gas is generated around an object, reducing drag and making high speed underwater possible. It is developed by DARPA.