A Mark 8 SEAL Delivery Vehicle (SDV) is piloted by two Navy SEALs of Naval Special Warfare Command's SEAL Team 2. The SDV is a 22-foot long jet black submersible all-electric vehicle powered by rechargeable siver-zinc batteries. The torpedo shaped underwater SCV has a computerized navigation system and is equipped with an intercom system allowing the crew and passengers to talk underwater. The pilot controls its direction with a ballast and trim system, along with a manual control stick to move rudders, elevators and bow planes much