page_title: Wet sub
section_title: Military use
hierarchical_section_title: Wet sub / Military use
caption_attribution_description: English: Atlantic Ocean (May 5, 2005) - Members of SEAL Delivery Vehicle Team Two (SDVT-2) prepare to launch one of the team's SEAL Delivery Vehicles (SDV) from the back of the Los Angeles-class attack submarine USS Philadelphia (SSN 690) on a training exercise. The SDVs are used to carry Navy SEALs from a submerged submarine to enemy targets while staying underwater and undetected. SDVT-2 is stationed at Naval Amphibious Base Little Creek, Va., and conducts operations throughout the Atlantic, Southern, and European command areas of responsibility. U.S. Navy photo by Chief Photographer's Mate Andrew McKaskle (RELEASED)
context_page_description: A wet sub is a type of underwater vehicle, either a submarine or a submersible, that does not provide a dry environment for its occupants. It is also described as an underwater vehicle where occupants are exposed to ambient environment during operations. The watercraft is classified as medium-sized or small vessel.
  Usually, scuba divers ride outside the device as one would ride a motorcycle or in a semi-enclosed opening like a kayak or bobsled, although it can be designed to fully enclose its occupant to reduce drag. An enclosed vehicle may also provide a dry viewing chamber for the occupant. The sub is generally propelled by an electric motor and is battery powered. The depth and endurance is typically limited by the requirements of the divers, particularly water temperature and breathable air.
context_section_description: Wet subs have been used to transport and deploy special operations forces in waters too shallow for an ordinary submarine, lay mines (particularly for attaching limpet mines directly to a ship), firing torpedoes, or gathering intelligence in harbors. They have also been used to plant listening and recording devices on undersea cables in Operation Ivy Bells.  For military use, the operator will sometimes use a rebreather device so as not to leave a trail of bubbles. Military wet subs are deployed from a larger submarine or from a surface ship. The SEAL Delivery Vehicle (SDV) used by the United States Navy SEALs and British Special Boat Service is an example that is in use today. The SDV is used to insert Navy SEALs in shallow coastal waters or attack surface ships 
  The Motorised Submersible Canoe, developed by the British Special Operations Executive during World War II, is another example.
caption: SEAL Delivery Vehicle Team Two launch a wet sub from Los Angeles-class submarine USS Philadelphia
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