SEAL Delivery Vehicle
Encyclopedia
The SEAL Delivery Vehicle or (SDV) is a manned submersible
and a type of Swimmer Delivery Vehicle
used to deliver United States Navy SEALs
and their equipment for special operations
missions.
SDVs carry a pilot, co-pilot, and combat swimmer team and their equipment to and from maritime mission objectives on land or at sea. The pilot and co-pilot are often a part of the fighting team. The SDV has compressed air to extend the range of a swimmer's own air tank
or rebreather
.
The SDV is used primarily for covert or clandestine missions to denied access areas (either held by hostile forces or where military activity would draw notice and objection).
It should not be confused with the larger, dry submersible called the Advanced SEAL Delivery System
(ASDS). The SDV is flooded
, and the swimmers ride exposed to the water, breathing from the vehicle's compressed air supply or using their own SCUBA gear. (The ASDS is dry inside, with a full life support and air conditioning system.)
The SDV is lithium-ion battery powered and equipped with propulsion, navigation, communication, and life-support equipment. The Mk 8 Mod 1 SDV can deliver several fully equipped SEALs to the mission area, be "parked" or loiter in the area, retrieve the SEALs, and return home.
The Mark 8 Mod 1 SDV is currently the only SDV employed by US military. Other operational vehicles included the now retired MK 6, MK 7, and the Mk 11. The Special Boat Service
of the British
Royal Marines
operates three Mk8 Mod 1 vehicles.
SDVs are generally launched from a Dry Deck Shelter
on the back of a submarine
, or from amphibious carriers (surface craft) equipped to launch and recover the SDV. It can also be airdrop
ped (unmanned) into an operational area from a C-130 Hercules
.
, when various sleds and vehicles like the Sleeping Beauty
were developed for use by the Underwater Demolition Team
s. After the war development continued in a garage-shop fashion by various UDT units, and included various "Marks" as the MK V, VI, VII, and XII. Intermediate numbers were assigned to some vehicles that never made it off the shop floor. All were of flooded design.
The wet vehicle SDV program (officially named the Swimmer Delivery Vehicle, sometimes erroneously designated as the SEAL Delivery Vehicle after the Swimmer Delivery Vehicle Teams were renamed SEAL Delivery Vehicle Teams) currently centers on the MK VIII MOD 1, was first established in 1975 for use among UDT/SEAL teams. The early MK8 MOD 0 SDVs had a PRC104 UHF ultra high frequency
radio for use underway. The newer model MK8 MOD1 has a dual sliding canopy and quick release hatch.
Submersible
A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...
and a type of Swimmer Delivery Vehicle
Swimmer Delivery Vehicle
Swimmer Delivery Vehicles are midget submersibles designed to transport frogmen from a combat swimmer unit or naval Special Forces underwater, over long distances. SDVs carry a pilot, co-pilot, and combat swimmer team and their equipment, to and from maritime mission objectives on land or at sea...
used to deliver United States Navy SEALs
United States Navy SEALs
The United States Navy's Sea, Air and Land Teams, commonly known as Navy SEALs, are the U.S. Navy's principal special operations force and a part of the Naval Special Warfare Command as well as the maritime component of the United States Special Operations Command.The acronym is derived from their...
and their equipment for special operations
Special operations
Special operations are military operations that are considered "special" .Special operations are typically performed independently or in conjunction with conventional military operations. The primary goal is to achieve a political or military objective where a conventional force requirement does...
missions.
SDVs carry a pilot, co-pilot, and combat swimmer team and their equipment to and from maritime mission objectives on land or at sea. The pilot and co-pilot are often a part of the fighting team. The SDV has compressed air to extend the range of a swimmer's own air tank
Diving cylinder
A diving cylinder, scuba tank or diving tank is a gas cylinder used to store and transport high pressure breathing gas as a component of a scuba set. It provides gas to the scuba diver through the demand valve of a diving regulator....
or rebreather
Rebreather
A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycled exhaled gas. This recycling reduces the volume of breathing gas used, making a rebreather lighter and more compact than an open-circuit breathing set for the same duration in environments where...
.
The SDV is used primarily for covert or clandestine missions to denied access areas (either held by hostile forces or where military activity would draw notice and objection).
It should not be confused with the larger, dry submersible called the Advanced SEAL Delivery System
Advanced SEAL Delivery System
Advanced SEAL Delivery System was a midget submarine operated by the United States Navy and United States Special Operations Command that is designed to provide stealthy submerged transportation for special operations forces from the decks of nuclear submarines for primary use as an insertion...
(ASDS). The SDV is flooded
Wet sub
A wet sub is a type of underwater vehicle that does not provide a dry environment for its occupants. Usually, wet suited scuba divers will ride upon the device , although it can be designed to fully enclose its occupant to provide lower drag...
, and the swimmers ride exposed to the water, breathing from the vehicle's compressed air supply or using their own SCUBA gear. (The ASDS is dry inside, with a full life support and air conditioning system.)
The SDV is lithium-ion battery powered and equipped with propulsion, navigation, communication, and life-support equipment. The Mk 8 Mod 1 SDV can deliver several fully equipped SEALs to the mission area, be "parked" or loiter in the area, retrieve the SEALs, and return home.
The Mark 8 Mod 1 SDV is currently the only SDV employed by US military. Other operational vehicles included the now retired MK 6, MK 7, and the Mk 11. The Special Boat Service
Special Boat Service
The Special Boat Service is the special forces unit of the British Royal Navy. Together with the Special Air Service, Special Reconnaissance Regiment and the Special Forces Support Group they form the United Kingdom Special Forces and come under joint control of the same Director Special...
of the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
Royal Marines
Royal Marines
The Corps of Her Majesty's Royal Marines, commonly just referred to as the Royal Marines , are the marine corps and amphibious infantry of the United Kingdom and, along with the Royal Navy and Royal Fleet Auxiliary, form the Naval Service...
operates three Mk8 Mod 1 vehicles.
SDVs are generally launched from a Dry Deck Shelter
Dry Deck Shelter
A Dry Deck Shelter is a removable module that can be attached to a submarine to allow divers easy exit and entrance while the boat is submerged...
on the back of a submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
, or from amphibious carriers (surface craft) equipped to launch and recover the SDV. It can also be airdrop
Airdrop
An airdrop is a type of airlift, developed during World War II to resupply otherwise inaccessible troops, who themselves may have been airborne forces. In some cases, it is used to refer to the airborne assault itself. Early airdrops were conducted by dropping or pushing padded bundles from...
ped (unmanned) into an operational area from a C-130 Hercules
C-130 Hercules
The Lockheed C-130 Hercules is a four-engine turboprop military transport aircraft designed and built originally by Lockheed, now Lockheed Martin. Capable of using unprepared runways for takeoffs and landings, the C-130 was originally designed as a troop, medical evacuation, and cargo transport...
.
History
The SDV program dates back to World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, when various sleds and vehicles like the Sleeping Beauty
Sleeping Beauty (canoe)
The Motorised Submersible Canoe , nicknamed Sleeping Beauty, was built by British Special Operations Executive during World War II as an underwater vehicle for a single frogman to perform clandestine reconnaissance or attacks against enemy vessels.-Design:The MSC was designed by Major Hugh Quentin...
were developed for use by the Underwater Demolition Team
Underwater Demolition Team
The Underwater Demolition Teams were an elite special-purpose force established by the United States Navy during World War II. They also served during the Korean War and the Vietnam War...
s. After the war development continued in a garage-shop fashion by various UDT units, and included various "Marks" as the MK V, VI, VII, and XII. Intermediate numbers were assigned to some vehicles that never made it off the shop floor. All were of flooded design.
The wet vehicle SDV program (officially named the Swimmer Delivery Vehicle, sometimes erroneously designated as the SEAL Delivery Vehicle after the Swimmer Delivery Vehicle Teams were renamed SEAL Delivery Vehicle Teams) currently centers on the MK VIII MOD 1, was first established in 1975 for use among UDT/SEAL teams. The early MK8 MOD 0 SDVs had a PRC104 UHF ultra high frequency
Ultra high frequency
Ultra-High Frequency designates the ITU Radio frequency range of electromagnetic waves between 300 MHz and 3 GHz , also known as the decimetre band or decimetre wave as the wavelengths range from one to ten decimetres...
radio for use underway. The newer model MK8 MOD1 has a dual sliding canopy and quick release hatch.