SEAL Delivery Vehicle
SEAL Delivery Vehicle Team Two launch an SDV from Los Angeles-class submarine USS Philadelphia
| |
Class overview | |
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Builders | The Columbia Group[2] |
Operators | United States Navy |
Succeeded by | Shallow Water Combat Submersible (planned)[1] |
In commission | Since 1983[1] |
General characteristics | |
Type | Submersible, diver propulsion vehicle |
Displacement | 17 tons (15.4 tonnes)[3] |
Length | 6.7 meters (22 ft)[4] |
Beam | 1.8 meters (5.9 ft)[3] |
Propulsion | |
Speed | |
Range | |
Endurance | 8[6] to 12 hours[7] |
Test depth | 6 meters (20 ft)[8] |
Complement | 6 (2 crew, 4 passengers)[4] |
Sensors and processing systems | Doppler GPS[5] |
Armament | SEAL team personal weapons, limpet mines[7] |
Notes | Specifications are given for Mark 8 SDV |
The SEAL Delivery Vehicle (SDV) is a crewed submersible and a type of swimmer delivery vehicle used to deliver United States Navy SEALs and their equipment for special operations missions. It is operated by SEAL Delivery Vehicle Teams.
The SDV, which has been in continuous service since 1983, 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 is generally deployed from the
The SDV was intended to be replaced with the Advanced SEAL Delivery System (ASDS), a larger, dry submersible that is often confused with the SDV. 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, while the ASDS is dry inside and equipped with a full life support and air conditioning system. The ASDS was canceled in 2009 due to cost overruns and the loss of the prototype in a fire.[10][11] The Navy currently plans to replace the SDV with the Shallow Water Combat Submersible (SWCS), which will be designated the Mark 11 SDV.[1] The SWCS was expected to enter service in 2019.
History
The SDV program dates back to
The same capability was adopted by the American Underwater Demolition Teams (UDTs) in 1947. The one-man submersible displayed little functional military potential. However, it substantiated and characterized the need for improved and expanded UDT capabilities.[5] After the war, development continued in a garage-shop fashion by various UDT units, and included various "Marks" such as the Mark V, VI, and VII. Intermediate numbers were assigned to some vehicles that never made it off the shop floor. All were of flooded design.[13]
The first SDV to be operationally deployed was the Mark VII, which entered service in June 1972 after being tested between 1967 and 1972.
The wet vehicle SDV program (officially named the Swimmer Delivery Vehicle, later re-designated the SEAL Delivery Vehicle after the Swimmer Delivery Vehicle Teams were renamed
Design
SDVs carry a pilot, co-pilot, and four person 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 is
SDVs are generally launched from a
An SDV can be launched from one platform and recovered by another.
Mark 8 SDV
The Mark 8 Mod 1 SDV is the only SDV officially in use by the US Navy and Royal Navy. It is an upgrade of the earlier Mark 8 Mod 0 SDV. The Mod 1 is quieter, faster, more efficient, and has a longer range than the Mod 0.
The Mark 8 Mod 1 SDV has an endurance of about eight to 12 hours,[7] giving it a range of 15 to 18 nmi (28 to 33 km) with a diving team or 36 nmi (67 km) without.[3] The main limiting factor on endurance is not batteries or breathing gas for the SEALs, but water temperature:[17] humans can only spend so much time in cold water, even with wetsuits, before their blood pressure drops and they become dehydrated from losing blood volume and body fluids, respectively.[6]
Mark 9 SDV
Despite being a development of the Mark 8 SDV, the Mark 9 is a very different vehicle, designed for attacking surface ships rather than deploying SEAL teams on clandestine operations. Indeed, the Mark 9 and Mark 8 share very few common parts.
The Mark 9 is designed to clandestinely approach enemy vessels while submerged, surface to fire torpedoes, and then escape unnoticed. As such, its design incorporates stealth characteristics, including a lower profile and sonar absorbing materials.[19] The Mark 9 SDV was intended to attack ships in shallow coastal waters that full-size submarines could not enter,[5] and to draw attention of an enemy fleet away from the Mark 9's parent submarine.[18] Though it proved very effective in exercises, the Mark 9 was retired starting in 1989 and was fully phased out of service by the mid-1990s due to manpower and budget constraints and because all of its capabilities save launching torpedoes were duplicated by the Mark 8.[5]
The pilot and navigator operate the vehicle from a prone position and lay side by side. The prone position gave the Mark 9 a low profile and enabled it to operate in very shallow water,[6] although SEALs reported that staying prone for the entire duration of an operation was uncomfortable.[18]
The Mark 9's sleek profile and independent
Operational history
The SDV is used primarily for inserting SEALs for covert operations or for placing mines on ships. It is also used for underwater mapping and terrain exploration, location and recovery of lost or downed objects, and reconnaissance missions.[20] It has been invaluable at deploying SEAL teams in clandestine missions, as it has enabled them to land on shores inaccessible to a larger submarine with a degree of stealth greater than that offered by small surface craft, helicopters, or other means.[14] In exercises, the SDV has been found to excel at anti-shipping attacks, being able to attack targets in heavily-guarded fleets or docked at military bases and then slip away undetected.[21] Additionally, it can carry larger limpet mines than those carried by a diver and has a much greater range than a diver, enabling attacks on larger and more distant enemy ships.[6] However, the SDV is not without its weaknesses, namely its range, reliability, and mobility. The SDV's short range, which is contingent on sea state, water temperature, payload, and other factors, sometimes hinders operations. In one example, the Navy wanted to use an SDV to get a closer look at a Soviet ship anchored in a Cuban harbor 18 miles (29 km) upriver from the Caribbean Sea. The SDV could not have made the round trip to the Soviet vessel from an American ship outside of Cuba's territorial waters, so the mission had to be called off.[6]
Mark 8 SDVs saw combat during the
In 2003, SEALs using SEAL Delivery Vehicles swam ashore along the Somali coastline and emplaced covert surveillance cameras. Known as cardinals, the cameras were designed to watch likely target locations for wanted terrorists as al-Qaeda and its affiliates began to regroup in the country, however the cameras only took one image a day and captured very little.[24]
In American service, the SDV is deployed with
The SDV suffered from reliability concerns early in its lifespan.
The main failure of the SDV is its poor mobility.
The Special Boat Service of the United Kingdom Special Forces operates three Mark 8 Mod 1 vehicles.[25][26]
Operators
- Navy SEALs
- SEAL Delivery Vehicle Team 1(SDVT-1)
- SEAL Delivery Vehicle Team 2(SDVT-2)
Gallery
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A Navy diver and special operator from SEAL Delivery Team 2 operate an SDV from the nuclear-powered guided-missile submarine USS Florida (SSGN-728)
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An SDV being loaded aboard Los Angeles-class attack submarine USS Dallas
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Mark 9 SDV "Little Bo Peep" armed with a LAM-5 mine
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A member of SEAL Delivery Vehicle Team Two (SDVT-2) prepares to launch a Mark 8 SDV from Los Angeles-class attack submarine USS Philadelphia
See also
References
- ^ ISSN 1059-1028. Retrieved 2018-09-04.
- ^ Delaney, Katy (July 10, 2013). "Dual Use Submersible Vehicle Wins Prestigious R&D 100 Award for Battelle, The Columbia Group, and Bluefin Robotics" (Press release). Battelle. Retrieved 20 September 2018 – via MarketWired.
- ^ a b c d e Jane's Fighting Ships. 2010.
- ^ Maxwell Air Force Base, Alabama: Air Command and Staff College. AU/ACSC/145/1998-04. Retrieved 7 September 2018.
- ^ a b c d e f g h i j k l m "SEAL Delivery Vehicles". National Navy UDT-SEAL Museum. Retrieved 4 September 2018.
- ^ ISBN 9781504047456.
- ^ a b c Davis, Eric (December 24, 2013). "US Navy SEALs: SDV1". Special Operations. Retrieved 4 September 2018.
- ^ Hooton, E. R. (December 1, 2005). "By sea & stealth: maritime special forces tend to arrive in hostile territory by sea and by stealth, but where once they would be delivered by rubber dinghies from a submarine now they are using Special Delivery Vehicles (SDV) and even midget submarines". Armada International. Retrieved September 4, 2018.
- Seapower.
- Honolulu Star Advertiser.
- ^ Polmar, Norman (16 December 2008). "Problems Persist for SEAL Mini-Subs". Military.com. Archived from the original on 22 January 2009. Retrieved 2008-12-16.
- ISBN 978-1-84868-065-4.
- ^ Commander, Naval Special Warfare Command
- ^ a b c Thompson, Kalee; Weinberger, Sharon; Pappalardo, Joe (1 August 2011). "Secrets of the Navy SEALs". Popular Mechanics. Retrieved 19 September 2018.
- ^ a b Pike, John. "SEAL Delivery Vehicle [SDV]". Global Security. Retrieved 4 September 2018.
- ^ a b c d Klose, John (July 2003). "SDV Units in Great Demand as Speed, Range Improve". Seapower. Archived from the original on 6 September 2018. Retrieved 5 September 2018.
- ^ ISBN 9781612510064.
- ^ a b c d Sutton, H.I. (21 August 2016). "SDV Mk9: US Navy SEAL's torpedo armed mini-sub". Covert Shores. Retrieved 20 September 2018.
- ISBN 9780671868536.
- ^ Army Command and General Staff College. 1999.
- ISBN 9780990915300.
- ISBN 978-1-84529-821-0.
- ISBN 978-1-47280-790-8.
- ^ Neville (2015), pp. 282–284.
- ^ Dorschner, Jim (27 May 2009). "Special Delivery". Jane's Defence Weekly. 46 (21): 28.
- ^ J. Valaik, Daniel; E. Hyde, Dale; F. Schrot, John; R. Thomas, John (November 1997). "Thermal Protection and Diver Performance in Special Operations Forces Combat Swimmers (Resting Diver Phase)" (PDF). Defense Technical Information Center. Naval Medical Research Institute. p. 100. Archived from the original (PDF) on 2022-07-21.