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Shallow Water Combat Submersible

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Class overview
BuildersTeledyne Brown Engineering[3]
OperatorsUnited States Navy
Royal Navy (planned)
Preceded bySEAL Delivery Vehicle
Cost$383 million (program cost)[1]
On order7 USN, 3 RN[4][5]
General characteristics
TypeSubmersible, diver propulsion vehicle
Displacement4.5 tonnes (5.0 short tons)[3]
Length6.8 meters (22 ft)[3]
Beam1.5 meters (4.9 ft)[3]
Draft1.5 meters (4.9 ft)[3]
PropulsionLithium-ion batteries powering electric motors
Speed6 kn (11 km/h)
Endurance12 hours[6]
Test depth>190 feet (58 m)[6]
Complement6 (2 crew, 4 passengers)[3]
Sensors and
processing systems
Inertial navigation system, high-frequency sonar for obstacle/mine avoidance and navigation, GPS
ArmamentSEAL team personal weapons, limpet mines

The Shallow Water Combat Submersible (SWCS) is a crewed submersible and a type of swimmer delivery vehicle that is planned to be used to deliver United States Navy SEALs and their equipment for special operations missions. It will replace the current Mark 8 SEAL Delivery Vehicle. The Navy planned to introduce the SWCS in 2018,[7] although "slippage in the development"[8] has delayed its introduction until 2019. In 2020, the U.S. Navy stated that it was undergoing sea trials and testing.[2][9] As of October 2018, two subs have been delivered to the Navy while another two were in production.[2] The SWCS will serve alongside the Dry Combat Submersible (DCS), a midget submarine with a dry interior being developed by Lockheed Martin as a replacement for the cancelled Advanced SEAL Delivery System (ASDS).[8]: 7 


The SWCS program was initiated in 2008, after the cancellation of the ASDS, the anticipated replacement for the SEAL Delivery Vehicle.[10] Teledyne Brown Engineering was awarded the $383 million contract to develop the SWCS in 2011, which provides for the construction of 10 submersibles and one training vessel, the first of which was supposed to enter service in 2018.[4] However, delays and cost overruns began as early as 2015, leading Congress to halve the funds available for the program in the FY2016 National Defense Authorization Act.[11] As of May 2018, the prototype boat had been built and was undergoing testing,[12][13] while introduction was pushed back to 2019.[2] By October, two subs had been delivered to the Navy.

In September 2018 the Defense Security Cooperation Agency notified Congress of the possible sale of 3 SWCSs to the United Kingdom for a total of $90 million.[5]


The SWCS is 12 inches (30 cm) longer and 6 inches (15 cm) taller than its predecessor, the Mark 8 SDV.[12] The SWCS will have a longer range and higher payload capacity than its predecessor.[14] As such, it will also be about 4,000 pounds (1.8 t) heavier than its predecessor.[12] Its hull is made from aluminum.[2] The SWCS will also have more advanced computer systems and better navigation,[12] with new systems including a "sensor mast" with an electro-optical periscope, wireless and wired communication between crew members, sonar detectors, and sonar-assisted automatic docking.[6] The computer bus and sensor mast are designed as modular systems so that individual sensors or systems can be swapped out as required by an individual mission and upgraded as desired.[6] Like its predecessor, the SWCS will carry six SEALs: a pilot, a co-pilot/navigator, and four passengers. The SWCS can be deployed from surface ships, land, and Dry Deck Shelters (DDS) on submarines,[15] although the third option is preferred for stealth reasons.[8][15]

Compared to the DCS it will serve alongside, the SWCS will be able to enter areas that the DCS cannot.[8]: 7  It will also be deployable from submarines, a capability that the DCS lacked as of 2015.[8]: 17 

The SWCS's larger dimensions will require expanding the DDS to accommodate it.[15] The Navy plans to lengthen the DDS by 50 inches (1.3 m) and triple its weight capacity.[13]

The prototype SWCS being tested in a pool


  1. ^ "Teledyne Awarded $383 Million Shallow Water Combat Submersible Contract". Defense-aerospace.com. 11 July 2011. Retrieved 6 September 2018.
  2. ^ a b c d e f Burgess, Richard (October 2018). "New Seahorses For The Seals". Seapower.
  3. ^ a b c d e f Sutton, H.I. (19 May 2017). "SWCS". Covert Shores. Retrieved 20 September 2018.
  4. ^ a b "Teledyne Leads As U.S. Navy Seals Seek Next-Generation Mini-Subs" (PDF). The Silent Sentinel. Bloomberg Government. September 29, 2011. Retrieved 20 September 2018.
  5. ^ a b "United Kingdom – SEAL Delivery Vehicle (SDV) MK 11 Shallow Water Combat Submersibles (SWCS)". Defense Security Cooperation Agency. 20 September 2018. Retrieved 24 September 2018.
  6. ^ a b c d Page, Lewis (10 April 2009). "New Navy SEAL minisub's IT-system specs released". The Register. Retrieved 6 September 2018.
  7. ^ Szymanski, Tim (April 11, 2018). Statement of Rear Admiral Tim Szymanski, U.S. Navy Commander Naval Special Warfare Command before the Senate Armed Services Committee Subcommittee on Emerging Threats and Capabilities (PDF) (Speech). Washington, D.C. Retrieved September 16, 2018.
  8. ^ a b c d e McRaven, William (March 14, 2015). Hearing on National Defense Authorization Act for Fiscal Year 2015 and Oversight of Previously Authorized Programs Before the Committee on Armed Services, House of Representatives, One Hundred Thirteenth Congress, Second Session (PDF). Subcommittee on Intelligence, Emerging Threats and Capabilities Hearing on Fiscal Year 2015 National Defense Authorization Budget Request from the U.S. Special Operations Command and Posture of the U.S. Special Operations Forces. Washington, DC: Government Printing Office. Retrieved January 23, 2019.
  9. ^ Ong, Peter (7 June 2020). "USSOCOM Reveals Dry Combat Submersible Entering Service Soon". Naval News. Retrieved 23 June 2023.
  10. ^ Olson, Eric (June 18, 2009). Department of Defense Authorization for Appropriations for Fiscal Year 2010, S. Hrg. 111-100, PT.5 (PDF). Senate Armed Services Committee, 111th Congress. Washington, DC: Government Printing Office. Retrieved January 23, 2019.
  11. ^ National Defense Authorization Act for Fiscal Year 2016 (PDF) (129 STAT. 726 PUBLIC LAW 114–92, Section 202). November 25, 2015. p. 774.
  12. ^ a b c d Dollof, Kate (May 2018). PEO Portfolio Review (PDF). Special Operations Forces Industry Conference. Tampa, FL.
  13. ^ a b Lehnardt, Keith (May 2018). Maritime (PDF). Special Operations Forces Industry Conference. Tampa, FL.
  14. ^ Tadjdeh, Yasmin (June 26, 2018). "New Maritime Technology for Navy SEALs on the Way". National Defense. Retrieved January 15, 2019.
  15. ^ a b c O'Rourke, Ronald (August 1, 2018). Navy Irregular Warfare and Counterterrorism Operations: Background and Issues for Congress (PDF) (Report). Congressional Research Service. RS22373. Retrieved September 16, 2018.