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. [1] The watercraft is classified as medium-sized or small vessel. [2] This type of submarine differs from other underwater personal transport devices by the fact that it has a hull around it and it is not a "bare bones" design.
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(s) to reduce drag. An enclosed vehicle may also provide a dry viewing chamber for the occupant(s). 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. [3]
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. [4] 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. [5]
The Motorised Submersible Canoe, developed by the British Special Operations Executive during World War II, is another example.
A wet sub is attractive to the amateur or small commercial builder since many of the problems associated with a dry sub are avoided as only the propulsion and power systems need to be waterproof and life support is much less of an issue than it is with a sealed occupant chamber. Complete submarines of this type are also available commercially.
Wet sub designs are often used for human-powered submarines because they are smaller and lighter than dry submarines. [6] An example is the pedal-operated wet-sub called "the Scubster", which is powered by a twin propeller connected to the pedal belt. [7]
Every two years, a human-powered submarine race takes place at the Naval Surface Warfare Center in Bethesda, Maryland. [8]
Military wetsubs
Commercial wetsubs
Custom wetsubs
A frogman is someone who is trained in scuba diving or swimming underwater in a tactical capacity that includes military, and in some European countries, police work. Such personnel are also known by the more formal names of combat diver, combatant diver, or combat swimmer. The word frogman first arose in the stage name the "Fearless Frogman" of Paul Boyton in the 1870s and later was claimed by John Spence, an enlisted member of the U.S. Navy and member of the OSS Maritime Unit, to have been applied to him while he was training in a green waterproof suit.
A dry deck shelter (DDS) is a removable module that can be attached to a submarine to allow divers easy exit and entrance while the boat is submerged. The host submarine must be specially modified to accommodate the DDS, with the appropriate mating hatch configuration, electrical connections, and piping for ventilation, divers' air, and draining water. The DDS can be used to deploy a SEAL Delivery Vehicle submersible, Navy divers, or Combat Rubber Raiding Craft (CRRC).
A submersible is an underwater vehicle which needs to be transported and supported by a larger watercraft or platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent operation at sea.
A diver propulsion vehicle (DPV), also known as an underwater propulsion vehicle, sea scooter, underwater scooter, or swimmer delivery vehicle (SDV) by armed forces, is an item of diving equipment used by scuba divers to increase range underwater. Range is restricted by the amount of breathing gas that can be carried, the rate at which that breathing gas is consumed, and the battery power of the DPV. Time limits imposed on the diver by decompression requirements may also limit safe range in practice. DPVs have recreational, scientific and military applications.
A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to six or nine, with little or no on-board living accommodation. They normally work with mother ships, from which they are launched and recovered and which provide living accommodation for the crew and support staff.
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 United States Naval Special Warfare Command (USNSWC), also known as NAVSPECWARCOM and WARCOM, is the naval component of United States Special Operations Command, the unified command that oversees and conducts the nation's special operations and missions.
Human torpedoes or manned torpedoes are a type of diver propulsion vehicle on which the diver rides, generally in a seated position behind a fairing. They were used as secret naval weapons in World War II. The basic concept is still in use.
A diving chamber is a vessel for human occupation, which may have an entrance that can be sealed to hold an internal pressure significantly higher than ambient pressure, a pressurised gas system to control the internal pressure, and a supply of breathing gas for the occupants.
The Advanced SEAL Delivery System (ASDS) was a midget submarine operated by the United States Navy and United States Special Operations Command. It provided stealthy submerged transportation for United States Navy SEALs from the decks of nuclear submarines for use as an insertion platform for covert and clandestine special operations missions. The ASDS was canceled in 2009 due to cost overruns and reliability issues, after the prototype was destroyed in a fire in 2008. As of 2019, the Navy plans to replace the ASDS with the Dry Combat Submersible, a similar midget submarine being developed by Lockheed Martin.
The National Navy UDT-SEAL Museum, also known as the Navy SEAL Museum, is located in St. Lucie County, just outside Fort Pierce, Florida. It houses exhibits to inform and educate on the role of Navy Underwater Demolition Teams (UDT) and Sea, Air, Land (SEAL) teams. The museum also preserves the history of the SEALs.
Naval Special Warfare Group 3 (NSWG-3), based at the Naval Amphibious Base Coronado in California, was one of six constituent formations of the United States Naval Special Warfare Command. Until 2008, NSWG-3 was composed of two SEAL Delivery Vehicle Teams: SDVT-1 in Pearl Harbor and SDVT-2 in Little Creek. In 2008, SDVT-2 was disestablished and merged into SDVT-1, which was then now headquartered in Pearl Harbor and operated detachments in Pearl Harbor and Little Creek. SDV Teams are SEAL teams with an added underwater delivery capability. SDVT-2 was reactivated on 8 March 2019. NSWG-3 was deactivated alongside NSWG-10 in August 2021 and replaced by Naval Special Warfare Group 8 which took in all units previously under NSWG-3 and NSWG-10.
Operation Thunderhead was a highly classified combat mission conducted by U.S. Navy SEAL Team One and Underwater Demolition Team 11 (UDT-11) in 1972. The mission was conducted off the coast of North Vietnam during the Vietnam War to rescue two U.S. airmen said to be escaping from a prisoner of war prison in Hanoi. The prisoners, including Air Force Colonel John A. Dramesi were planning to steal a boat and travel down the Red River to the Gulf of Tonkin.
CosMoS CE2F were a series of swimmer delivery vehicles (SDV) built by M/s Cos.Mo.S Spa. which was based in Livorno, Italy.
A semi-submersible naval vessel is a hybrid warship, that combines the properties of a surface ship and submarine by using water ballast to partially immerse and minimize its above-waterline profile, thereby improving its stealth characteristics when in hostile waters. The USS Monitor was an antecedent to such craft with its low-profile deck and gun turret. Russian and North Korean semi-submersible naval vessels evolved from torpedo boats and special forces boats that could partially submerge to perform their missions. The US Navy SEALs use such vessels for clandestine special forces actions. Efforts to embody advantageous surface-ship characteristics into submarines have not been widely adopted.
The following outline is provided as an overview of and topical guide to underwater diving:
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, although "slippage in the development" has delayed its introduction until 2019. In 2020, the U.S. Navy stated that it was undergoing sea trials and testing. As of October 2018, two subs have been delivered to the Navy while another two were in production. 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).
The Dry Combat Submersible (DCS) is a midget submarine delivered to USSOCOM by Lockheed Martin. Lockheed Martin were nominated as the prime contractor with Submergence Group as the sub contractor. DCS is designed for use by the United States Navy SEALs for insertion on special operations missions. It will replace the canceled Advanced SEAL Delivery System and will serve alongside the Shallow Water Combat Submersible.