20 February 2020

Minisubmarines for the undetected insertion and extraction of naval forces

Daniel Ilie

The “frogmen” from the US Navy Seals, naval forces operators for the special operations, have used, since the end of the Cold War, the so called Gator Class SEAL Delivery Vehicle- SD, SDV Mk.8 Mod 0, for the undetected insertion and extraction during specific missions.

Image source: Mediafax

I was writing in one of my first “columnist” attempts about the Naval Special Operations Forces, the so-called- quiet professionals- organized, equipped and trained to execute specific SEa Air Land-SEAL missions (special research, direct actions, military and unconventional assistance, as well as their complementary missions).m

Among others, I was saying that such capabilities are composed of those divers specially equipped with scuba closed circuit underwater breathing apparatus, rebreathers, undetectable frogmen who suddenly emerge (the element of surprise) wearing black wetsuits, wearing flippers, and practically dropping water and fear, full armed with individual weaponry and state of the art vision googles and scopes (including night vision) ready to conduct specific missions and tasks on sea, air, or land.

I was then talking about some of the procedures these really well trained and instructed operators use to insert, undetectably, in the objective they are about to execute such mission in. I am talking about  those who infiltrate through air, from helicopters (including Navy’s), using Fast Rope Insertion Extraction System ( FRIES) techniques to board ships, or floating platforms, the so-called RHIBs (Rigid Hull Inflatable Boat), but also about underwater insertion through diving and underwater swimming. In the latter case, usually, the submarine insertion is being made from a floating construction (with or without self propulsion), such as a platform, ship or boat, but also from ships board which have mixed navigation possibility, surface and immersion, like submarines or submersibles.

It seems that among the first attempts to use underwater insertion, undetectably, starting from military submarines boards in submersion, conducted before the start of World War II, there are also the actions of Soviet military divers who, during their military exercises, they got off a Shchuka ShCh- 112 submarine belonging to the Russian Fleet of Pacific, through a torpedo tube, they swam under the water to the established objective, simulating, then, the execution of sabotage actions.

British and US NSOF like US Navy SEALS and the UK Special Boat Service (SBS) have used, since the 80’s, and are still using, for the undetected insertion and extraction to/from the target objective possibly on a ship, littoral or land, miles away from the starting point, the so called SEAL Delivery Vehicle- SDV. These are, in fact, some minisubmarines on board of submarines big enough to carry them (they have a special hangar on the dry deck shelter), usually with nuclear propulsion, where there can also carry other operational teams or detachments of NSOF ready to execute specific mission within the special operations.

Although these are somehow known in the SOF experts’ community, on these mini-subs there is not that much information. According to H.I. Sutton, defence analyst and important global expert in underwater war and submarines technology, contributor to Forbs and Jane’s, admin to “Covert Shores” and author of “Covert Shores: The story of naval” and “World Submarines: Covert Shores Recognition Guide”, US Navy SEALS have relied on the transport vehicle/Gator Class SEAL Delivery (SDV Mk.8 Mod 0, also written MK. VIII Mod 0), since the end of the Cold War.

In the endowment of these naval special operations forces (initially of the Underwater Demolition Teams – UDT and, then, SEAL team) have also been in included the Mk. 7 models (with 4 operators on board), but also Mk. 9 (with two operators on board, conceived for research and attack missions and which can be equipped with two modified torpedos).

The MK.8 can transport 6-8 combat swimmers and their gear from a submerged “host” submarine, through small depth waters, to a distance wherefrom these fighters can swim to the designated target objective and where is about to execute the mission.  After the mission has been successfully completed, the fighters will return to the submarine "parked" on the bottom of the water, will embark and try to return to the submarine "host", as appropriate and depending on the remaining autonomy of the battery pack. Following a forced analogy, it is a case somewhat similar to the potential use by the Special Operations Forces of tactical insertion platform on wheels - the electric scooter - that I wrote in this article.

This fight submersible appears to be the largest, robust and fastest of other similar submarines in the armies of other countries of the world, and can mainly be housed only by attack submarines from the US Naval Forces and UK Naval Forces. By comparison, the Soviet miniature submarine Triton-2 was never integrated on such a "host" submarine, Sutton argues. Mini submarines built by countries like France and Italy, much smaller in size, were designed and built for different missions.

From the photo posted on the Covert Shores Website it turns out that Mk.8 Mod 0 is a "wet" submarine, deliberately floodable (the crew is practically staying in the water), propelled by a propeller driven by an electric motor powered by a set of batteries. It can transport silently and undetectable, with a maximum speed of about 6 knots, up to 8 NSOF operators equipped with combat (neoprene suits, flippers and individual armament), in the seated position and with the breathing apparatus connected at the oxygen source of the submersible (two facing the front of the vehicle - the pilot and the navigator, and up to 6 passengers behind them, facing the rear of the transport/delivery vehicle).

The mini submarine hull is made of fiberglass, has no windows and is divided into 5 main compartments, being a modular construction. At the proof (the front of the submersible) is the compartment (container) of the instrument panel, and attached to it immediately backwards is the pilot and navigator’s compartment. The compartment is provided with a side sliding hatch required for operators’ access.

To the stern (rear of the submarine) is the passenger compartment (4 to 6), which is also provided with a side sliding access hatch, followed by the engine compartment. In the middle, between the two compartments intended for the transport of the SEAL team members, there is the compartment with breathing tubes. At the stern are the propeller, as well as the vertical rudder and hydroplanes required for displacement control.

Finally, the mini-submarine also has some additional compartments needed to store magnetic mines that can be attached to the bodies of ships to damage/destroy them by explosion or to dock unmanned underwater vehicles - Mk18 Mod 1 Swordfish Unmanned Underwater Vehicles - intended for the fight against marine mines.

According to another photo published on the website TheAviationist, the mini-submarine has a length of over 7 meters, is equipped with sonar for detecting and avoiding obstacles to the forward movement, global positioning system (GPS), communication system, as well as systems control and dual display (displays). The vehicle was designed in a modular system for easier maintenance work.

Such minisubmarines can be housed and launched from a hangar attached to the deck of a host submarine, but also from surface vessels or by helicopter and can operate in shallow waters, around 30 meters, being very useful in transport, the insertion and relatively rapid extraction of NSOF in one or of a hostile area controlled by the enemy, without being detected by the radar and thus ensuring its capture, but also increasing the survival chances of its own forces during the retreat. These underwater platforms can also be used for research missions, electronic warfare, port security or naval mine fighting.

A very brief example of tactics, techniques and procedures used by US Navy SEALs teams to INSERT such an underwater transport /delivery vehicle to the target and to execute the mission to it can be seen in this video.

Although from photo and video images the operation of such a "wet" submarine may seem relatively easy, the specialists claim that training, operation and maintenance of this type of mini-submarine are expensive and difficult processes that, initially, not even SEAL teams did not allow them, their operation requiring special skills and training that not everyone has.

As I wrote in the past, even Islamic Republic of Iran Navy (IRIN), in particular the Special Boat Service (SBS) unit, are capable of secretly infiltrating minisubmarines within the Iranian Naval Forces.

These "wet" scuba transport /delivery vehicles are locally manufactured by the Iranian defence industry (a version of Al-Sabehat 15 SDV). According to H.I. Sutton, this type of mini-submarine was not designed and manufactured to be launched aboard a host submarine, but is normally launched from an amphibious battleship and is used in beach research missions prior to the start of amphibious landing operations. It can, however, also carry magnetic marine mines for ship attack.

The "wet" transport /delivery swimmer vehicle SEAL type SDV Mk.8 Mod 0, however, is to be replaced by a new type of combat submarine with a longer range, this time dry (its interior is not it will be deliberately flooded with water, and SEAL teams will travel in the dry environment), called Mk. 11 Shallow Water Combat Submersible - SWCS. For the purchase of this type of mini-submarine, the US Special Operations Command has allocated by contract $ 178 million.

There are about 10 pieces of such combat submersibles that would be ready by 2023 under the US Department of Defence endowment program called "SOCOM Dry Combat Submersible Medium - DCSM". Such a mini-submarine weighs around 30 tonnes, will be powered by an electric motor powered by a set of LiFT (Lithium-ion Fault Tolerant) batteries that have proven their reliability and resistance to underwater conditions and extreme environments and can be launched from surface ships.

Also, the UK plans to buy 3 combat submersibles in shallow water type Mk. 11 Shallow Water Combat Submersible for an estimated total of $ 90 million. These 3 combat submarines will replace the 3 SEAL SDV Mk.8 Mod 0 transport /delivery vehicles already equipped with the UK Special Boat Service.

Most likely, the ROU FNOS can only dream, for now, of such underwater insertion platforms, transportable on board of a submarine large enough to be able to host them on its deck. This is also because the only submarine in the Romanian Naval Forces, the Dolphin, has been moored for more than two decades, not being operational due to the lack of batteries and, according to the specialists, with no chance of ever being revitalized. Probably not even the option of using a surface ship in the military fleet to transport and launch such underwater vehicles would be a feasible solution.

In 2018, one of the former ministers who led the Ministry of National Defence in recent years said that they were thinking of a very ambitious program to equip the naval forces with 3 submarines. It was an endowment program called "Submarine against surface and underwater threats". Now, however, we do not see it among the 8 major programs in the “The Army Endowment Plan 2017-2026”.

Translated by Andreea Soare