Dry deck shelter

During World War II, the United States Navy used submarines for the first time to deliver combat swimmers to the enemy shore for secret special operations. Diesel-electric submarines of that time had limited opportunities for entry / exit of combat swimmers due to the lack of capacious airlock chambers. These capabilities have been extended to the submarine USS Greybek (SS 574). On the submarine operated from 1969 to 1983, two airlock chambers were installed. On January 16, 1982, 5 US Navy divers died due to decompression sickness as a result of too rapid pressure release in the lock chamber. Further investigation revealed the need to develop specialized tools, procedures and training for deep-sea diving systems ^[1] .

The concept of a removable dock camera with the ability to transport vehicles MTR originated in the 1970s. The first dock camera was developed and manufactured by the Electric Boat Division of General Dynamics Corporation for the US Navy (simultaneously with the creation of the SDV) as part of a program for the development and manufacture of submarine fleet delivery units ^[2] . In 1982, the production of the DDS-01S module was completed. 01 is a sequence number, S is an index indicating which way the hangar gate opens; S - on the right side of the boat (from the English. S tarboard side )) index P says that the gate opens to the left side ( English P ort side ). In total, the fleet received six such modules. From 1987 to 1991, five more modules with indices DDS-02P, −03P, −04S, −05S, and −06P were produced at the Newport News Shipbuilding shipyard ^[3] . The possibility of opening the hangar gate in different directions due to the need to ensure the work of two near the installed modules ^[4] .

The DDS module has a maximum diameter of about 2.74 meters (9 feet), a length of about 11.6 meters (38 feet) and a displacement of about 30 tons ^{[approx. 1]} . The module consists of three hermetic compartments made of steel HY-80. The front compartment of the spherical shape is a decompression chamber. The middle compartment also has a spherical shape and is designed to interconnect the DDS compartments and the gateway adapter on the submarine hull. The third compartment is a hangar and is a cylinder with elliptical bottoms. In the front bottom is the gateway adapter for communication with the central compartment, and the aft bottom is also the doors opening to the side. To improve streamlining, the module is closed with a removable fiberglass fairing ^[1] . Inside the module, as well as on a submarine, atmospheric pressure is maintained ^[4] . The module is designed to operate to a depth of about 40 meters (130 feet) ^[1] .

The hangar is designed to transport one SDV vehicle ^[1] or can accommodate up to 20 combat swimmers and four ^[5] CRRC inflatable rubber boats ^[1] .

DDS modules can be transported on ships, trucks or C-5 Galaxy aircraft. Each module for transportation is equipped with a specially designed platform ( English truck ). The operations of unloading the module, installing it on a submarine, the necessary testing procedures take from one to three days ^[1] . The operation itself to install DDS on a submarine takes about 12 hours ^{[4] [3]} .

Two modules can be installed on board former strategic missile carriers, multi-purpose submarines can be equipped with only one module. To install the module, it is necessary to re-equip the submarine, which consists in installing the hatch gateway in the submarine hull, equipment for supplying the module with electrical energy, valves and pipes for air supply and water pumping ^[1] . On the upper deck of the submarine, special foundations are welded onto which the container is installed ^[5] . With the module installed, the submarine retains almost all of its characteristics (the maximum full submerged speed drops slightly) and retains the possibility of using weapons and electronic weapons ^{[3] [5]} . Initially, the equipment for the installation of a single module received USS Jimmy Carter (SSN-23) of the Sivulf type and all Virginia- class submarines ^[4] .

Equipment installed on Los Angeles-type boats, in addition to DDS modules, allows them to carry DSRV deep-sea rescue vehicles (the English D eep S ubmergence R escue V ehicle ) ^[6] . On some submarines, gateway devices provide the installation of both DDS modules and mini-submarines ASDS ( English A dvanced S EAL D elivery S ystem ). Such capabilities are possessed by converted former SSBNs of the Ohio type ^[7] , USS Jimmy Carter ^{[8] [9]} and the Virginia-type submarines ^{[10] [9] [11]} .

Typical is the use of DDS for two types of missions of special forces. These are the missions for the delivery of the SDV swimmers' submarine vehicle to the place of its launch ( eng. SDV missions ) and the mission for the mass delivery of swimmers to the landing site ( eng. M ass S wimmer L ock- O ut - MSLO ). In the first case, the module is used for transportation in the hangar of an SDV underwater vehicle (types Mark 8 mod 0, Mark 8 mod 1 and Mark 9) ^[1] . SDV is a vehicle for the delivery of swimmers of the so-called “wet” type. SDV mini-submarine is not sealed and swimmers are in it in diving equipment and use their own breathing apparatus. The capacity of an SDV is 8 people, of which one is an operator ^[12] . After the boat leaves the area where the special operation takes place, the hangar is flooded and pressure is balanced with the outboard. Support team divers open the outer door-gate and install special rail guides. Along the guides, a platform with an SDV installed on it extends and minisubmarines are launched. The divers who provided the SDV exit may return to the submarine or remain outside while awaiting the return of the SDV. When an SDV is returned, its operator will detect the submarine using an active sonar installed on board the vehicle. With the help of the divers, the SDV support team is fixed on its platform and with winches along the guides is dragged into the hangar, after which the hangar doors are closed ^[1] . The number of support divers is not specified, but based on data from some sources, the minimum SEAL mission team includes 14 sailors and petty officers, and two officers ^{[13] [approx. 2]} .

Missions for the mass landing of combat swimmers can be carried out both in the submarine and in the surface position of the submarine. As a rule, landing using CRRC inflatable rubber boats ( Eng. C ombat R ubber R aiding C raft ) ^[1] with outboard motors, each of which can accommodate 8 people, is used ^[14] . Despite the smaller secrecy of such a delivery, in this way more commandos can be delivered with greater speed ^{[15] [1]} (20 nodes ^[14] instead of 6-9 in the case of SDV ^[5] ). In this case, the boats are stored in the folded position inside the DDS module, and their number can be up to four units. When using rubber boats, disembarkation can be made in the surface and submerged positions of the boat. In the second case, combat swimmers inflate boats after surfacing ^[5] .

DSS modules are operated and maintained by members of SDV Team One-based batiscaph teams based in Pearl Harbor, Hawaii and SDV Team Two in Little Creek, Va. They are respectively subordinate to Special Operations Group No. 1 (Pacific) ( eng. Navy Special Warfare Groups One ) located in Coronado, California and No. 2 (Atlantic) in Little Creek, Virginia, with general subordination to the Naval Special Command Force Warfare Command ) in Coronado, California ^[1] . Overall control is provided by the US Special Operations Command ( US Special Operations Command ) Command in Tampa, Florida. Special Agreement Eng. Memoranda of Agreement (MOAs) is designed to ensure interaction between teams of special operations forces, submarine crews and their command ^[1] .

Training of special operations forces is carried out in special training centers at the locations of bathyscaph groups No. 1 and No. 2. The equipment of the training center allows you to perform all operations on working with DDS modules, including work under water with pressure corresponding to the working depth ^{[15] [1]} .

The estimated lifetime of the DDS module is 40 years. Preventive repairs are usually carried out by members of the servicing bathyscaph teams, sometimes with the help of crew members of submarines, every 18-26 months. Overhaul is carried out once every ten years at the shipyard. In the event of an overhaul, dismantling, checking and re-assembling of all components take place ^[1] .

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  Loading the SDV into the DDS module hangar.

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  Combat swimmer and SDV operator from the bathyscaphe group 2 during the exercise with the participation of USS Florida (SSGN 728)

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  Divers of the support team are ready to receive an SDV vehicle.

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  SEAL Team 5 members on a CRRC boat during an operation.

Torpedo submarines (maximum one module) and former SSBNs (up to two modules on each SSBN) were converted under the DDS module carriers. At present, 6 Stugegen-class submarines, 2 SSBNs of the Eten Allen type, and 2 SSBNs of the Benjamin Franklin type have been decommissioned.

As of the end of June 2010, five Los Angeles- class submarines and four former Ohio- class SSBNs are in operation. Initially, one of the Seawulf-type submarines and six Virginia- type submarines (another six are under construction) were built with space for the installation of one module.

• New opportunities for special operations forces of the US Navy // Arsenal magazine. - 2008. - Vol. 3 (inaccessible link)
• Dry Deck Shelter (eng.) . www.globalsecurity.org . The appeal date is July 11, 2010.