Dry deck shelter

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 United States Navy's DDSs are 11.6 meters (38 feet) long by 2.7 meters (9 feet) high and wide, add about 30 tons to its host submarine's submerged displacement, can be transported by trucks or C-5 Galaxy aircraft, and require one to three days to install and test. They have three HY-80 steel sections within the outer glass-reinforced plastic (GRP) fairing: a spherical hyperbaric chamber at the forward end to treat injured divers; a smaller spherical transfer trunk; and a cylindrical hangar with elliptical ends. The hangar can support a swimmer delivery vehicle (SDV), four Navy SEALs to man the SDV, and a crew of Navy Divers to operate the DDS and launch the SDV; or 20 SEALs with four Combat Rubber Raiding Craft (CRRC). The SDV release team consists of 2 officers, 2 enlisted technicians, and 18 divers.

The two SEAL delivery vehicle teams report to Naval Special Warfare Group 3.

There are currently six portable dry deck shelters in use by the USN, the first one built by Electric Boat. The first, designated DDS-01S ("S" for starboard opening outer door), was completed in 1982. The remaining five, DDS-02P ("P" for port opening), -03P, -04S, -05S, and -06P, were built between 1987 and 1991 and were built by Newport News Shipbuilding. The shelters are maintained by a combined effort of navy divers stationed on the teams and workers of the maintenance company Oceaneering International. They have expected useful lives of about 40 years each.

List of Active and Future DDS-Capable Submarines
This list includes only active or future DDS-capable submarines. Virginia-class: NOTE: A total of 30 Virginia-class submarines are planned.
 * USS Virginia (SSN-774)
 * USS Texas (SSN-775)
 * USS Hawaii (SSN-776)
 * USS North Carolina (SSN-777)
 * USS New Hampshire (SSN-778)
 * USS New Mexico (SSN-779)
 * USS Missouri (SSN-780)
 * USS California (SSN-781)
 * USS Mississippi (SSN-782)
 * USS Minnesota (SSN-783)

Los Angeles-class: Seawolf-class: Ohio-class: NOTE: The Ohio-class SSGNs are capable of supporting dual Dry Deck Shelters.
 * USS Dallas (SSN-700)
 * USS La Jolla (SSN-701)
 * USS Buffalo (SSN-715)
 * USS Jimmy Carter (SSN-23)
 * USS Ohio (SSGN-726)
 * USS Michigan (SSGN-727)
 * USS Florida (SSGN-728)
 * USS Georgia (SSGN-729)

Astute-class:
 * HMS Astute (S119)
 * HMS Ambush (S120)
 * HMS Artful (S121)
 * HMS Audacious (S122)
 * HMS Anson (S124)
 * HMS Agamemnon (S123)
 * HMS Ajax (S125)