Special Operations.Com
Dry
Deck Shelters (DDS)
Focus
Feature
USS
Kamehameha (SSN-642)
Overview
The DDS gives a submarine (host ship)
the capability of participating in special operations
involving the swimmer Delivery Vehicle (SDV).
The DDS allows launch and recovery of one or two SDVs
while the host ship is submerged. The installation
of the DDS does not affect the performance of the
host ship appreciably. The few permanent modifications
made to the ship do not degrade ship performance after
the DDS has been removed.
The DDS consists of three pressure modules
constructed as one integral unit: a hangar in which
the SDV and other system equipment are stowed. a transfer
trunk to allow passage between the modules and the
host ship, and a hyperbaric chamber for decompression
and recompression treatment of diverts. Penetrations
between DDS modules are made through the attachment
rings, which have faces to accommodate the penetrations.
The DDS provides a working environment at 1 atmosphere
for the mission team during transit and has structural
integrity to text depth of the host ship. The
DDS can be provided with a hangar door that opens
to starboard or port.
Dry Deck
Shelters—Deploying Special Operations Forces from
Submarines
by Steve Southard
Dry Deck Shelters (DDSs) provide specially configured
nuclear powered submarines with a greater
capability of deploying Special Operations Forces
(SOF). DDSs can transport, deploy, and recover
SOF teams from Combat Rubber Raiding Crafts (CRRCs)
or SEAL Delivery Vehicles (SDVs), all
while remaining submerged. In an era of littoral warfare,
this capability substantially enhances the combat
flexibility of both the submarine and SOF commandos.
Dry Deck Shelter (DDS)-01S sits
atop USS Dallas (SSN 700) in June
1998, following the first fit-up of a
DDS to a Los Angeles (SSN 688)
Class submarine.
History
Ever since Jules Verne’s fictional Nautilus and Simon
Lake’s early submarines, the deployment of
divers from submerged submarines has captured imaginations.
Frogmen in World War II conducted
clandestine operations from the diesel-electric submarines
of the period. Divers have long envisioned
submarines specially equipped for their unique needs,
including the use of a more spacious
lock-out/lock-in chamber. USS Grayback (SS 574) contained
two such chambers and used this
capability from 1969 to 1983. On January 16, 1982,
five Navy divers died in the starboard chamber
when a vacuum was rapidly drawn. Following the investigation,
substantial upgrading of design,
procedures, and training took place in Deep Submergence
Systems.
The concept of a detachable Dry Deck Shelter with
the ability to house, deploy, and retrieve SDVs,
was born in the late 1970s. The Electric Boat Division
of General Dynamics Corporation completed
DDS-01S in 1982. [Note: The number indicates its order
of construction, and the “S” indicates that its
outer hangar door opens to the starboard side.] Newport
News Shipbuilding completed the
construction of DDS-02P, -03P, -04S, -05S, and -06P
between 1987 and 1991. The following
submarines once accommodated DDSs but have since been
decommissioned: USS John Marshall
(SSN 611), USS Sam Houston (SSN 609), USS Silversides
(SSN 679), USS Archerfish (SSN
678), USS Cavalla (SSN 684), and USS Tunny (SSN 682).
Submarines currently configured for
DDS use are USS William H Bates (SSN 680), USS L Mendel
Rivers (SSN 686), USS
Kamehameha (SSN 642), USS James K Polk (SSN 645),
and USS Dallas (SSN 700).
Ugly but functional, a Dry Deck
Shelter rests on blocks at one of two
shore-based training facilities. Some
fairing panels have been removed to
allow access to mounting bolts.
Description
The portable DDS is designed for temporary installation
on modified host submarines. To date, DDSs
have been operated from four former ballastic missile
(i.e., Benjamin Franklin Class) submarines and
six submarines of the Sturgeon (SSN 637) Class. Installations
on additional Los Angeles (SSN 688)
and Seawolf (SSN 21) Class submarines, as well as
Virginia Class attack submarines, are planned in
the future.
Overall, the DDS is 9 feet wide, 9 feet high, 38 feet
long, and displaces 30 tons. It consists of three
interconnected compartments made of HY-80 steel within
a fiberglass fairing, each capable of
independent pressurization to a depth of at least
130 feet. The forward-most compartment, a sphere,
is
the hyperbaric chamber which is used for treatment
of injured divers. In the middle compartment, or
transfer trunk, operators enter and exit the submarine
and/or either of the other compartments. The third
compartment, the hangar, is a cylinder with elliptical
ends which houses either the SDV or up to 20 SOF
personnel with CRRCs.
The DDS may be transported to its host ship by barge,
trucked over land, or flown via C5A aircraft.
Each DDS has a specially designed truck called a “transporter”
for this purpose. Complete on-loading
and testing to make the DDS ready for manned operations
at-sea takes from 1-3 days.
Two shelters can be installed aboard Benjamin Franklin
Class submarines; other submarine classes
are single-shelter ships. Modifications to a submarine
allow it to serve as a DDS host ship. These
include mating hatch modifications; addition of electrical
penetrations, valves, and piping for ventilation;
divers’ air; and draining water.
A routine onload of Dry Deck Shelter
(DDS)-04S aboard USS Kamehameha (SSN
642), one of two dual-shelter host ships.
DDS Operation
The two major mission areas for the DDS are SDV launch
and recovery, and Mass Swimmer
Lock-Out (MSLO). For SDV missions, Mark 8 Mod 0 or
Mod 1 SDVs are generally used, although
the DDS can also accommodate the Mark 9 SDV. The miniature
wet submersible sits on a cradle within
the DDS hangar until ready for use. After flooding
the hangar and equalizing it with outside pressure,
the
DDS operators open the hangar’s large outer door and
wheel out a track onto the topside surface of the
submarine. The cradle and SDV roll out on the track,
and the SDV departs. DDS operators then return
to the submarine or may remain outside. After conducting
their mission, SDV operators locate the
submarine by means of an active pinging sonar. When
the SDV returns, divers secure it to its cradle,
winch it back into the DDS, and shut the hangar outer
door.
MSLO operations may be performed with the submarine
surfaced, submerged, or awash. Generally, the
SOF team uses CRRCs, large rubber rafts with outboard
motors. The rafts are stored rolled up within
the hangar until ready for use, and then are inflated
on deck. Though less clandestine than SDVs,
CRRCs can insert more commandos into an area more
quickly, an advantage for some missions against
particular threats.
DDSs are operated and maintained by members of SDV
Team One in Pearl Harbor, Hawaii, and SDV
Team Two in Little Creek, Virginia. The SDV Teams
report to Navy Special Warfare Groups One and
Two, which report to Naval Special Warfare Command
in Coronado, California. U.S. Special
Operations Command, a joint command in Tampa, Florida,
oversees all of these organizations.
Memoranda of Agreement (MOAs) provide the proper interface
between the SOF community and the
submarine crews, squadrons, and submarine Type Commanders.
Special Operations Forces may train aboard a DDS at
one of two specially outfitted training facilities
at
the SDV Team locations. Each training facility has
the capacity for conducting wet, pressurized training
of DDS operators.
With all fiberglass fairings removed,
this Dry Deck Shelter reveals its three
internal compartments.
Maintenance and Services
Normally SDV Teams perform preventative maintenance
with standard maintenance requirement cards.
However, when an MOA is in effect, the submarine crew
performs some of the Planned Maintenance
Schedule (PMS) requirements. Restricted availabilities
are conducted every 18-26 months, usually at
the depot level but occasionally by the SDV Teams
themselves. Regular overhauls occur every ten years
at the depot level. These are complete overhauls during
which the depot removes, refurbishes, and
reinstalls all components.
Planning Yard services are provided by Newport News
Shipbuilding under the oversight of the
Supervisor of Shipbuilding, Conversion, and Repair
(SUPSHIP) in Newport News, Virginia. Several
other organizations including the Submarine Maintenance
Engineering Planning and Procurement Agency
(SUBMEPP); Portsmouth Naval Shipyard; the Naval Experimental
Dive Unit (NEDU); the Naval
Surface Warfare Center (NSWC), Annapolis; the Fleet
Technical Support Center (FTSC), Pacific; and
Electric Boat Corporation provide support to the program.
Future
of the DDS Program
Four Los Angeles (SSN 688) Class submarines, in addition
to USS Dallas (SSN 700), are slated for
conversion to be DDS host ships. To date, modifications
are nearly complete on USS Los Angeles
(SSN 688) and USS Buffalo (SSN 715). Conversion of
USS Philadelphia (SSN 690) has begun,
and work on USS La Jolla (SSN 701) will commence in
Fiscal Year 2000.
Following these conversions, USS Jimmy Carter (SSN
23) will undergo similar modification. Several
hulls of the Virginia Class Attack Submarine will
serve as DDS hosts as well. All Virginia Class
submarines will also contain an integral Lock-Out
Trunk capable of deploying nine divers and their
equipment. It is possible that some of the early USS
Ohio (SSBN 726) Class submarines may also
become host platforms.
With an expected service life of at least 40 years,
Dry Deck Shelters will likely continue to support
the
missions of Seal Delivery Vehicle deployment and Mass
Swimmer Lock-Out, serving both the Special
Operations Forces and submarine warfare specialties
for many years to come.
Additional
Information
For further information on the DDS Program, contact:
Tom Lewis, NAVSEA PMS395A2; DSN: 332-6701; commercial:
703-602-6701; fax:
703-602-6653; e-mail: Lewis_Tom@HQ.NAVSEA.NAVY.MIL
.
Steve Southard, NAVSEA PMS395A22; DSN: 332-6701; commercial:
703-602-6701 x222;
fax: 703-602-6653; e-mail: Suthard_Steven_R@HQ.NAVSEA.NAVY.MIL
.
Steve Southard is the Dry Deck Shelter Project Officer
in the Support Submarines/Special
Warfare Branch of the Deep Submergence Program Office
within NAVSEA’s Submarine
Directorate.
