U. S . NAVY'S DEEP SUBMERGENCE FORCES By CAPT James P.WEOH 11, USM Suhrine Development GroupOhT San Diego, CA 92106 ABSTRACT Since its inception in 1970, Submarine Developmenta?d a biomedical research department. The greatest Group OWE113s functioned astine U. S. Navy's sole wealth of experience to date, however, has been with operating arm for underwater search, recovery, and deep suhergence vehicles. Hence, this paper will be rescue. As such, it maintains the largest, most directed toward recent experiences with these systems. diverse collection of DeepSuhergence assets in the world, including submarines, manned and unmanned sub- DEEP SUBMERGENCE RESCUE mersibles, search systems, diving systems, surface ships, and shore facilities. A wealth of operational The Deep Submergence Rescue Vehicle(DSRV) system experiences have been acquired with these assets overhas been designed to providea quick-reaction, world- the past thirteen years in both Atlantic and Pacificwide capability to rescue personnel from a disabled Oceans, leading to the establishrnent of numerous tech-submarine, lying on the ocean atfloor less than niques and equipment developments. This paper will collapse depth. describe specific Subnarine Development Group systems and present results of several recent operations. Each of the Navy's two DSRV's (IUSTIC and AVALON) -Future glans will also be discussed. are designed to mate over the hatch of a disabled submarine and, with a crew of three, carry24 up to INTRODUCTION rescuees per trip back to safety. The outer hull, made of fiberglass reinforced plastic, 50 is feet in length The U. S. Navy's operational command for deep sub- and 8 feet in diameter. Within the lightweight outer mergence systems is Submarine Development GroupONE hull are three interconnected spheres, eachli meters located in San giego, California. The Development in outside diameter and made of HY-140 steel. Each Group was established in 1967 by the Chief of Navalvehicle has an air weight 75,000 of lbs and is capable Operations as part of the Pacific Submarine Force. It of submerging to a depth 5,000 of feet. acts as the Naxy'ssole operating arm devoted to the development of deep submergence capabilities for search, Propulsion and maneuvering of the DSRV is achieved location, recovery, and rescue anywhere in the world'sby an electrically-powered stern propeller within a oceans. moveable control shroud and four electrically-powered ducted thrusters (two horizontal and two vertical). Establishment of the Development Group was an out-The DSRV is designed to hover in currents up to one growth of the Deep Submergence Systems Review Group knot and mate with a disabled submarine lying on the established by the Secretary of the Navy1963 in after ocean floor at angles up 45 to degrees. Each vehicle the loss of the Submarine THRESHEX and the demonstratedhas a subinerged enduranceof approximately eight hours. inadequacy of the Navy's deep ocean capabilities as revealed in the searches for the THRESHER in 1963 andSpecial sensors and equipment necessary for 1964 and the H-Bomb off Palomares, Spain1966. in navigation, location and safety include a horizontal Prior to 1967, deep ocean capabilities, where they obstacle avoidance sonar, vertical obstacle avoidance existed at all, rested almost entirely in various sonar, altitude/depth sonar, and short range sonar prototype and "one-of-a-kind" systems. These were com- which outlines any object directly beneath the DSXV monly operated by numerous organizations suchas Navy mating skirt and assists in determining the orientation laboratories, universities, and other institutions of the disabled submarine. Tn addition, each DSRV has generally supported by research and development funds.a doppler sonar, transponder interrogation sonar, Historically, the operating forcesof the Kavy (i.e., television and 35mm still cameras, external flood Fleet) were forced to rely on this mixture of deeplights, and viewports in the forward and middle spheres. ocean assets to respond to contingency operations. MYSTIC In the ten years since its inception, however, the Development Group has centralized the Navy's deep sub- Located atthe Submarine Xescue Unit at North mergence operational experience and assembled the Island Naval Air Station, San Diego, California, each largest array of diverse deep ocean assets ever operatedDSRV and its associated support equipment is capable and maintained under one organization, civilian or of being air transported by three Air Force C-141A military. These assets include deep suhergence aircraft. At-sea support is to be provided either by vehicles, deep submergence rescue vehicles, support a new catamaran ASR-21 Class Submarine Rescue Ship or ships, a deep diving research submarine, submarine an 58x437 Class nuclear attack submarine modified to rescue ships, advanced saturation diving systems, serve as a Mother Submarine, capable of transporting, schools for training divers and deep subnergence replenishing, launching, and recovering the DSRV while vehicles operators, shore-based maintenance activities,submerged. 379 US. Government work not protected by U.S. copyright. During 1982, MYSTIC conducted two operations of note. The first, taking place during August, was an Alternate Mission Exercise involving equipment and procedures not normally used in the rescue scenario; rather, these operations capitalizedon the usefulness of the DSRVas a search/work platform. The Alternate Xission Package consists of a dual range sidescan sonar, binocular optics, two television monitors, video tape recorder, and16mm picture camera. During the August time frame, MYSTIC was tasked to search for and identify various objects such as a submarine anchor and deep seat training fixture. The boat successfully operated in a beacon field and exercised all system components in consort with standard onboard functions. These operations pro- vided valuable training which will be applied toward future problems suchas torpedo and aircraft recovery. During the period 6-22 December1982, the MYSTIC Figure 2. MYSTIC being positioned on center well participated in a flyaway exercise to Charleston, cradle of ASR-22ORTOLAN. South Carolina. This exercise was both for training and for the certification of the twin- DOLPHIN hulled ASR, USS ORTOLAN, for launch, recovery, and tracking of the DSRV. USS DOLPHIN (AGSS-555) is the Navy's deep diving submarine. The ship conducts weapons, acoustic, The DSRV system was loaded aboardC-141s two and environmental, marine engineering, and tactical op- one C-5A (figure1) for the flight-from North Island erations in support of the Navy's research and devel- Naval Air Station in San Diego, homeport for the opment communities. Manned by a crew of three off- DSRV'S. icers and twenty-six enlisted men, DOLPHIN is capable of carrying over twelve tons of scientific equipment to sea for periodsas long as three weeks. The ship can deploy from her San Diego, California homeport for out-of-area operations extendingto upseveral months. In April1982, the ship conducted two weeks of highly productive upper Ocean turbulence experiments to examine near-surface seawater mixing off the coast of Southern California. The ship carried an instru- ment cluster mounted on a nine thousand pound tripod mounted on the forward deck (figure3). Half of these operations were conducted in consort with the R/V ACANIA. The operation was sponsored by the Naval Postgraduate Schoolat Monterey, California and the University of British Columbia in Vancouver, British Columbia, Canada. Figure 1. DSRV-1 MYSTIC being loaded intoC-5A for flyaway exercise to Charleston, South Carolina. Once at Charleston, the system was highway transported to the naval base on itsown trailers. The MYSTIC was fit up on the submarine,USS SEAHORSE (SSN-6691, which was to actas a mother submarine(NOSUB) for recovery backup and alsoas a training aid for dock- ing and seating. The MYSTIC was then installedon USS ORTOLAN (figure2) and transported to a dive site south of Grand Bahama Island,Two dives, numbers411 and 412, were conducted in this area with successful launches and recoveries using the center well-lowered cradle of ORTOLAN and several locations and landings on the submergedSEAHORSE. Following this exercise, the system was taken back to base and offloaded for transport to Charleston Air Force Base and the sub- sequent flight home. Not only was this an effective Figure 3. USS DOLPHIN shown with turbulence probe training and certification evaluation, it also gave tripod mounted on bow. additional credibilityto the practice of quickly transporting a complex system several thousand miles away and having it perform reliablyat its destination. During February 1983, the ship conducted a ten day "Deep Tow Sonar Array" operation in support of on-going research sponsored by the Naval Ocean Systems Center, San Diego, California. In this operation, a 380 four thousand foot passive sonar array was towed awayby from SCI than previously thought; the was range a six thousand foot coaxial tow cable. The tow cableable to accurately directSEA CLIFF to ahydrophone length was adjusted by means 12,000of a lb. location, thus verifying range accuracy forsub- a hydraulically-driven winch mounted externally on the merged target; constant depth comparisons SEAwith ship's forward deck. This operation satisfactorily CLIFF depth sensors versus range computed depth denorstrated the PeepTow System and helped to estab- provided a basis for rangedepthn accuracy. This was lish the baseline operation