Because of their limited range, manned submersibles are carried to 

 their launch sites by mother ships. For instance, the Deep 

 Submergence Rescue Vehicle (DSRV) is carried by a catamaran 

 submarine rescue vessel or by a mother submarine. The catamaran 

 launches the DSRV by lowering the vehicle between the catamaran's 

 two hulls. The vehicle is thus protected from the hazards of wind and 

 wave during launch. In the principal method, the mother submarine 

 carries the DSRV on the after deck. To launch the vehicle, the 

 submarine surmerges, and the DSRV is uncoupled and swims away. 

 Because the DSRV is launched underwater, it is protected from both 

 wind and wave during this critical period. It may also be so launched 

 under ice. Two DSRV's, capable of deployment from catamarans or 

 submarines, will be in limited service for 5000 foot underwater 

 rescue operations by December 1973 and in full service by July 1974. 

 Another type of launch platform, a semi-submerged ship, is under 

 construction. It consists of two cylindrical hulls connected by pylons 

 to a platform above. Because its hulls will be submerged and thus not 

 susceptible to surface wave action, the vessel will remain relatively 

 stable during launch and recovery operations. This ship can serve as 

 the tender for the RUWS. 



Conventional underwater salvage systems require divers to 

 tunnel under sunken ships to secure lifting chains around the hull. In 

 this method, there is always the danger of diver entrapment beneath 

 the hull by a tunnel cave-in or backfill. The Large Object Salvage 

 System (LOSS), now under development, will carry out salvage 

 operations without divers. The principal unit of the LOSS system is 

 a self-positioning, underwater pontoon that can lift 100 tons. By 

 using several pontoons hooked together, the system will be able to 

 lift aircraft or submarines from depths of 1,000 feet. The LOSS 

 pontoon is controlled via cable from a command center aboard a 

 surface support ship. The pontoon will carry articulated attachment 

 arms, explosive pins that can be secured to the wreck, buoyancy 

 generating systems, and sensors. 



Acoustic Navigation Systems 



To accomplish useful work in the sea, man must be able to locate 

 objects and remain at or return safely to a given spot with a minimum 

 expenditure of time and effort. Because sound propagates in water 

 with less attenuation than any other known energy form, the need for 

 accurate, deep ocean navigation is being met through the use of 

 acoustics. 



There are problems, however, which must be considered in the use 

 of present-day acoustic systems. An underwater object cannot be 

 acoustically located if hidden behind an underwater ridge. The 

 sound waves will either be blocked by the ridge or will bounce off the 

 jagged surface of the ridge several times, resulting in a confusion of 

 sound echoes. To overcome the problems of sound wave blocking 



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