66 THE NAVY OCEAN ENGINEERING PROGRAM 



Communications 



Communications are essential for operational coordination between 

 submersibles and their support ships. Development of underwater voice 

 and telemetry links for search and recovery operations have been initiated. 

 These operations are planned to keep distances between submerged ve- 

 hicles and their support ships close enough to permit the use of under- 

 water sound for communication transmissions. 



This development for the DSRV and the DSSV will extend the range 

 of underwater "telephones" now used by the Navy. The development is 

 directed toward the provision of a communications capability at all depths 

 down to 20,000 ft, with lateral separations of the submerged and support 

 vessel up to three miles. The capability is to be provided for sea state 3 

 surface conditions, and for a reasonably uniform sound velocity profile 

 across the transmission path. Along with the voice capability of the 

 telephone, provisions wUl be made to enable the use of a transmitter- 

 receiver for sending and receiving telemetry signals on a time-shared basis 

 with voice signals. The telemetry portion of the system will process and 

 transfer data on navigation, Hfe support, and other submersible operations. 



The growing importance of saturation diving and underwater search, 

 rescue, and salvage techniques creates the need for improvements in rela- 

 tively short-range communications between the underwater base and 

 surface support ship base and free swimmers, and between swimmers. 



Communication links from the underwater base to a surface support 

 ship are now accompUshed via a cable to a telemetry surface buoy. 

 Unfortunately, the surface motion at high sea states degrades communi- 

 cations through umbilical cable links. Operational acoustic links are 

 limited to one mile ranges for voice-grade information transfer. 



The link from the underwater base to the free-swimming diver is opera- 

 tional for short ranges (up to 300 ft) by direct voice acoustic transducers. 

 For longer swimmer excursions, electronic receivers of the acoustic signal 

 currently in use will give reliable performance and have been suitably 

 miniaturized. When diver-to-base communications in excess of one mile 

 are required, investigation into the use of a telemetering buoy system will 

 be necessary. 



Diver-to-diver communications present a significant problem. In this 

 case the development effort is directed at an adequate oral-nasal mask, a 

 bone-conductive receiver-transmitter, and a solution to the problem of 

 synchronous breathing. Solutions to these and related problems are being 

 undertaken by the Navy. 



