dives to greater depths from habits enplaced 300 to 1.000 feet deep. The 

 developmental work was supported by the Manned Undersea Science 

 and Technology (MUST) office of NOAA. 



To obtain data for use in preparing the tables, divers descended from 

 the 30-foot-depth level and ascended from 60-. 90-. and 120-foot levels. 

 Maximum descents of 250 feet were made from 90- and 120-foot-depth 

 levels. In these experiments, it was discovered that a diver could go from 

 the 100- to the 200-foot level for 125 minutes without the need for a 

 decompression stop on the way back. Where decompression was re- 

 quired, the project determined the necessary duration and depth levels 

 of the stops. This information is contained in the tables. 



In a project to improve diver equipment, a new acoustic diver com- 

 munication system is being developed. The standard set for the new 

 communicator is that, at a depth of 1,000 feet, in water temperature 

 ranging from 29° to 100° F, a random word list should be 60-percent in- 

 telligible over a range of 2,000 yards. This standard would assure a high 

 level of intelligibility for phrases and sentences transmitted under the 

 same conditions. The system will provide communication between 

 divers and between swimmers and distant delivery vehicles, sub- 

 marines, and surface craft. The communicator is being designed for easy 

 handling by a SCUBA (swimming) diver. 



The USN new Ocean Simulation Facility, housing the world's largest 

 hyperbaric chamber complex, is now in full operation. The $12 million 

 facility is certified for testing and evaluating diver and equipment reac- 

 tions to a depth equivalent to 2.250 feet of seawater. Nearly all environ- 

 mental conditions found in the ocean can be simulated under laboratory 

 control at the facility. 



The core of the facility is the hyperbaric complex that consists of a 

 55,000-gallon "wet" chamber and five dry chambers, all interconnected, 

 with fully automated closed-circuit life support systems and computer 

 facilities. Another feature is the high-pressure, gas storage bottle field. It 

 is the source of all gas for pneumatic control pressure, life support gases, 

 and chamber-pressurizing gases. The bottle fields have a capacity of 

 about 836,000 standard ft^ of gases. This amount can be augmented dur- 

 ing deep dives by gases from commercial trailers. 



Located at the Naval Coastal Systems Laboratory in Panama City. 

 Florida, the facility will serve as a national center available to Govern- 

 ment, academic, and industrial laboratories for research, development, 

 testing, and evaluation of systems and hardware used by divers in the 

 ocean environment. 



SUBMERSIBLE OPERATOR AIDS 



New materials and equipment including acoustic sensors described 

 earlier in this chapter are important in the development of better sub- 



68 



