■ - 





Two divers swam laps in the swimming pool while submerged. They 

 were asked to swim at a pace which they could maintain for long-duration 

 swims. The objective of the test was to obtain their subjective feelings 

 of heater interference with surface and underwater swimming. The results 

 of the swimming test are contained in Table 8. Speed loss was judged to 

 be noticeable, but not excessive. The divers indicated a preference for 

 the chest mock-ups although, subjectively, neither mock-up seemed to 

 interfere with their mobility. They felt that in the chest mode they 

 could retain the diver heater unit in emergencies. 



The mock-ups were further tested in conjunction with routine SDV- 

 type operations. Combat-type divers were required to swim approximately 

 one-half mile underwater and 100 yards on the surface using the back 

 pack and chest mock-up heaters. The test results were in the form of 

 subjective comparison by the divers. Interference with SDV operations 

 was noted. Also, the divers stated that they would prefer having the 

 heater mounted directly on a SDV in order to lessen the gear they have 

 to carry. 



RESULTS 



1. Noticeable, but not excessive drag, was observed from swimming with 

 the mock-ups. 



j , 



2. Divers preferred the chest mock-ups, because it would be possible to 

 retain the diver heater following ditching of the UBA. 



3. Interference with swimming or arm movements with either of the mock- 

 ups did not appear excessive. 



j 



4. Both mock-ups interferred with SDV-type operations. 



a. The chest unit resulted in difficulty in bending forward while 

 seated, thus interf erring with instrument reading. 



1 



b. Divers could not bend far enough forward wearing the chest unit 

 to open the flood doors of the SDV. 



c. While using the back pack mock-up, it was difficult to reach 

 the Navy Mark 6 UBA bypass valve and air ON-OFF switch. 



i 



5. Divers reported no difficulty in reading the displays. It was quite 

 ! ' simple to operate the controls using thin neoprene gloves; however, 



problems could be anticipated using three-fingered mittens. 



65 



