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Manned Testing of Fullerton Sherwood SIVA 55-VSW Underwater Breathing Apparatus (UBA) for Very Shallow Water (VSW) Mine Countermeasure (MCM) Missions,

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Technical rept. Jun 98-Nov 99

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Presently, no specific diving apparatus on the Authorized for Navy Use ANU list meets the demands set forth by the CNO to conduct very shallow water mine countermeasure VSW MCM operations. NEDU was tasked to test and evaluate the Fullerton Sherwood SIVA 55-VSW Underwater Breathing Apparatus UBA, to determine whether it will maintain a sufficient O2 fraction to support a working diver from the surface to 60 fsw 10.4 msw. Using a 30 70 N2 O2 mix, NSDU personnel conducted at least 16 SIVA 55 dives each in 77 deg - 3 deg F 25 deg - 1.7 deg C water in the 15 ft. 4.6 mew deep NSDU test pool, and at 40 and 60 few 12.2 and 18.4 mew in the NEDU Ocean Simulation Facility OSF. Divers conducted manufacturer-sanctioned UBA purges on the surface and an additional purge after reaching the bottom, rested five to 10 minutes, then pedaled on underwater ergometers for 30 minutes each at 50 and 75 watts. During test pool dives, nearly a quarter of the divers UBAs reached potentially hypoxic levels. We conducted another set of test pool dives and determined that setting the buoyancy control valve BCV half-open-vice one-quarter open during the first series-ensured adequate UBA O2 concentrations. At 40 few nearly half of the divers UBA PO2 remained above 1.3 ATA after 10 minutes of exercise mean 1.34 ATA range 1.09 - 1.45 ATA but, for all but one diver, dropped below 1.3 ATA within 13 minutes. Average PD during the initial 10 minute rest period was 1.41 ATA. At 60 few we halted testing after four dives due to high PO2 levels mean 1.63 ATA. Because the U.S. Navy Diving Manual authorizes divers PO2 to reach 1.4 ATA without Commanding Officer CO authorization- and 1.6 ATA with CO authorization-we recommend that the SIVA 55-VSW be accepted and authorized for use by the VSW MCM detachment with the following caveats 1 Never plan dives exceeding 40 few 2 complete a thorough UBA purge prior to entering the water and before ascending.

Subject Categories:

  • Stress Physiology
  • Hydrology, Limnology and Potamology
  • Land Mine Warfare

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