Operational Considerations for the Standby Diver in CUMA dives

Considérations opérationnelles quant au plongeur en alerte lors de plongées avec ACDSM

  1. Nishi, R.Y.
  2. Ward, A.J.
  3. D.J. Eaton
Corporate Authors
Defence R&D Canada - Toronto, Toronto ONT (CAN)
The Canadian Underwater Minecountermeasures (MCM) Apparatus (CUMA) is a self-contained, semi-closed circuit breathing apparatus in service with the Canadian Forces (CF) and other North Atlantic Treaty Organization (NATO) Navies for MCM diving to a depth of 81 metres of seawater (msw) using a mixture of helium and oxygen. Current CF rules state that a diver completing more than 30 minutes (min) of oxygen decompression has to be accompanied by a standby diver at the 9 metre decompression stop. As there are no specific repetitive diving rules governing such shallow dives on CUMA, the procedure of adding bottom times to determine the decompression requirements of a second dive must be used. As a result, the standby diver may become unavailable for a subsequent dive to deeper depths. This affects the operational ability of a small team to continue diving as the divers, including the standby become ‘dived out’ too quickly. Experimental dives to 9 msw to simulate a standby diver accompanying a CUMA diver were conducted in the DRDC Toronto Dive Research Facility to measure the inspired partial pressure of oxygen (PiO2). The results showed that the time-weighted average PiO2 after 30 min at 9 msw was greater than 1.3 atmospheres (absolute) (ATA). As a result, the inert gas loading should be minimal and there should be little or no decompression penalty associated with the standby diver diving again as a working CUMA diver. This will increase the operational ability of a small dive

Il y a un résumé en français ici.

Standby diver;Repetitive diving;Canadian Underwater Minecountermeasures Apparatus;CUMA;MCM;Circuit breathing;Standby diver;Inert gas loading;Decompression penalty;Shallow dives;Diver equipment
Report Number
DRDC-TORONTO-TM-2010-082 — Technical Memorandum
Date of publication
01 Nov 2010
Number of Pages
Electronic Document(PDF)

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