CUMA (Canadian Underwater Mine-countermeasure Apparatus) (commercially called SIVA+) is a make of rebreather underwater breathing set designed and made in Canada for the Canadian Armed Forces by Fullerton Sherwood Engineering Ltd to replace the Royal Navy CDBA.[1]

The unit consists of a back mounted casing, containing its: carbon dioxide scrubber, oxygen supply, diluent supply (both spherical flasks), a mechanical ratio regulator, electronic PPO2 monitoring, and all of the valves and fittings. The remainder of the breathing loop consists of a pair of chest mounted counter lungs connected by the usual loop of wide corrugated breathing tubes running from and to the top of the backpack. It has a small bailout cylinder horizontally across the bottom of the backpack casing which is plumbed directly into the divers breathing loop.[1][2]

It is a self-mixing semi closed circuit rebreather (SCR). A constant flow of oxygen is mixed with a diluent volume dependent on the ambient pressure.[1] The deeper the diver dives, the more diluent is added, and thus the leaner the supplied breathing mix. The correct oxygen setpoint is monitored electronically and alerts the diver via a heads-up-display (HUD) if it is not being correctly maintained. The CUMA is capable for diving to a depth of 90 meters (295 feet) or a maximum working pressure of 10 ATA. It can be calibrated for the use of different diluents such as: air, trimix, heliox, or pure helium.[1]

Its first prototype set was made in March 1987.[1]

See also


  1. ^ a b c d e Chapple, JCB; Eaton, David J. "Development of the Canadian Underwater Mine Apparatus and the CUMA Mine Countermeasures dive system". Defence R&D Canada Technical Report (DCIEM 92–06). Defence R&D Canada. Archived from the original on August 8, 2009. Retrieved 2009-03-31.((cite journal)): CS1 maint: unfit URL (link)
  2. ^ Micjan, Ron (2006). "Canadian Forces CUMA Rebreather". Retrieved 2009-04-06.