Royal Navy CDBA Bailout System

Royal Navy CDBA Bailout Subsystem

The CDBA is unique among military rebreathers in that it provides a bailout system for the diver. This system comprises two small aluminum cylinders, mounted on the front of the rig, which directly feed a supply of pure 02 to the diver's counterlung in the event of any problem with the main gas supply system. Interestingly enough, several ex-forced divers with whom I correspond told me that it was a generally accepted procedure to simply remove the main cylinders and to use the front cylinders alone when diving in depths shallower than 25 feet, thus converting the CDBA to a pure 02 rebreather by the simple expedient of removing the nitrox system completely from the chassis.

The two small cylinders are manifolded to each other and are provided with a simple on/off valve for gas control.

The O2 is carried to the counterlung with a high pressure hose, the left-most of the two shown here. No reduction regulator is provided, the high pressure being fed directly to the rig.

Cylinders are held in a pocket mounted on the front vest of the rig, directly under the scrubber and counterlung assembly.

Inlet hose is rotated 90 degrees for attachment and removal. This action is impossible once the cylinders are secured, thus inadvertent disconnection is precluded.

Inlet connection is directly to the counterlung at the right hand top of the counterlung. The knob above the connection is the needle-valve for control of bailout gas into the counterlung.

This system is about as simple as it gets, with no regulator or any other mechanism other than a simple on/off valve. As with all other aspects of the CDBA, rugged simplicity is the engineering goal, and this goal was well achieved.

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		The two small cylinders are manifolded to each other and are provided with a simple on/off valve for gas control.
		The O2 is carried to the counterlung with a high pressure hose, the left-most of the two shown here. No reduction regulator is provided, the high pressure being fed directly to the rig.
		Cylinders are held in a pocket mounted on the front vest of the rig, directly under the scrubber and counterlung assembly.
		Inlet hose is rotated 90 degrees for attachment and removal. This action is impossible once the cylinders are secured, thus inadvertent disconnection is precluded.
		Inlet connection is directly to the counterlung at the right hand top of the counterlung. The knob above the connection is the needle-valve for control of bailout gas into the counterlung.