Momsen

Momsen refers to a specific type of underwater escape breathing apparatus. It is a closed-circuit rebreather originally developed by Charles Momsen of the United States Navy in the 1920s. This device was designed to allow submariners to escape from a disabled submarine.

The Momsen Lung, as it was commonly known, functioned by scrubbing carbon dioxide from the exhaled breath and replenishing oxygen from a small, high-pressure cylinder. This process allowed for extended underwater survival compared to simply holding one's breath. The apparatus typically consisted of a breathing bag, a mouthpiece, a CO2 absorbent canister (usually containing soda lime), and a small oxygen cylinder.

The Momsen Lung was a vital piece of equipment for submarine crews for many years, although its use had a limited success rate in actual escape attempts due to the inherent dangers and complexity of submarine escape. It has largely been superseded by more modern escape systems. The Momsen Lung is now primarily of historical significance.