Momsen Lung

The Momsen lung was a primitive underwater rebreather used before and during World War II by American submariners as emergency escape gear. The Momsen lung was invented by Charles B. Momsen (nicknamed "Swede"). Submariners would train in an 80 ft (24 m) deep Escape Training Tank at New London or Pearl Harbor using this apparatus. It was first introduced as standard equipment on P- (Porpoise-) and Salmon-class boats.

The device recycled the breathing gas by using a counterlung containing soda lime to scrub carbon dioxide. The lung was initially filled with oxygen and connected to a mouthpiece via twin hoses containing one-way valves: one for breathing in and the other for breathing out.

The only known emergency use of the Momsen lung is during the escape from Tang on 25 October 1944. Thirteen men (of thirty survivors) left the forward escape trunk: five were picked up by the Japanese; three more reached the surface "but were unable to hang on or breathe and floated off and drowned"; the fate of the other five is unknown. Not all the escapees from the trunk used the Momsen lung. An officer had his mouthpiece knocked out shortly after leaving the submarine. One of the trunk ascents was made without a Momsen lung. Many were unable to leave the trunk or discouraged from attempting an escape. Most of the crew perished.

The Momsen lung was replaced by the Steinke hood beginning in 1962.

...
Wikipedia