The Momsen Lung

The Momsen lung was a early underwater rebreather used prior to and during World War II by American submariners as emergency escape gear.

While serving with the Submarine Safety Test Unit, Charles Momsen began working on a device to help sailors surface. It was officially called the Submarine Escape Lung, it consisted of an oblong rubber bag that recycled exhaled air. The press enthusiastically received the device and dubbed it the Momsen Lung, a name that stuck.

The Lung contained a canister of soda lime, which removed poisonous carbon dioxide from exhaled air and then replenished the air with oxygen. Two tubes led from the bag to a mouthpiece: one to inhale oxygen and the other to exhale carbon dioxide. The device hung around the neck and strapped around the waist. Besides providing oxygen for the ascent, it also allowed a submariner to rise slowly to the surface, thus avoiding decompression sickness (“the bends”).

Between June 1929 and September 1932, then-Lt. Momsen developed the lung with Chief Gunner’s Mate Clarence L. Tibbals and Frank M. Hobson, a civilian employee of the Bureau of Ships. In 1929, Momsen received the Distinguished Service Medal for personally testing the device at a depth of 200 feet (61 m). The Lung saved its first lives in October 1944, when eight submariners used it to reach the surface after Tang (SS-306) sank in 180 feet (55 m) of water in the East China Sea. The Lung was eventually supplemented by the Steinke hood and free-ascent techniques.