Momsen lung

Momsen lung
Name	Momsen lung
Caption	Escape apparatus for submarine crew
Invented by	Charles B. Momsen
Country	United States
Year	1930s
Used by	United States Navy
Type	rebreather escape device

Momsen lung The Momsen lung was an early submarine escape rebreather developed in the 1930s by Charles B. Momsen for use by United States Navy submariners trapped in disabled vessels. It provided a closed-circuit breathing loop with a carbon dioxide scrubber to permit controlled ascents from depth, and became associated with procedural changes in United States Navy submarine escape doctrine and training at bases such as New London Submarine Base and schools like the Naval Submarine School. The device influenced later apparatus and international safety standards for submarine escape and influenced organizations including Royal Navy and Krupp-era submarine design discussions.

History

Development began after high-profile submarine incidents such as the loss of USS S‑51 (SS‑162) and the sinking of USS S‑4 (SS‑109), which underscored the need for improved escape equipment for crews operating from bases like Pearl Harbor and Norfolk Naval Shipyard. Charles B. Momsen, then attached to Bureau of Construction and Repair and later the Office of the Chief of Naval Operations, led trials informed by work at institutions including Naval Experimental Station and collaboration with manufacturers tied to Westinghouse and General Electric for materials and testing rigs. Sea trials combined training at Submarine Base New London with rescue experiments inspired by earlier salvage efforts linked to William Beebe and the deep-sea work of Otto Diederichs. The device entered fleet distribution aboard Gato-class submarine and Sargo-class submarine types prior to World War II and featured in interwar debates in journals such as Proceedings (US Naval Institute) and discussions at Naval War College.

Design and components

The Momsen lung assembly consisted of a mouthpiece and hose connected to a flexible bag and a canister of soda lime scrubber housed in a compact frame intended to be strapped to a sailor’s chest. Components drew on material advances used in Panama Canal-era diving gear and poisons control technology developed in chemical industries allied with DuPont and Union Carbide. The rebreather bag and nonreturn valves resembled features later adopted in Davis Submerged Escape Apparatus studies and in experimental gear tested at Brooklyn Navy Yard. The design incorporated a one-way valve system, exhaust valve, and a manually operable overpressure valve similar in concept to devices demonstrated in Royal Navy trials and in demonstrations before committees chaired by officers from Submarine Force, U.S. Pacific Fleet. The device packaging allowed storage within submarine escape trunks and on deck escape hatches standardized after consultations at Bureau of Ships.

Principles of operation

The apparatus operated as a closed-circuit rebreather: exhaled gases passed through a canister of soda lime where carbon dioxide was chemically absorbed, while oxygen content was conserved in the breathing loop to limit nitrogen supersaturation and bubble formation during ascent. The system relied on controlled exhalation techniques taught in conjunction with ascent procedures modeled after decompression protocols discussed at Undersea Medical Society meetings and in papers by physiologists connected to Harvard Medical School and Johns Hopkins Hospital. The Momsen lung sought to mitigate pulmonary barotrauma risks noted in incidents studied by investigators from Navy Submarine Medical Center and echoed in reports considered by committees at Congressional Subcommittee on Naval Affairs.

Training and use

Training for the device became standard at facilities including Naval Submarine School, Submarine Escape Training Tank, HMS Dolphin (in comparative exercises with Royal Navy counterparts), and through exercises conducted out of Pearl Harbor Naval Shipyard. Sailors practiced donning procedures, exhalation-controlled ascent, and mouthpiece management under instructors who were alumni of Naval Academy and veterans of salvage operations from incidents like USS S‑4 inquiry. Routine drills integrated the Momsen lung with escape trunk procedures and coordinated with rescue vessels such as USS Falcon (AM-28)-type ships and salvage units familiar from Battle of the Atlantic convoy operations. Manuals and shipboard standing orders issued by Commander Submarine Force, U.S. Atlantic Fleet and Commander Submarine Force, U.S. Pacific Fleet codified deployment techniques.

Operational performance and limitations

Operational use showed the Momsen lung could allow some submariners to survive ascents from moderate depths, but real-world performance varied with physical conditioning, sea state, and hull angle. Limitations included restricted oxygen supply for prolonged entrapments, potential for canister saturation, and the risk of hypoxia if not used with proper technique—issues examined in post-incident inquiries exemplified by the USS Squalus (SS-192) salvage and rescue operations overseen by Charles F. "Swede" Momsen’s contemporaries. The apparatus also proved less effective in cold-water environments encountered near Aleutian Islands deployments and in cases involving extensive hull flooding or entanglement. Such constraints prompted debates within Office of Naval Inspector General and influenced decisions during fleet modernization programs in the run-up to World War II.

Legacy and influence on diving safety

Although later superseded by escape systems like the Steinke hood and modern submarine escape immersion equipment developed with contributions from institutions like National Oceanic and Atmospheric Administration and standards bodies including International Maritime Organization, the Momsen lung left a lasting imprint on submarine escape doctrine, training curricula at Naval Submarine School, and salvage practice codified in naval manuals. Its development accelerated collaboration between naval engineering bureaus, medical research centers such as Naval Medical Research Center, and industrial partners like Edison Laboratories and General Dynamics Electric Boat. Lessons learned informed the design of subsequent rebreathers, influenced international protocols that involved Royal Navy and French Navy exchanges, and are referenced in historical treatments published by United States Naval Institute and chronicled in biographies of figures like Charles B. Momsen and contemporaries involved in undersea rescue.

Category:Submarine escape equipment