Christian Lambertsen and the word SCUBA.

Who Lambertsen was

The National Academy of Engineering's memorial tribute to Christian J. Lambertsen, written by Tom Hawkins and published in 2012, gives his birth year as 1917 and his death as 11 February 2011, aged 93. It says he took a B.S. at Rutgers in 1938 and an M.D. at the University of Pennsylvania in 1943. Two details differ elsewhere. Wikipedia's infobox gives his birth as 15 May 1917 in Westfield, New Jersey, while a New York Times citation in the same article gives 17 May. A search summary of other sources gives 1939 for the Rutgers degree; we could not confirm that version.

A bubble-free rebreather

Lambertsen's invention was a closed-circuit rebreather, designed while he was still a student. Wikipedia says he designed a series of rebreathers from 1940, with a patent filed on 16 December 1940 and issued on 2 May 1944. Defense Media Network (Dwight Jon Zimmerman, 30 August 2018) says he modelled the LARU Mark I in 1940 and calls it the first underwater rebreather that let a diver move without bubbles showing at the surface.

The NAE tribute says Lambertsen presented his self-contained underwater swimming apparatus to the Office of Strategic Services (OSS) as a 23-year-old medical student. It was first called the Lambertsen Lung and later the Lambertsen Amphibious Respiratory Unit, or LARU. When that demonstration took place is told differently:

• Defense Media Network describes a demonstration in April 1942 attended by representatives of the US Navy, the British Special Operations Executive and the OSS.
• The NAE tribute's "23-year-old" would place his presentation around 1940.
• Wikipedia gives no exact year.

The OSS Maritime Unit

Defense Media Network says the OSS recruited Lambertsen in June 1943, after the Navy had turned him down, and commissioned him in the Army Medical Corps. It says the OSS Maritime Unit's swimmers tested the harbour defences at Guantanamo Bay on 21 July 1944, in what was called Operation Cincinnati, without being detected. Wikipedia says the US Navy calls Lambertsen the "Father of the Frogmen".

Diving medicine

The University of Pennsylvania's hyperbaric medicine history page describes him as a primary inventor of SCUBA and says he founded its Division of Undersea and Hyperbaric Medicine, under the Institute for Environmental Medicine, in 1968.

His role in founding the Undersea Medical Society, now the Undersea and Hyperbaric Medical Society (UHMS), is described in more than one way:

• The NAE tribute says Lambertsen founded the society in 1967 to 1968.
• Wikipedia, seen as a search summary, says six US Navy diving and submarine medical officers founded it, gives a charter date of 10 April 1967, and says Lambertsen wrote its constitution.
• Another account, from a hyperbaric medicine publisher's blog seen only as a search summary, says six people (five physicians and one PhD) conceived the society at the 1966 Aerospace Medical Association meeting. We could not confirm it.

Where the word SCUBA came from

The versions below all connect the acronym, for self-contained underwater breathing apparatus, with Lambertsen, and three of the four place it in 1952. They differ on how it arose and on whether he coined it himself.

Wikipedia's article on Lambertsen does not itself say that he coined the word, and it notes that present-day use of "scuba" is largely attributed to the Cousteau-Gagnan open-circuit invention. Dictionary.com dates the word to 1950 to 1955 and gives it as an acronym of self-contained underwater breathing apparatus. According to Wikipedia, "SCUBA", gradually written in lower case as "scuba", came to mean any self-contained underwater breathing apparatus, first in the United States, and later the activity itself.

Wikipedia's Lambertsen article also points out that the word was first applied to Lambertsen's closed-circuit rebreather, not to the open-circuit Aqua-Lung that most people now picture. No primary dictionary entry, 1952 patent or NAS paper was located during research, so the exact first use remains unconfirmed.

Lambertsen also appears in the history of enriched air: a 1992 magazine article credits him with proposing it in 1943. That account, and how enriched air later reached sport divers, is on nitrox comes to recreational diving.