Lambertsen Amphibious Respiratory Unit


The Lambertsen Amphibious Respiratory Unit (LARU) is an early model of closed circuit oxygen rebreather used by military frogmen. Christian J. Lambertsen designed a series of them in the US in 1940 (patent filing date: 16 Dec 1940) and in 1944 (issue date: 2 May 1944).[1]


The LARU is what the initials SCUBA (Self-Contained Underwater Breathing Apparatus) originally meant; Lambertsen changed his invention's name to SCUBA in 1952;[2] but later "SCUBA", gradually changing to "scuba", came to mean (first in the USA) any self-contained underwater breathing apparatus. (Modern diving regulator technology was invented by Émile Gagnan and Jacques-Yves Cousteau in 1943 and was not related to rebreathers; nowadays the word SCUBA is largely used to mean Gagnan's and Cousteau's invention and its derivatives.)


Lambertsen designed the LARU while a medical student and demonstrated the LARU to the Office of Strategic Services (OSS) (after already being rejected by the U.S. Navy) in a pool at the Shoreham Hotel in Washington D.C. in 1942[3][4] The OSS "Operational Swimmer Group" was formed and Lambertsen's responsibilities included training and developing methods of combining self-contained diving and swimmer delivery including the LARU.[5][6]


  • Two large lengthways backpack mounted cylinders under a hard metal cover: the right cylinder is high pressure oxygen and the left is the cylindrical absorbent canister.
  • Fullface mask with two small viewports like an old-type gasmask
  • Two counterlungs, one on each shoulder.
  • A breathing conduit of 4 lengths of large-bore corrugated breathing tubes in a loop: from the mask to one of the breathing bags to the canister to the other breathing bag to the mask.
  • Its harness is a strong cloth jacket that enclosed the diver's chest.
  • Mid front, a long zipped pocket: the diagrams do not show whether it was for kit or for diving weights.

Many diving rebreathers are descended from it. However, there were earlier underwater uses of rebreathers:

See also

  • Rebreather – Portable apparatus to recycle breathing gas


  1. ^ Lambertsen's patent in Google Patents
  2. ^ See Lambertsen's homage by the website
  3. ^ Shapiro, T. Rees (February 19, 2011). "Christian J. Lambertsen, OSS officer who created early scuba device, dies at 93". The Washington Post. Retrieved 2013-05-16.
  4. ^ staff (2013-10-30). "'America's first frogman' dies in Bend at 95". KTVZ. Archived from the original on 2013-11-03. Retrieved 2013-11-02.
  5. ^ Vann RD (2004). "Lambertsen and O2: beginnings of operational physiology". Undersea Hyperb Med. 31 (1): 21–31. PMID 15233157. Retrieved 2013-05-16.
  6. ^ Butler FK (2004). "Closed-circuit oxygen diving in the U.S. Navy". Undersea Hyperb Med. 31 (1): 3–20. PMID 15233156. Retrieved 2013-05-16.

External links

  • A long biography about him, and about the rebreather that he designed
  • Images of his rebreather
  • Image of Lambertsen rebreather's fullface mask, 1944, with eyeholes
  • Front view of frogman swimming with Lambertsen rebreather, 1944
  • Lambertsen rebreather with mouthpiece on neck strap, and eyes-and-nose mask, 1944
  • Underwater Demolition Team Operations U.S. Navy video demonstrating the Lambertsen rebreather National Archives #76869