Several snorkel systems or snorkel-like systems were installed on board US submarines. Simon Lake used an engine exhaust system that utilized a pipe extending above the main deck aft. The Alligator (1862) had an ‘air tube’ to allow air to be drawn into the boat while it was submerged at a shallow depth. The CSS Hunley had a similar air tube system. John Holland's Plunger (1898) was to have a coiled hose system which had a float to permit air to be drawn in from a deeper depth than either the Alligator or Hunley.
The snorkel system design and testing program for what can be called the ‘standard submarine snorkel’ is summarized below:
Portsmouth Naval Shipyard (Kittery, ME) performed the design work on a snorkel system as an independent design using captured blueprints and a snorkel mast system captured in Toulon, France. CNO directed, on 20 January 1945, that an accelerated design and build program be instituted and an R-Class submarine be selected for experimentation (this is equivalent to the Engineering Development Model in today's language). [CNO letter of 26 January 1945].
The R-6 was selected and the snorkel was fitted in Portsmouth during the period 10 April to 20 May 1945. The system was tested and provided information on the effects of the snorkel on personnel and equipment. Piping was installed on the main deck for simplicity and the snorkel mast was fixed in an upright position. R-6 took the system to Florida in August 1945 for testing in an ASW setting. The boat operated for three days in southern waters (out of Ft. Lauderdale) during the period 3 to 25 August 1945 and three major engine casualties were reported. However it is unknown whether these were due to the snorkel or were due to other factors such as age and maintenance. The system's components were removed prior to the decommissioning of the boat in September 1945.
The next testing phase was held aboard the USS Sirago (SS-485) [Note: this is not the Odax (SS-484)] immediately after her commissioning (Commissioning was on 10 September 1945). Preliminary tests took place at Portsmouth during the period 11 to 13 September 1945. The tests were to determine if the design was adequate and the effect of snorkeling on diesel engines and personnel.
{Sirago had four Fairbanks Morse 10 cylinder D38 8-1/8 engines numbered 848587 through 848590. Only one engine was fitted with the exhaust ducting for testing, number 848588}
The tests on 11 September tested the machinery, calibration of the measurement equipment and personnel orientation. Engine standardization runs were carried out on the 12th. These included runs at snorkel depth (alongside) to determine the effect of the varying back pressure on engine speed and loading. On the 13th runs were made which simulated wave action on the (float type) head valve cycling. The system was dismantled starting on 17 September.
Electric Boat Company had been designing their own snorkel system. They asked the Navy to provide the data that had been compiled during the testing of R-6 and Sirago. The company proposed on 12 June 1945 that a system be put aboard either Clamagore (SS-343) or Cobbler (SS-344). The Navy Inspector of Shipbuilding selected Clamagore. However, in Electric Boat's opinion the Clamagore was too close to completion and pushed for the Cobbler in a test plan dated 19 June 1945. BuShips approved the plan on 4 July 1945. The test was not a full snorkel system but a pressure variation test using just the power operated head valve. The head valve was to be fastened to a plate which was then mounted on the after engine room hatch. However, in the builder's underway trials (prior to the head valve testing) the lube oil systems of the four main engines had problems and the testing was delayed. Electric Boat withdrew from further snorkel design for fleet submarines.
The Irex (SS-482) received the first ‘full up’ snorkel system in Portsmouth Naval Shipyard starting in December 1946. The system was evaluated in extensive testing during the period July 1947 to February 1948. She was then the first US submarine to become operational with a snorkel.
Extracted from Warship International, Volume 41, Numbers 1 and 4. “Now Hear This” column by Mr. C. Wright. Primary research done by Mr. Mark C. Jones and Mr. C. Wright. Edited for content by Mr. Jim Christley. Primary source material can be found in BuShips General Correspondence Files C-SS/S41-5, C-SS/S68, CSS83 and SS83 in the National Archives.