USS S-21

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USS S-21 (SS-126) was an S-18-class submarine, also referred to as an S-1-class or "Holland"-type, of the United States Navy, in commission from 1921 to 1922 and from 1923 to 1942. In 1928, she made the first gravimetric measurements ever made aboard a US ship at sea. Prior to World War II, she operated in the Atlantic Ocean, Caribbean Sea, and Pacific Ocean, and after the United States entered the war, she operated off Panama. She was transferred to the Royal Navy as P.553 from 1942 to 1944.

Design

The S-18-class had a length of overall, a beam of Template:Cvt, and a mean draft of Template:Cvt. They displaced on the surface and Template:Cvt submerged. All S-class submarines had a crew of 4 officers and 34 enlisted men, when first commissioned. They had a diving depth of Template:Cvt.

For surface running, the S-18-class were powered by two NELSECO diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a Ridgway Dynamo & Engine Company electric motor. They could reach on the surface and Template:Cvt underwater.

The boats were armed with four torpedo tubes in the bow. They carried eight reloads, for a total of twelve torpedoes. The S-18-class submarines were also armed with a single [[4"/50 caliber gun|Template:Cvt/50 caliber]] deck gun.

Construction

S-21Template:'s keel was laid down on 19 December 1918, by the Bethlehem Shipbuilding Corporation's Fore River Shipyard, in Quincy, Massachusetts. She was launched on 18 August 1920, sponsored by Mrs Gladys Baxter, and commissioned on 24 August 1921.

Service history

1921–1928

Following operations from New London, Connecticut, S-21 was decommissioned and returned to her builder, on 31 March 1922. After she was reacquired by the Navy, S-21 recommissioned at Groton, Connecticut, on 14 September 1923.

S-21 then operated off the Northeastern Coast, of the United States. She visited the Panama Canal, Saint Thomas, in the US Virgin Islands, and Trinidad, between January and April 1924. Departing New London, on 25 November 1924, she visited the Territory of Hawaii, from 27 April to 25 May 1925, before returning to New London, in July 1925. Following duty in the Panama Canal area, from February through April 1926, she visited Kingston, Jamaica, from 20 to 28 March 1927. After operating in the Panama Canal area, from February into April 1928.

First US gravity measurements at sea

A Royal Navy submarine had made the first gravity measurements at sea in 1926, and the Carnegie Institution for Science subsequently proposed that the United States take such measurements in the Caribbean Sea, using a gravimeter designed by Dr. Felix Andries Vening Meinesz. Such measurements required the stability and lack of motion only attainable at sea if taken aboard a submerged submarine. S-21 was selected for the expedition, which was arranged with assistance from the United States National Academy of Sciences, the United States Coast and Geodetic Survey, the United States Naval Observatory, which provided special chronometers necessary for the gravimetric observations, and the United States Navy Hydrographic Office. Meinesz accompanied the expedition, with Elmer B. Collins, aboard S-21, to represent the US Navy Hydrographic Office, and two Eagle-class patrol craft, Eagle 35 and Eagle 58, serving as tenders.

The expedition set out from Hampton Roads, Virginia, on 4 October 1928, and followed a route that took it to Key West, Florida; Galveston, Texas; Guantanamo Bay, Cuba; the US Virgin Islands; and Puerto Rico, with a return to Hampton Roads, on 30 November 1928. The first of 49 gravity measurement stations that S-21 occupied was at . The gravity measurements were accompanied by a sonic depth sounding with results published on a chart produced by the US Navy Hydrographic Office. The gravity measurements were used in determining the shape of the Earth, and of particular interest were significant negative gravity anomalies the expedition detected.

The results of the expedition, particularly the negative anomalies, created interest in a second US gravimetric expedition at sea, resulting in the Navy-Princeton gravity expedition to the West Indies, in 1932, using the submarine , and a third measurement effort in 1936–1937, the Gravimetric Survey Expedition, using the submarine .

1929–1941

After returning from her gravimetric expedition, S-21 resumed operations from New London, along the Northeast Coast of the United States. She also served in the Panama Canal area, from March to April 1929 and again from January through February 1930.

Departing New London, on 22 October 1930, S-21 transited via the Panama Canal, and California, to Pearl Harbor, in Hawaii, arriving there on 7 December 1930. From 1931 into 1938, S-21 operated from Pearl Harbor, with the period 18 November 1932 to 24 January 1934, spent in reserve.

Departing Pearl Harbor on 15 October 1938, S-21 transited via California and the Panama Canal, to the Philadelphia Navy Base, arriving on 11 December 1938. Following overhaul, she arrived at New London, on 25 March 1939. She remained at New London, with a partial crew, from 1 June 1939 until 1 September 1940, when she returned to full commission with a full crew.

World War II

The United States entered World War II, with the Japanese attack on Pearl Harbor, on 7 December 1941. On 9 December 1941, S-21 got underway from New London, bound for the Panama Canal Zone. Arriving on 19 December 1941, she conducted defensive war patrols in the Pacific Ocean approaches to the Panama Canal, through May 1942, although her second such patrol, scheduled for 24 January to 7 February 1942, was cancelled to allow her to participate in search and rescue operations for the submarine , which had sunk on the night of 24 January, after the submarine chaser accidentally rammed her when the vessels were operating without navigation lights to avoid detection by the enemy.

In June 1942, S-21 returned to New London. On 14 September, she was decommissioned and was transferred to the United Kingdom.

Royal Navy

As HMS P. 553, she served in the Royal Navy, until returned to the US Navy, at Philadelphia, on 11 July 1944.

Disposal

After her return, the US Navy used S-21 as a target. She was sunk in of water in the Atlantic Ocean off Cape Elizabeth, Maine, on 23 March 1945.

Bibliography

• Public Domain This article incorporates text from this source, which is in the public domain.

External links

• Naval Oceanographic Office - Historical Timeline
• Plate tectonics: an insider's history of the modern theory of the Earth, by Naomi Oreskes, Homer Eugene LeGrand
• Eagle Class Patrol Vessel (PE) description