USS Chaumont, one of twelve 13,400-ton (displacement) Hog Island Type B (Design 1024) transports built for the U. S. Shipping Board at Hog Island, Pennsylvania, was laid down in November 1918 as the Shipping Board's Shope, launched in March 1920 as the U.S. Army's Chaumont, and completed a few months later. Excess to Army needs, she was transferred to the Navy and commissioned in November 1921. From her home port at San Francisco, Chaumont commenced a career of trans-Pacific troop service that initially consisted of voyages between California and Manila via Honolulu. Two or three voyages in 1925-26 took her to Shanghai instead of Manila, and she continued to stop at Shanghai at least once during most subsequent years. In August 1926 she sailed from San Francisco through the Panama Canal to Annapolis. The return trip took her to Norfolk, where she was drydocked for routine maintenance, and then to Guantanamo. Such voyages between the East and West Coasts also became near-annual events.

Chaumont's voyages to Shanghai provided important assistance to U.S. Far Eastern diplomacy during the 1920s and 1930s by supporting the Marine Corps units deployed to the International Settlement in that city to protect U.S. nationals there. At the end of January 1932 Japanese forces in the Settlement attacked nearby Chinese forces, leading to intensive fighting in the city. Chaumont was in Manila at the time, and on 31 January the Navy Department ordered her to embark the 1,000 men of the Army's 31st Infantry Regiment and sail for Shanghai. Responding rapidly, Chaumont cleared Manila with the troops on board on 2 February and arrived at Shanghai on the 5th. Five years later, in mid-September 1937, Chaumont rushed the 6th Marine Regiment to Shanghai to reinforce the 4th Regiment that was protecting the Settlement during the all-out Japanese effort to seize the city from tenacious Chinese defenders. Chaumont suffered two mishaps during her China service in 1936-37, a week-long period aground at Chingwangtao and a collision at Shanghai with the Italian cruiser Raimondo Montecuccoli.

When the Japanese attacked Pearl Harbor, Chaumont was on one of her regular voyages from Hawaii to Manila. She was diverted to Darwin, Australia, and then sent back to the West Coast. After two runs to Pearl Harbor, the now elderly transport was assigned to service between Seattle and Alaska, bringing men and supplies to assist in the defense of the Aleutians. Selected in March 1943 for conversion to a hospital ship, Chaumont was decommissioned in August at Seattle. She returned to active service in March 1944 as Samaritan (AH-10) and retained that name and designation until she was sold for scrapping in early 1948.

One of her most important contributions, when in the Pacific, was aiding in the collection of meteorological information used by the Weather Map Service of the Asiatic Fleet. She also carried military supplies, Marine expeditionary forces, sailors and their dependents, and occasionally members of congressional committees on inspection tours, calling at ports from Shanghai to Bermuda.

After an abortive attempt at across-the-board modernization in the early Depression years, virtually all OP-20-G's attempts to increase manpower and improve equipment during the 1930s were directed toward the Pacific basin where the Japanese threat was seen as paramount. In 1937, OP-20-G opened the long anticipated major research unit in Hawaii with the task of supporting Washington's efforts. [81] Lieutenant Commander Thomas Dyer was detached from fleet duty and assigned to COM-14 as a cryptanalyst. His duties were to establish a decrypting unit and undertake research work on "M1 Orange Naval Cryptographic System." [82] Message files for 1935, 1936 and 1937 were supplied by OP-20-G and sent to Dyer via the USS Chaumont. COM-16 sent copies of all traffic, including messages intercepted by Stations A, B, and C to Dyer, and Washington mentioned that IBM equipment would be forthcoming at once. At the outset, when not occupied by other duties assigned by COM-14, Dyer, who was not a Japanese linguist, single-handedly attempted to recover all keys as they appeared. He naturally forwarded all solutions to Washington for translation. In 1939, when the M1 system had been exhausted, Dyer was assigned cryptanalytic responsibility for the Japanese Navy's Flag Officers Code. Lieutenant Joseph Richardson appeared the following July as language officer.

[81] Both Laurence Safford and A/CNO RADM Royal E. Ingersoll indicated (Pearl Harbor Attack Hearings Before the joint Committee on the Investigation of the Pearl Harbor Attack, Congress of the United States, 79th Congress, hereafter PHA, part 26, 388 and part 9, 4241, respectively) in their testimonies that they believed Hawaii was responsible to CINPCAC; Safford in his testimony to the Hart inquiry, Ingersoll while being cross-examined by Kimmel during the congressional investigation. it was Safford, of course, who in 1937 opened the office, assigned Dyer and others to COM-14, and allocated all cryptanalytic tasks until 1942.

[82] Memorandum from CNO to COM-14, 21 August 1937, "Cryptanalysis, Orange M1 System" Series III.H.17, CCH History Collection (classified). The M-1 was a Kana cipher machine used by the Japanese navy from July 1933 for about four years. It is described in RIP28. Jack S. Holtwick, A Guide to Foreign Cryptographic Systems: U.S. Navy Short Titles, Cover Names, and Nicknames, 14 June 1971. NSA Cryptologic Archival Holding Area (classified).

29 Nov 1941 departed Pearl Harbor for Manila.

Diverted 7 Dec 1941 to Suva, Fiji, Brisbane, and Darwin.

Landed at Darwin 5 Jan 1942.

Returned to Bisbane at end of Jan 1942, then to Sydney, Wellington, Balboa (Canal Zone), and San Francisco 29 Mar.

Made two runs San Francisco to Pearl Harbor and return (8 May, 24 Jun) then several Seattle to Alaska and return (including various Alaskan ports 16 Jul, Seward 10 Aug, various ports 12 Sep, Kodiak 18 Sep).

Decommissioned 28 Aug 1943, reclassified 2 Sep as hospital ship USS Samaritan (AH-10), recommissioned 1 Mar 1944.

After 25 Mar 1944 made two runs San Francisco to Pearl Harbor and return.

Returned to Pearl 11 May, continued to Kwajalein, treated Saipan casualties 17 Jun to 1 Jul.

Sailed to Saipan, on 8 Jul departed for Noumea, New Caledonia, and returned to Saipan 1 Aug.

Evacuated patients from Guam to Guadalcanal, and from Peleliu to Russell Islands, Aug and Sep 1944.

Sustained major hull damage running aground on Tannu Reef at 0325 24 Sep 1944 en route to the Russell Islands.

Brief overhaul at Espiritu Santo, served as base hospital at Ulithi until sailing for Iwo Jima 16 Feb 1945.

Arrived at Iwo Jima 20 Feb, evacuated 606 patients to Saipan.

Returned to Saipan 25 Feb, made two runs to Guam.

Arrived Ulithi 2 Apr

Left Ulithi for Okinawa 9 Apr, arriving 13 Apr.

Made several evacuation runs from Okinawa to Saipan until sailing for Pearl 1 Jul.

Took patients on board, sailed to San Francisco, returned to Pearl 10 Sep, then to Sasebo.

Supported occupation forces until 15 Mar 1946.

Returned to San Francisco 23 Apr 1946, decommissioned 25 Jun 1946.