The Mandan Victory was placed into service by the War Shipping Administration's Emergency Shipbuilding program under cognizance of the U.S. Maritime Commission.
Jack J. Pendleton, the Victory ship received miscellaneous alterations, including the addition of radar and the enlargement of her hatches, during the summer; and, in the fall, she commenced 18 months of operations under the Army Transportation Service.
In late June, as the war in Korea broke out, she completed her second round trip to Japan as an MSTS ship and, for the next two years, was employed in moving combat cargoes westward.
In 1958, she was commended for rescuing the entire crew of a large Japanese fishing vessel which had gone down in the Pacific; and, in the same year, she again added northern ports in the Aleutians to her delivery points.
In 1959, after calls at ports on the Indian Ocean, the Arabian Sea, and the Gulf of Aden, the ship transited the Suez Canal to take on and deliver cargo in the Mediterranean.
During October and November, she put into ports on the Indian subcontinent, in southeast Asia, on the island of Taiwan, and on the Korean peninsula.
In early December, she was in Japan; and, on the 29th, she arrived at Seattle, Washington, whence, with the new year 1960, she returned to San Francisco to resume transpacific operations.
Later in that year, the Victory ship interrupted her more routine schedule to bring the Navy's bathyscaph, Trieste, back to San Diego, California, after the research vessel had set a record dive of 35,800 feet in the Mariana Trench.
The ship planned to turn East once it cleared Triton Island, not knowing that wind and waves had set the Pendleton to the north.
Jack J. Pendleton ran aground on a reef at Triton Island at 17 1/2 knots, very early in the morning, so smoothly that the Captain was not disturbed in his cabin.
After many attempts, including an unsuccessful attempt by the embarked UDT/Seals (Underwater Demolition Team)from the Deliver to blow a hole in the reef surrounding Triton Island to facilitate the salvage operation using LCU-8s instead of the CH-46 and CH-53 helicopters from Mount Vernon and Mount Hood, members of all five ships were sent aboard the Sgt Jack Pendleton to salvage whatever was felt could be used for the rest of their deployments.
It was determined that leaving a large ship loaded with unstable ammunition and grounded on an island claimed by multiple countries (some friendly, some not) was not a diplomatic thing to do.
An EOD team from the Mount Hood was sent aboard to remove any masts that would prevent the helicopter from reaching the hold located amidships.
In a well-orchestrated set of explosions, the main mast amidships was severed at its base, and then 1/2 a second later blown over the port side of the ship.
As the storm subsided, Beaufort and Reclaimerhooked their steel cables and beach gear to the aft section of Sgt.
During the same time, China sent a message stating it owned the island and to stop all procedures and depart the island; North Vietnam also stated it owned the coral reef and to make haste out of the area or it would send a warship to engage the Navy ships, both dispatches were taken seriously, however, neither country possessed an operational naval vessel nearby.
Beaufort Hull Technicians shored its bulkhead with wood and steel, until it could get back to port for major repairs.