John P. Cromwell

Captain John Philip Cromwell (September 11, 1901 – November 19, 1943) was the most senior submariner awarded the Medal of Honor in World War II and one of the three submarine officers who received it posthumously. In some ways similar to his fellow honoree, Howard Gilmore, Cromwell consciously chose to sacrifice his own life to safeguard the lives of others, in a combat action which took place in November 1943.

Early life and career Cromwell was born in Henry, Illinois, on September 11, 1901. Appointed to the U.S. Naval Academy in 1920, he graduated in June 1924 and served initially in the battleship USS Maryland school and was assigned to during 1927–29. He next had three year's diesel engineering instruction, followed by further tours of duty in submarines.

Lieutenant Cromwell commanded in 1936–37, then served on the staff of Commander Submarine Division 4. He was promoted to the rank of lieutenant commander in 1939 and spent two years in Washington, D.C., with the Bureau of Engineering and Bureau of Ships. In May 1941, he became engineer officer for the Pacific Fleet submarine force. and knew a lot more about ULTRA – and its source – than anyone else on . It was Cromwell's first war patrol also. The gun crew died almost instantly from shrapnel. The senior ship's officer surviving, a reserve lieutenant, ordered the boat scuttled and the crew to abandon ship. went down with as she sank. The 41 survivors were taken to Truk and interrogated for ten days by Japanese intelligence officers. The group was divided in half for transport back to Japan on two escort carriers – 21 on Chuyo and 20 on . Those on Unyo arrived in Japan in early December and spent the rest of the war working in the Ashio copper mines, after which they were repatriated to tell their story.

Other honors In 1954, the destroyer escort was named in his honor.

Cromwell Hall, the Navy's Submarine Learning Center at the submarine base in Groton, Connecticut, was also named for him.