Question for historians

[Pilot_76]

Did the USN actually employ subs in the Atlantic? I know for coastal defense against Uboats but deep ocean ops I mean...

How about the Jap subs? How did they do? I know I can look into wikis but I'd like an answer here first. Italy as well...

[Aktungbby]

Originally Posted by Pilot_76

Did the USN actually employ subs in the Atlantic? I know for coastal defense against Uboats but deep ocean ops I mean...

How about the Jap subs? How did they do? I know I can look into wikis but I'd like an answer here first. Italy as well...

Some actually died

Of 52 submarines lost by the U.S. Navy during World War II, two were sunk in the Atlantic Ocean. During a training exercise off Key West, Florida, on June 12, 1943, the old submarine R-12 (SS-89) foundered while diving; its commander, another officer and three crewmen swept off the bridge were rescued, the other 42 men went down with the sub. On October 6, 1943, Dorado (SS-248), having completed its shakedown cruise (during which artist Thomas Hart Benton was aboard to paint aspects of life aboard a typical Gato class sub), left New London, Connecticut, for the Panama Canal Zone. It never arrived. While it was en route, Martin PBM Mariner flying boats attacked suspected Unterseeboot sightings, believed to have been U-518 and U-214. The latter vessel logged having survived the attack and subsequently laid 15 mines five miles off Colón, Panama, on October 8. It is now believed that Dorado ran into one of those mines on October 12 or 14, and was lost with all hands.

Additionally:

U.S. Submarine Operations in the Atlantic during World War II

While the extraordinary success of U.S. submarines against Japanese shipping in the Pacific completely overshadowed the achievements of their counterparts in the Atlantic, LANTFLT boats nonetheless made a major contribution to winning the war in Europe. In February 1941, shortly after the Navy reorganization that created the Atlantic, Pacific, and Asiatic Fleets, RADM Richard Edwards became Commander Submarines, Atlantic, the forerunner of COMSUBLANT. Originally comprising only B, O, R, and S-class boats, of which only the last were truly oceangoing, Submarines Atlantic prepared for war with a series of contingency plans that led eventually to basing submarines in Key West, St. Thomas (U.S.Virgin Islands), Bermuda, Coco Solo (Panama), and Argentia (Newfoundland). Additionally, all East Coast new-construction boats - the great majority - honed their skills for the Pacific war on shakedown and training cruises in the LANTFLT area. During June 1941, with the rising threat of the German U-boat campaign against Britain, U.S. submarines began defensive patrols in both the Atlantic and Caribbean, with particular emphasis on protecting shipping lanes off the East Coast and through the Panama Canal. After Pearl Harbor brought the United States into the war, U.S. boats established an intermittent patrol line from Bermuda to Nantucket, but despite regular sightings and several brief skirmishes with German U-boats, there were no kills or losses.
For operations in European waters, Submarine Squadron 50 was established at New London in September 1942. Comprising six new Gato-class boats and the submarine tender USS Beaver (AS-5), it departed in October for a base at Rosneath on the west coast of Scotland and saw its first major action in support of Operation TORCH, the Allied invasion of Vichy-controlled French North Africa. Five SUBRON 50 boats served in the invasion force, performing reconnaissance off the landing sites in Morocco, establishing navigation references for the amphibious assault, patrolling against possible Vichy French resistance, and even putting U.S. Army scouts ashore in advance of the main landings on 8 November 1942. On D-Day, USS Herring (SS-233) sank a 5,700-ton cargo ship, Ville de Havre, but French opposition to the invasion was only token, and the North African campaign was off to a successful beginning.
Following TORCH, SUBRON 50 passed under Royal Navy operational control and patrolled the Bay of Biscay to interdict German blockade-runners attempting to run war supplies through Axis-leaning Spain. In this role, they inflicted significant damage - and even a few losses - on both small freighters and several German escorts. Moreover, in March 1943, Herring scored a probable kill on a 517-ton U-boat. In April 1943, the squadron's patrol responsibilities were shifted to the Norway-Iceland area, but lack of targets in the Atlantic soon motivated a decision to return SUBRON 50 to the United States and re-allocate its submarines to the Pacific.
This was indicative of the turning tide in the Battle of the Atlantic, and although German U-boats remained a recurring threat until late in the war, improved sensors and weapons, convoying, increasingly effective combined-arms ASW prosecutions, and a significant cryptologic advantage drove them back. Because U.S. submarines played little part in ASW operations during the final phases of the European conflict, the primary role that remained for LANTFLT submarines was to support the training of escort ships and patrol aircraft, largely from a training base in Bermuda.
Three submarines were lost in the Atlantic area during World War Two. In January 1942, USS S-26 (SS-131) went down in the Gulf of Panama after a collision with the patrol craft PC-460, and in June 1943, R-12 (SS-89) was lost near Key West due to accidental flooding. Then, during October 1943, USS Dorado (SS-248) disappeared with all hands during a transit between New London and Panama, and her fate remains unknown to this day. There is some evidence that she was either depth-charged by one of our own aircraft or torpedoed by a German U-boat that had been operating in the same vicinity near Cuba.

Thanks for asking I've really never looked into Atlantic US operations as the focus is usually in the Pacific.