[Daniel Prates]

Not anybody might know this (i didn't), but RSRD was based on a best-selling novel. The plot is somewhat different. This is how wikipedia summons it up:

"Beach's bestselling novel of submarine warfare begins soon before the attack on Pearl Harbor. The story is ostensibly a Navy tape recording about events, as related by Richardson, resulting in his award of the Medal of Honor. An American submarine captain, Richardson is given a new boat with orders to destroy Japanese shipping in the Pacific Ocean. His executive officer and former best friend, Jim Bledsoe, is resentful because Richardson is forced to fail him after Bledsoe acts recklessly during his test for qualification for command, nearly sinking their boat. Adding to the difficulties between them, Richardson is secretly enamoured of Bledsoe's fiancee, Laura, who despises him for ruining Bledsoe's chance.
During their first war patrol in the USS Walrus, they encounter the Japanese destroyer so-called the Akikaze, whose skipper, Captain Tateo Nakame, is nicknamed "Bungo Pete" and is responsible for a series of sinkings of American submarines in the Bungo Strait, including the USS Octopus, on which Richardson served, and the USS Nerka, which had been commanded by a close friend. Richardson, wounded in a subsequent encounter with Pete, remains at Pearl Harbor while Bledsoe commands the Walrus for three war patrols. Bledsoe establishes a reputation for himself as an aggressive skipper with a good rate of sinkings. Between patrols, Bledsoe has an extramarital affair at Pearl Harbor, causing Richardson some anguish for Laura's sake. During the last of the patrols, however, Bungo Pete sinks the Walrus.
During his stint ashore, Richardson works on solving reliability problems with American torpedoes. When the news of the loss of Bledsoe and the Walrus arrives, Richardson convinces his superiors to let him return to the Bungo Strait and hunt Bungo Pete in a new submarine, USS Eel. A great battle ensues between the Eel and Bungo Pete's special anti-submarine warfare group, which consists of the Akikaze, a Q-ship, and a Japanese submarine. After sinking all three vessels, Richardson realizes that Bungo Pete and his skilled specialists will be rescued to resume their hunting, and rams the lifeboats intentionally to kill them.
Soon after the destruction of Bungo Pete, the Eel is detailed to lifeguard duty off Guam, where Richardson's actions saving three aviators earns him the Medal of Honor. After the war he returns home, expressing his hope to begin a relationship with Laura Bledsoe."