USS Dolphin (SF-10/SC-3/SS-169), a submarine and one of the "V-boats", was the sixth ship of the United States Navy to be named for that aquatic mammal.

[3][4][6] The auxiliary engines were for charging batteries or for increased surface speed via a diesel-electric system providing power to the main electric motors.

[7] The designer of the Dolphin, Andrew McKee, was concerned about weight growth and so he made the decision to trim off a portion of the standing flange on the I-beams used in hull construction, leaving them looking somewhat like the number 1.

[8] Dolphin departed Portsmouth, New Hampshire on 24 October 1932 for San Diego, California, arriving on 3 December to report to Submarine Division 12 (SubDiv 12).

In 1933, Dolphin tested an unusual feature for submarines of having a waterproof motor boat, stored in a compartment aft of the sail, which could be brought out when needed.

She cruised on the west coast with occasional voyages to Pearl Harbor, Alaska, and the Panama Canal Zone for exercises and fleet problems.

Located at Pearl Harbor on 7 December 1941, Dolphin took the attacking enemy planes under fire, and then left for a patrol in search of Japanese submarines in the Hawaiian Islands.

Dolphin departed from Pearl Harbor on 24 December 1941 on her first war patrol, during which she reconnoitered in the Marshall Islands in preparation for later air strikes.