The configuration of V-4, V-5, and V-6 resulted from an evolving strategic concept that increasingly emphasized the possibility of a naval war with Japan in the far western Pacific.
[8] The auxiliary engines were for charging batteries or for increased surface speed via a diesel-electric system providing power to the main electric motors.
Welding was used to join the vertical keel plates, and also in other non-critical areas like the superstructure, piping brackets, and support framing.
Reassigned to SubDiv 13 at San Diego, California, 1935–1938, then re-homeported at Pearl Harbor, she maintained a regular schedule of training activities and fleet exercises and problems throughout the decade.
In July 1941, she entered the Mare Island Naval Shipyard for modernization – radio equipment, external torpedo tubes (two bow and two stern-firing in the gun deck),[11] re-engining (with four Winton diesels),[14] and air conditioning – until the following spring.
One failed to run, two ran erratically, and the fourth was a dud (a familiar problem for the Mark XIV), impacting amidships and breaking in half.
Nautilus departed Hawaiian waters for her second war patrol, a special troop transport mission of three weeks duration, 8 August.
The remainder, less nine who were later captured and executed, discovered there were no Japanese left to fight and crossed to the lagoon side, whence they headed for the submarine after nightfall on 18 August.
On her third war patrol, from 15 September to 5 November, Nautilus returned to Japanese waters to join the submarine blockade chain stretched from the Kurile Islands to the Nansei Shoto.
Moving to a quieter area, with less aerial activity, she continued her patrol until 24 October when she sank Kenun Maru, then headed for home without sighting enemy planes.
On 27 April, she put into Dutch Harbor, Alaska, and commenced instructing the 7th Infantry Division Provisional Scout Battalion in amphibious landings.
Overhaul at Mare Island occupied most of the summer and on 16 September Nautilus left Pearl Harbor to spend her sixth war patrol conducting photo-reconnaissance of the Gilbert Islands, concentrating on Tarawa, Kuma, Butaritari, Abemama, and Makin, all of which had been reinforced, particularly Tarawa, since the sub's 1942 excursion into those waters.
The information, including continuous panoramic pictures of the coastlines and chart corrections, which she brought back to Pearl Harbor on 17 October, proved among the most useful intelligence gathered of the area prior to the invasion of Tarawa.
She returned to Tarawa 18 November to obtain last-minute information on weather and surf conditions, landing hazards and the results of recent bombardments.
At 21:59 on 19 November, mistaking her for a Japanese submarine, the destroyer USS Ringgold (DD-500) fired at her while she was off Maiana in the Gilbert Islands at 01°05′N 173°03′E / 1.083°N 173.050°E / 1.083; 173.050, hitting her at the base of her conning tower with a five-inch (127 mm) shell which did not explode but damaged the main induction valve.
At midnight 20–21 November, Nautilus lay 3,000 yards (2,700 m) off an island in the Abemama Atoll, Kenna to discharge her passengers.
On the afternoon of 22 November, Nautilus provided fire support to bring the tiny (25-man) enemy garrison out of their bunkers.
By the time the main assault force arrived on 26 November, Abemama had been secured and preparations to turn it into an air base for the Marshall Islands campaign had begun.
On 26 April, Nautilus sailed for Brisbane, whence she departed 29 May to begin a series of special missions in support of guerrilla and reconnaissance activities in the Philippines.
On her 12th, 13th and 14th patrols, she returned to the central Philippines, landed personnel and supplies at various points on Mindanao and Luzon, and carried evacuees to Australia.
With the blowing of her main ballast tanks she was finally able to get off the reef within three and a half hours, despite the receding tide, and clear the area by dawn.
Nautilus's six-inch (152 mm) guns, however, scored 55 hits, and her report states, "It is doubtful that any equipment in Darter at 11:30 this date would be of any value to Japan – except as scrap."
Decommissioned with a bottle of champagne over the forward 6 inch (152 mm) gun on 30 June, she was stricken from the Naval Vessel Register 25 July and sold 16 November, to the North American Smelting Company of Philadelphia, Pennsylvania, for scrapping.
Season 2, Episode 26 of the American television series The Silent Service, first broadcast in 1958, dramatizes the Teop Harbor rescue of 24 December 1942.