Nautilus being towed into Portsmouth, England

Wilkins's Nautilus was not a state of the art sunmarine, nor was she specially built for the expedition. In the 1930s, most of the world's submarines were dedicated to naval service, and most navies were reluctant to part with the few ships they had. In the wake of the London Naval Treaty, however, the United States was willing to part with a pre-World War I O-class submarine, the O-12 (hull number SS-73). Built in 1916 at the Lake Torpedo Boat Co., in Bridgeport, Connecticut, she was 175 feet long, with a beam of 16 feet 7 inches, and a draft of 13 feet 11 inches. Her top speed was 14 knots surfaced, and 11 knots submerged. Ironically, given the fate of the mission, Wilkins had been offered the O-13, but turned it down, feeling that the ship's designation was a harbinger of bad luck.

The O-12 spent most of her career assigned to Submarine Division 1, based out of Coco Solo in the Panama Canal Zone. Her short naval career came to an end on June 17, 1924, when she was decommissioned and placed in reserve at the Philadelphia Navy Yard. Scheduled to be scrapped in accordance with the London Naval Treaty, the Secretary of the Navy turned her over to the U.S. Shipping Board who in turn chartered her to Lake & Danenhower, Inc., of Bridgeport, Connecticut, to be reconditioned for special arctic service. Since Wilkins was not an American citizen, the submarine could not be leased directly to him. The charter specified that a fee of $1 per year for five years was to be paid for her use, that the submarine would only be used for scientific research, and that she would be scrapped at the completion of the expedition.

Crew members inside control room

Initial modifications were begun at the Philadelphia Navy Yard, but when that facility was unable to perform the required work the submarine was moved across the river to the Mathis Shipyard in Camden, New Jersey. Thirty-two new features were added to the boat, designed by the original builder, Simon Lake. These included a cushioned guide arm, a cushioning bowsprit 12 feet long to act as a bumper, an ice drill to provide access to the surface in case the submarine was unable to break through the ice, an emergency air intake system, and a diving chamber. The original superstructure was removed, and the conning tower and periscope were modified to be retractable. Lake also had the deck fittings enclosed within a wooden superstructure four feet wide and six feet high, inside of which he installed extra buoyancy chambers, which he considered necessary to prevent loss of stability during surfacing. On top of the superstructure Lake installed iron-shod "sledge runners" and two cleats at each end. Wilkins did not concur with all of the modifications introduced by Lake, fearing that they were more likely dangers than aids. A verbal agreement between the two men, however, gave Lake the final say.

Nautilus leaving berth at Mathis Shipyard, Camden, NJ

Rechristened the Nautilus after Jules Verne's fictional vessel, the boat's record during the expedition was less then stellar. Plagued by mechanical difficulties and engine problems from the start, the crew were less than confident in their vessel's capabilities. When Captain Danenhower noticed that the diving rudders were missing on August 22, he suspected sabotage by the crew, and as a result of the damage, many of the scientific experiments had to be cancelled. After spending some additional time in the arctic, Wilkins headed back to port in Bergen, Norway, having failed in his mission.

Since it was deemed suicidal to sail the Nautilus back to the United States, the submarine was turned over to the Bergen Shipping Company, and with the approval of the U.S. Shipping Board, she was scuttled in international waters off Norway on September 29. Even this ignominious fate did not come easy: the first attempt to sink the Nautilus had to be called off due to bad weather. She was finally sunk on November 20, 1931, in the fjord a short distance from Bergen. A number of ships accompanied the boat as she was towed to the site where a valve was opened in the forward tank. The Nautilus filled with water and sank at 12:00 noon. Fifty years later, a team of Norwegian divers from Sjøteknik A/S located the wreck of the submarine. She remains in very good condition, which has begun talk of raising her to display in the Bergen Maritime Museum.