|Name AA-1 class|
Preceded by USS M-1
|Operators United States Navy|
Succeeded by N class
|Builders Electric Boat Company (design) Fore River Shipbuilding|
The AA-1 class was a class of three experimental submarines of the United States Navy, built toward the end of World War I, between 1916 and 1919, intended to produce a high-speed fleet submarine. The design was not a success and none of the submarines saw active service. However, the lessons learned were applied to the design of the later V-boats. The class was later renamed as the T class.
In the early 1910s, only a dozen years after Holland inaugurated the Navy's undersea force, naval strategists had already begun to wish for submarines that could operate as long range reconnaissance vessels, in closer collaboration with the surface fleet than the Navy's existing classes, which had been designed primarily for coastal defense. These notional "fleet" submarines would necessarily be larger and better armed, but primarily, they would need a surface speed of some 21 knots (39 km/h; 24 mph) to be able to maneuver with the 21-knot battleships the battle fleet was built around. This was the designed speed of the Delaware class and later battleships, including the Standard-type battleships that were under construction and proposed in 1913.
In the summer of 1913, Electric Boat's chief naval architect, former naval constructor Lawrence Y. Spear, proposed two preliminary fleet-boat designs for consideration in the Navy's 1914 program. In the ensuing authorization of eight submarines, Congress specified that one should "be of a seagoing type to have a surface speed of not less than twenty knots." This first fleet boat, laid down in June 1916, was named Schley after Spanish–American War hero Winfield Scott Schley. With a displacement of 1,106 tons surfaced, 1,487 tons submerged, on a length of 270 feet (82 m), Schley (later AA-1, and finally T-1) was twice as large as any previous U.S. submarine. One drawback of the large size was that the design depth was reduced from 200 ft (61 m) to 150 ft (46 m). To achieve the required surface speed, two tandem 1,000 horsepower (750 kW) diesel engines on each shaft drove twin screws, and a separate diesel generator was provided for charging batteries. Although Schley and two sister boats authorized in 1915—AA-2 (later T-2), and AA-3 (later T-3)—all made their design speed of 20 knots (37 km/h; 23 mph), insoluble torsional vibration problems with their tandem engines made them very troublesome ships. As the engines were clutched together, it was impossible to perfectly synchronize their operation.
The engineering plant included four New London Ship and Engine Company (NELSECO) four-cycle six-cylinder diesels, 1,000 hp (750 kW) each in two tandem pairs, and two Electro Dynamic main electric motors, 675 hp (503 kW) each, directly driven by the engines. Two 60-cell Exide batteries provided submerged power. One NELSECO four-cycle four-cylinder auxiliary diesel generator was included to charge batteries while the main engines were operating at high speed. From 1923 to 1927, T-3 was re-engined with two German-built Maschinenfabrik Augsburg Nürnberg AG (MAN) four-cycle ten-cylinder diesels, 2,350 hp (1,750 kW) each.
In addition to the usual four bow 18-inch (457 mm) torpedo tubes, two single trainable external torpedo tubes were provided in the superstructure, immediately forward and aft of the sail. These could fire on either broadside, but not dead ahead or dead astern. Two 3-inch (76 mm)/23 caliber retractable deck guns were also equipped. As with other contemporary US submarine designs, the AA-1 class was optimized for a high submerged speed, with a small sail and retractable deck guns. In August 1918 T-1 was experimentally rearmed with a single 4-inch (102 mm)/50 caliber non-retractable gun at the expense of the forward trainable torpedo tube, probably to test the effect of a bigger gun on submerged speed as well as provide more anti-ship firepower. Larger submarine deck guns were considered because many German U-boats were equipped with guns of up to 105 mm (4.1 in) and some were equipped with 150 mm (5.9 inch) guns. The 4 inch gun would later become standard on the S-class submarines.
They were based out of Hampton Roads, Virginia as part of Submarine Division 15 in the Atlantic Fleet and were used for training and maneuvers. On 23 August 1917, Schley was renamed AA-1 prior to launching, to free the name for the destroyer Schley. On 17 July 1920, the three boats were reclassified as Fleet Submarines and given the hull numbers SF-1, SF-2, and SF-3. Their names were changed from the AA-series to T-1, T-2, and T-3 on 22 September 1920.
All three boats had been decommissioned by 1923 and placed into storage at Philadelphia, Pennsylvania. Between 1925 and 1927, T-3 was restored to service in order to test German-built diesels (2,350 hp (1,750 kW) MAN engines), then returned to Philadelphia. All three were struck from the Naval Vessel Register on 19 September 1930 and sold for scrap on 20 November 1930.