United States S-class submarine

	S-class submarine USS S-44 (SS-155) leaving Guantanamo Bay, Cuba, c. 1929
Class overview
Name	S class
Builders	Fore River Shipyard (S-1 and S-42-class); Union Iron Works (S-1-class); Portsmouth Navy Yard (S-3-class); Lake Torpedo Boat (S-2, S-3 and S-48-class);
Operators	United States Navy; Polish Navy; Royal Navy;
Preceded by	R class
Succeeded by	V-boats
Subclasses	S-1, S-2, S-3, S-18, S-42, and S-48
Built	1918–1925
In commission	1920–1946
Planned	65
Completed	51
Canceled	14
Lost	9
Retired	42
General characteristics Prototype S-class boats
Type	Submarine
Displacement	800–875 long tons (813–889 t) surfaced; 977–1,088 long tons (993–1,105 t) submerged;
Length	207 ft 0 in – 231 ft 0 in (63.1–70.4 m)
Beam	19 ft 7 in – 21 ft 1 in (5.98–6.43 m)
Draft	13 ft 1 in – 16 ft 2 in (4–4.93 m)
Depth	200 ft (61 m)
Installed power	1,200–1,800 bhp (890–1,340 kW) diesel; 1,200 hp – 1,500 hp (1,100 kW) electric;
Propulsion	2 × NELSECO or Busch-Sulzer diesel engines; 2 × Electro-Dynamic Company, Diehl Manufacture Company, or Westinghouse Electric Corporation electric motors; 1 × 120-cell battery; 2 × Propellers;
Speed	14.5–15 kn (26.9–27.8 km/h; 16.7–17.3 mph) surface; 11 kn (20 km/h; 13 mph) submerged;
Complement	4 officers; 34 enlisted;
Armament	4 × 21 inch (533 mm) torpedo tubes (bow), 12 torpedoes; (S-10 to S-17 and S-48 to S-51 had an additional 21 inch stern tube with 2 additional torpedoes); 1 × 4-inch (102 mm)/50 caliber deck gun;

The United States' S-class submarines, often simply called S-boats (sometimes "Sugar" boats, after the contemporary Navy phonetic alphabet for "S"), were the first class of submarines with a significant number built to United States Navy designs. They made up the bulk of the USN submarine service in the interwar years and could be found in almost every theater of operations. While not considered fleet submarines, they were the first submarines in the USN designed for open ocean, blue water operations. All previous submarines had been intended for harbor or coastal defense. These boats were intended to have greater speed and range than previous classes, with improved habitability and greater armament.

The S-class were designed during World War I, but not completed until after the war. Many boats of the class remained in service through World War II.

The United States Navy commissioned 51 S-class submarines from 1920 to 1925. The first boat in name sequence, USS S-1 (SS-105), was commissioned in 1920, and the last numerically, USS S-51 (SS-162), in 1922. Severe production difficulties encountered by the Electric Boat Company (EB) threw the production sequence into disarray and the last of the class actually commissioned was USS S-47 (SS-158), in September 1925.

The boats built by EB are referred to as the S-1 class, S-18 class, or Holland type. The Lake built S-2 design, was rejected by the Navy and was not repeated. The Navy built boats are referred to as the S-3 or S-4 class, the "Navy" type, the "Bureau" type, or the "Government" type. The Navy did contract Lake to build boats of their design.