United States N-class submarine

For other uses, see N class.

The United States N-class submarines were a class of seven coastal defense submarines built for the United States Navy during World War I.

USS N-7 (SS-59)
Class overview
Name	N class
Builders	Seattle Construction and Drydock Co., Seattle, Washington (N-1 to N-3) Lake Torpedo Boat Co., Bridgeport, Connecticut (N-4 to N-7)
Operators	United States Navy
Preceded by	AA-1 class
Succeeded by	O class
Built	1915–1917
In commission	1917–1926
Completed	7
Scrapped	7
General characteristics
Type	Submarine
Displacement	N-1 to N-3: 347 long tons (353 t) surfaced 414 long tons (421 t) submerged N-4 to N-7: 331 long tons (336 t) surfaced 385 long tons (391 t) submerged
Length	N-1 to N-3: 147 ft 3 in (44.88 m) N-4 to N-7: 155 ft (47 m)
Beam	N-1 to N-3: 15 ft 9 in (4.80 m) N-4 to N-7: 14 ft 6 in (4.42 m)
Draft	N-1 to N-3: 12 ft 6 in (3.81 m) N-4 to N-7: 12 ft 4 in (3.76 m)
Propulsion	Diesel-electric N-1 to N-3: 2 × NELSECO 240V8FS Diesel engines, 600 hp (450 kW) total, 2 × Electro Dynamic electric motors, 300 hp (220 kW) total, 2 × 60-cell batteries, 2 × shafts N-4 to N-7: 2 × Busch-Sulzer Diesel engines, 600 hp (450 kW) total, 2 × Diehl electric motors,300 hp (220 kW) total, 2 × 60-cell batteries, 2 × shafts
Speed	13 knots (24 km/h; 15 mph) surfaced 11 knots (20 km/h; 13 mph) submerged
Test depth	200 ft (61 m)
Complement	N-1 to N-3: 25 officers and men N-4 to N-7: 29 officers and men
Armament	4 × 18-inch (450 mm) torpedo tubes, 8 torpedoes[1]

Description

The N-class boats were authorized under naval appropriations for Fiscal Year 1915. In order to be able to afford a fleet submarine in the same appropriations (eventually to become the AA-1 or T-class submarines), the Navy reduced the amount of money allocated to coastal submarines significantly. This forced them to order a more austere and smaller design. The N-class would be over 100 tons smaller than the preceding L-class boats, and would be the smallest boats built for the USN until 1952.^[2]

The boats were constructed by two companies to different specifications; N-1, N-2, and N-3 were designed by the Electric Boat Company of Groton, Connecticut and sub-contracted for construction to the Todd Dry Dock & Construction Company of Seattle, Washington, and N-4, N-5, N-6, and N-7 were designed and built by the Lake Torpedo Boat Company of Bridgeport, Connecticut. The N-boats built by Lake differ considerably from their EB brethren, but are of a similar size and have the same military characteristics and therefore are considered the same class.^[3]

The Electric Boat submarines had a length of 147 feet 3 inches (44.9 m) overall, a beam of 15 feet 9 inches (4.8 m) and a mean draft of 12 feet 6 inches (3.8 m). They displaced 347 long tons (353 t) on the surface and 414 long tons (421 t) submerged. The N-class submarines had a crew of 2 officers and 23 enlisted men. They had a diving depth of 200 feet (61.0 m).^[4]

The Lake submarines had a length of 155 feet (47.2 m) overall, a beam of 14 feet 6 inches (4.4 m) and a mean draft of 12 feet 4 inches (3.8 m). They displaced 331 long tons (336 t) on the surface and 385 long tons (391 t) submerged. The N-class submarines had a crew of 3 officers and 26 enlisted men. They also had a diving depth of 200 feet (61.0 m).^[4]

For surface running, the Electric Boat submarines were powered by two 240-brake-horsepower (179 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 280-horsepower (209 kW) electric motor. The Lake boats had 300-brake-horsepower (224 kW) diesels and 150-horsepower (112 kW) motors. Regardless of designer, the N-class submarines could reach 13 knots (24 km/h; 15 mph) on the surface and 11 knots (20 km/h; 13 mph) underwater.^[4] On the surface, the boats had a range of 3,500 nautical miles (6,500 km; 4,000 mi) at 11 knots (20 km/h; 13 mph) and 30 nmi (56 km; 35 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged.^[5]

The boats were armed with four 18-inch (450 mm) torpedo tubes in the bow. They carried four reloads, for a total of eight torpedoes. They were the last submarines to be designed without a deck gun until 1946.^[5] These boats retained the individual muzzle (outer) torpedo tube doors of the preceding L and M-classes.^[6]

This class was the first US Navy submarine class completed with metal bridge shields. These had been omitted from previous classes to increase underwater speed. The previous classes used piping-and-canvas temporary bridges for extended surface runs; these were found to be inadequate on North Atlantic patrols in World War I. All forward-deployed submarines were back-fitted with metal "chariot" bridge shields during the war. The coastal patrol nature of the small N-class submarines was emphasized by their lack of a deck gun.

Boats in class

The seven submarines of the N-class were:

Ship name and Hull no.	Builder	Laid Down	Launched	Commissioned	Decommissioned	Fate
N-1 (SS-53)	Seattle Construction and Drydock Company	26 July 1915	30 December 1916	26 September 1917	30 April 1926	Scrapped 1931
N-2 (SS-54)		29 July 1915	16 January 1917	26 September 1917	30 April 1926	Scrapped 1931
N-3 (SS-55)		31 July 1915	21 February 1917	26 September 1917	30 April 1926	Scrapped 1931
N-4 (SS-56)	Lake Torpedo Boat Company	24 March 1915	27 November 1916	15 June 1918	22 April 1922	Scrapped 1922
N-5 (SS-57)		10 April 1915	22 March 1917	13 June 1918	19 April 1922	Scrapped 1922
N-6 (SS-58)		15 April 1915	21 April 1917	9 July 1918	16 February 1922	Scrapped 1922
N-7 (SS-59)		20 April 1915	19 May 1917	15 June 1918	7 February 1922	Scrapped 1922

Service

Commissioned after the American entry into World War I, they were assigned to the 1st Naval District, primarily operating from Naval Submarine Base New London with some boats operating out of New York City at times, all patrolling the New England coast.

Built during a time in which USN submarine strategy and tactics were rapidly changing, the N-class coastal patrol submarines proved to be too small to be really useful to a Navy that was finding itself on the world stage. The Lake boats in particular were disliked for poor habitability and reliability. They served only an average of 3.5 years while the EB design boats averaged 8.5 years of service.^[7]

By 1922 the Seattle boats were assigned to the Submarine School, New London, while the Lake boats were all scrapped in that year, their engines having been removed in 1921 to re-equip some of the L class. The Seattle boats were decommissioned in 1926 and scrapped in 1931 to comply with the limits of the London Naval Treaty.