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Alligator (submarine)

USS Alligator 0844401.jpg
Contemporary artist's rendering of Alligator
History
United States of America
Name: Alligator
Namesake: Alligator mississippiensis
Ordered: 1 November 1861
Builder: Neafie & Levy
Launched: 1 May 1862
In service: 13 June 1862
Fate: Foundered 2 April 1863
Status: Lost
General characteristics
Displacement: 275 tons surface, 350 tons submerged
Length: 47 ft (14 m)
Beam: 4 ft 6 in (1.37 m) (excluding oars); height of hull 6 ft (1.8 m)
Propulsion:
  • 1862: 16 × hand-powered oars
  • 1863: Hand-cranked propeller
Speed: 1862: 2 knots (3.7 km/h); 1863: 4 knots (7.4 km/h)
Test depth: 6.8 ft (2.1 m)
Complement: 12 - One officer, one helmsman, one or two divers, and 8 oarsmen
Armament: 2 × limpet mines

The USS Alligator, the fourth United States Navy ship of that name, is the first known U.S. Navy submarine, and was active during the American Civil War. The first American submarine, built during the Revolutionary War, was Turtle, which the civilian David Bushnell designed and built, and Sergeant Ezra Lee of the Continental Army operated.

In the autumn of 1861, the Navy asked the firm of Neafie & Levy to construct a small submersible ship designed by the French engineer Brutus de Villeroi, who also acted as a supervisor during the first phase of the construction.

The ship was about 30 ft (9 m) long and 6 ft (1.8 m) or 8 ft (2.4 m) in diameter. "It was made of iron, with the upper part pierced for small circular plates of glass, for light, and in it were several water tight compartments." She was designed to carry eighteen men. For propulsion, she was equipped with sixteen hand-powered paddles protruding from the sides, but on 3 July 1862, the Washington Navy Yard had the paddles replaced by a hand-cranked propeller, which improved its speed to about four knots. Air was to be supplied from the surface by two tubes with floats, connected to an air pump inside the submarine, and was the first operational submarine to have an air purifying system. The ship had a forward airlock, and was the first operational submarine with the capability for a diver to leave and return to the vessel while both remained submerged. Divers could affix mines to a target, then return and detonate them by connecting the mine's insulated copper wire to a battery inside the vessel.

The Navy wanted such a vessel to counter the threat posed to its wooden-hulled blockaders by the former screw frigate Merrimack which, according to intelligence reports, the Norfolk Navy Yard was rebuilding as an ironclad ram for the Confederacy (the CSS Virginia). The Navy's agreement with the Philadelphia shipbuilder specified that the submarine was to be finished in not more than 40 days; its keel was laid down almost immediately following the signing on 1 November 1861 of the contract for her construction. Nevertheless, the work proceeded so slowly that more than 180 days had elapsed when the novel craft finally was launched on 1 May 1862.


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