Bliss–Leavitt Mark 8 torpedo

Bliss–Leavitt Mark 8 torpedo
Bliss–Leavitt Mark 8 torpedo sitting on the deck of PT 21
Type	Anti-surface ship torpedo
Place of origin	United States
Service history
In service	1911–1945
Used by	United States Navy  Royal Navy
Wars	World War II
Production history
Designer	Frank McDowell Leavitt
Designed	1911
Manufacturer	Naval Torpedo Station Naval Gun Factory
Variants	Mod 1 Mod 2 Mod 2A Mod 2B Mod 3 Mod 3A Mod 3B Mod 3C Mod 3D Mod 5 Mod 6 Mod 8
Specifications
Weight	2,600 pounds
Length	256.3 inches (6.51 m)
Diameter	21 inches
Effective firing range	16,000 yards
Warhead	TNT, Mk 8 Mod 4
Warhead weight	466 pounds
Detonation mechanism	Mk 3 Mod 2, contact
Engine	Turbine
Propellant	Air (2800 psi, 23.4 cuft) Water (90 US pints or 43 l) Alcohol (49 US pints or 23 l)
Speed	36 knots (65.1 km/h)
Guidance system	gyroscope
Launch platform	Destroyers and PT boats

The Bliss–Leavitt Mark 8 torpedo was the United States Navy's first 21-inch by 21-foot torpedo. Although introduced prior to World War I, most of its combat use was by PT boats in World War II. The torpedo was originally designed in 1911 by Frank McDowell Leavitt of the E. W. Bliss Company and entered full mass production in 1913 at the Naval Torpedo Station in Newport, Rhode Island. It was deployed on destroyers and battleships during World War I and cruisers built in the 1920s. All US battleships and most cruisers had their torpedo tubes removed by 1941. The Mark 8 remained in service through World War II on older destroyers, primarily the Wickes and Clemson classes. It also equipped PT boats early in World War II, but was replaced by the Mark 13 torpedo on most of these in mid-1943.

Under the Lend-Lease Act, about 600 Mark 8 torpedoes were issued to the United Kingdom for use with 50 pre-1930 destroyers it received under the Destroyers for Bases Agreement.

The design was originally intended to be used on destroyers in an anti-surface ship role. When it was first released, it was a highly advanced torpedo, but when it was actually deployed into service during World War II it was showing its age and unable to compete with modern torpedo technology. The low speed of the torpedo was one of the complaints; its Japanese counterpart, the Type 93 torpedo, was significantly faster and more difficult to spot in the water.