Mark 14 Torpedo

Mark 14 torpedo
Mark 14 torpedo side view and interior mechanisms, as published in a service manual
Type	Anti-surface ship torpedo
Place of origin	United States
Service history
In service	1931–1980
Used by	United States Navy
Wars	World War II
Production history
Designer	Naval Torpedo Station Newport, Rhode Island
Designed	1931
Manufacturer	Naval Torpedo Station Newport, RI Naval Torpedo Station Alexandria, VA Naval Torpedo Station Keyport, Washington Naval Ordnance Plant Forest Park, IL
Produced	1942-1945
Number built	13,000
Specifications
Weight	3,280 lb (1,490 kg)
Length	20 ft 6 in (6.25 m)
Diameter	21 in (530 mm)
Effective firing range	4,500 yards (4,100 m) at 46 knots (85 km/h) 9,000 yards (8,200 m) at 31 knots (57 km/h)
Warhead	Torpex
Warhead weight	643 lb (292 kg)
Detonation mechanism	Contact or magnetic pistol
Engine	Wet-heater combustion / steam turbine with compressed air tank
Propellant	Methanol
Speed	46 knots (85 km/h)
Guidance system	Gyroscope
Launch platform	Submarines

The Mark 14 torpedo was the United States Navy's standard submarine-launched anti-ship torpedo of World War II. This weapon was plagued with many problems which crippled its performance early in the war. It was supplemented by the Mark 18 electric torpedo in the last two years of the war. Nonetheless, the Mark 14 played a major role in the devastating blow US Navy submarines dealt to the Japanese naval and merchant marine forces during the Pacific War.

By the end of World War II, the Mark 14 torpedo was a reliable weapon which remained in service for almost 40 years in the US Navy, and even longer with other navies.

The design of the Mark 14 started in January 1931; the Navy allocated $143,000 for its development (equivalent to $2,252,015 in 2016). The Mark 14 was to serve in the new "fleet" submarines and replace the Mark 10 which had been in service since World War I and was standard in the older R- and S-boats. Although the same diameter, the Mark 14 was longer, at 20 ft 6 in (6.25 m), and therefore incompatible with older submarines' 15 ft 3 in (4.65 m) torpedo tubes. (Later in the war, BuOrd stopped producing Mark 10s for the S-boats and provided a shortened Mark 14.)

Torpedoes consist of several subsystems, and those subsystems evolved over time. Torpedoes are also tailored for their application. Submarine torpedoes, such as the Mark 14, are constrained by the dimensions of the submarines torpedo tubes: 21 inches in diameter and a certain maximum length. Submarines are expected to close with their targets, so the torpedoes do not need a long range. In contrast, torpedoes fired by destroyers need greater range because their approach would be under fire from their targets. Improvements in the propulsion engine power output allowed the Mark 14 to have a top speed of 46 knots compared to the Mark 10 Mod 0's 30 knots. Steering is controlled by a gyroscope; the gyro on the Mark 10 Mod 0 was spun up in the torpedo tube and was not powered after launch; the gyro on the Mark 14 was continuously powered by its air flask. The depth control on the Mark 10 was slow — the depth would not stabilize quickly; the Mark 14 depth stabilization was improved.