Mark 44 torpedo

It has been deployed by many navies and air forces including the USN, Royal Navy, Royal Australian Navy and the Royal Air Force from various launch vehicles. These include long-range maritime patrol aircraft, e.g. P-3 Orion, RAF Nimrod, Canadair Argus, LAMPS and other embarked naval helicopters, ASROC missiles, Ikara missiles.

• Name — Mark 44 torpedo • Origin — United States • Type — Antisubmarine torpedo • Is Ranged — yes • Is Explosive — yes • Is Missile — yes • Service — 1957-1967 (with United States Navy) • Used By — See Operators • Designer — Naval Ordnance Test Station Pasadena General Electric • Design Date — 1953 • Manufacturer — General Electric Naval Ordnance Station Forest Park American Machine and Foundry • Variants — Mark 44 Mod 1 • Weight — 432 lb • Length — 8.2 ft • Diameter — 12.75 in • Velocity — 123 m/s • Range — 123 m • Filling — Mk 101 Mod 0, HBX-3 • Filling Weight — 75 lb • Detonation — Mk 19 type Mod 12 contact exploder • Engine — Electric • Engine Power — 30 hp • Vehicle Range — 3.4 mi • Speed — 30 kn • Guidance — Helix search • Depth — 1000 ft • Launch Platform — Destroyers and aircraft

• Illustration — AD-4 Skyraider launching Mark 44 torpedo During the 1950s the US Navy ordered development of a new generation of lightweight anti-submarine torpedoes. Two programs were started, the EX-2A at the Naval Ordnance Test Station Pasadena (NOTS-Pasadena) and the EX-2B at General Electric Ordnance Department, Pittsfield, Massachusetts. The EX-2A was to have its counter-rotating propeller driven directly by an electric motor, while the EX-2B was to use a gas turbine connected to a gearbox. After an accident with the proposed fuel for the EX-2B (Propyl Nitrate) the US Navy ordered the halting of its use. This resulted in the EX-2B development team shifting to an electric motor using the design for a jet engine starter motor as the basis to give the high torque and RPM the counter-rotating gearbox needed. The shroud design around the control surfaces of the EX-2B was also redesigned, as it was discovered that having the shroud around the control surfaces themselves reduced their effectiveness, as a result the length of the shroud was reduced. After several evaluations the EX-2B was selected and designated the Mark 44 Mod 0. After some fine tuning of the design, an enhanced version the Mark 44 Mod 1 entered United States service in 1956. However shortly after the torpedo entered service it became apparent that newer Soviet submarines were both faster and deeper diving, and could potentially both outrun and out-dive the Mk.44 which was designed to attack targets with a maximum speed of only 17 knots. To address this an operational requirement was issued in 1960 resulting in the acceptance into service of the Mk.46 torpedo in 1963, when it began to replace the Mk.44 in U.S. service. A number of upgrade packages have been offered for the torpedo, a 1986 Honeywell kit replaced the magnetostrictive transducers with ceramic transducers in a planar array, and the replacement of the analogue guidance electronics with a digital system. The overall effect of these changes was to triple the searched volume of the torpedo by increasing detection range by 75% and reducing the minimum shallow water search depth by 47%. With this modification the torpedo is known in South Korea as the KT44. A South African package offered an extensive upgrade, replacing the warhead with a 45 kilogram shaped charge device capable of penetrating 40 millimeters of steel behind a 1.5 meter water filled double hull. The package also included a comprehensive digital electronics upgrade tripling the target acquisition range to 1,000 meters in ideal conditions, and containing a number of counter-counter measures along with a variety of attack modes. The torpedo is, however, coming to the end of its usable life as the batteries have expired in many of the torpedoes. The New Zealand navy retired its Mark 44s in 1993 because it decided against renewing the batteries.

• Mark 44 mod 0 - initial pre-production variant • Mark 44 mod 1 - initial production version • Mark 44 mod 2 • Mark 44 mod 3 • Mark 44 mod 4

• Illustration — Map with former Mark 44 operators in red

• Argentina • Australia • Brazil • Canada • Chile • Colombia • France • West Germany • Greece • Indonesia • Iran • Italy • Japan • Netherlands • New Zealand • Norway • Pakistan • Peru • Philippines • Portugal • South Korea • South Africa • Spain • Thailand • United States

• Length: 8.2 feet • Diameter: 12.75 inches • Weight: 432 lbs • Range: 3.4 miles • Speed: 30 knots • Depth range: 50 to 1,000 yards • Target detection range: 1,000 yards • Warhead: 75 lbs high explosive • Propulsion: 30 hp electric motor driven by seawater battery