Mark 44 torpedo
Encyclopedia
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, and under licence in Canada, France, Italy, Japan and the United Kingdom with 10,500 being produced for U.S. service. It was superseded by the Mark 46 torpedo
Mark 46 torpedo
Designed to attack high-performance submarines, the Mark 46 torpedo is the backbone of the U.S. Navy's lightweight ASW torpedo inventory, and is the current NATO standard. These aerial torpedoes, such as the Mark 46 Mod 5, are expected to remain in service until the year 2015...
. The Royal Australian Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
, however, continued to use it alongside its successor for a number of years, because the Mark 44 was thought to have superior performance in certain shallow-water conditions.
Deployed by many navies and air forces including the USN, Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
, Royal Australian Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
and the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
from various launch vehicles. These include long-range maritime patrol aircraft
Maritime patrol
Maritime patrol is the task of monitoring areas of water. Generally conducted by military and law enforcement agencies, maritime patrol is usually aimed at identifying human activities....
, e.g. P-3 Orion
P-3 Orion
The Lockheed P-3 Orion is a four-engine turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner. The aircraft is easily recognizable by its distinctive tail stinger or...
, RAF Nimrod, LAMPS
Light airborne multi-purpose system
Light Airborne Multi-Purpose System is the United States Navy's program that developed manned helicopters that assist the surface fleet in anti-submarine warfare.*SH-2 Seasprite *SH-60 Seahawk...
and other embarked naval helicopters
Light airborne multi-purpose system
Light Airborne Multi-Purpose System is the United States Navy's program that developed manned helicopters that assist the surface fleet in anti-submarine warfare.*SH-2 Seasprite *SH-60 Seahawk...
, ASROC missiles
ASROC
ASROC is an all-weather, all sea-conditions anti-submarine missile system. Developed by the United States Navy in the 1950s, it was deployed in the 1960s, updated in the 1990s, and eventually installed on over 200 USN surface ships, specifically cruisers, destroyers, and frigates...
, Ikara missiles
Ikara (missile)
The Ikara missile was an Australian ship-launched anti-submarine missile, named after an Australian Aboriginal word for "throwing stick". It launched an acoustic torpedo to a range of , allowing fast-reaction attacks against submarines at ranges that would otherwise require the launching ship to...
.
Development
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, Pitsfield. 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 the having 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
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
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 magentostrictive 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%. The so-upgraded Torpedo is in South Korea
South Korea
The Republic of Korea , , is a sovereign state in East Asia, located on the southern portion of the Korean Peninsula. It is neighbored by the People's Republic of China to the west, Japan to the east, North Korea to the north, and the East China Sea and Republic of China to the south...
as the KT44.
A South African upgrade 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.
Description
The Mark 44 is a modular design, consisting of four main sections. The blunt nose contains the active sonar seeker with the 75 pound (34 kg) high explosive warhead immediately behind it. The second section contains the guidance and gyroscopes. The third contains the 24 kilowatt seawater battery which uses silver chloride and magnesium electrodes with seawater acting as the electrolyte. Finally is the propulsion section which houses the electric motor, four rectangular control fins and two contra-rotating propellers.The vacuum tube based guidance system is more sophisticated than earlier torpedoes, using pre-launch settings enabling an initial search depth of 50,150,250,450,650 or 900 feet as well as a search floor at 150,250,450,650 or 900 feet as well as a maximum dive/climb angle of 4.5,6 or 7 degrees. On impacting the water the torpedo either runs out for 1,000 yards or performs a dive at a 30 degree angle to the search depth. After completing this it may perform a flat turn and begins a helical search pattern proceeding up or down until it hits either the minimum depth of 50 yards or the search floor. When it hits either top or bottom it performs a flat turn and begins to execute the search in reverse. It continues executing this search until it either finds a target or exhausts its six minute endurance.
The guidance system could drive the active sonar at either a slow rate or a fast rate, which it used when the target drew near to obtain a precise proximity and rate of closure.
The air dropped version of the torpedo is fitted with a parachute retarding system to slow entry into the water, and the nose is protected from the impact by a fairing which is immediately discarded upon entering the water. The propellers are covered by a ring fairing.
Specifications
- 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
Variants
- 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
Users
This is a list of past and present users of the Mark 44. In many cases the torpedo is only kept in reserve.Australia, Brazil, Canada, Chile, Colombia, Germany, Greece, Indonesia, Iran, Italy, Japan, South Korea, Netherlands, New Zealand, Norway, Pakistan, Peru, Philippines, Portugal, South Africa, Spain, Thailand, Tunisia, Turkey, United States, Uruguay, and Venezuela.