Type
Air/surface/missile-launched, electrically
powered, homing torpedo.
Development
During the Second World
War the US Navy developed a number of 483 mm
(18 in) diameter lightweight torpedoes,
including the airborne Mk 24 or `Fido'
(which is claimed to have sunk 68
submarines) and the Mk 34 (which remained in
service until 1958). In the 1950s the
US Navy examined the possibility of much
smaller torpedoes, and in 1956 the Mk 44
lightweight torpedo entered service. The Mk
44 went on to become a standard item in the
NATO inventory. Launched from triple Mk 32
ship launchers, it was used as the original
payload of the ASROC and IKARA
anti-submarine missiles, and carried by a
wide range of helicopters and fixed-wing
aircraft. It was also produced under licence
in several other countries.
The Mk 44 had
not long been in service, when it became
apparent that the threat posed to US battle
groups by a new generation of deeper-diving,
faster and quieter former Soviet Union
submarines made it imperative that a more
capable torpedo be developed without delay.
An Operational Requirement was issued
in 1960 for a Mk 44 replacement, and studies
already in progress rapidly turned into
development of the Mk 46 torpedo (details of
which can be found in a separate entry).
The Mk 46
entered service in 1963 and immediately
began to replace the Mk 44 in the US
inventory. Although now obsolete in
the USA, as late as 1986 Honeywell (now
Raytheon Defense Systems) offered an upgrade
package for the Mk 44 torpedo.
In 1993 it
was reported that South Africa's Institute
for Maritime Technology (IMT) were
developing two upgrade packages for the Mk
44. The broad aim of the programme
was to develop an effective upgrade for
roughly 30 per cent of the cost of a new
torpedo. The first South African upgrade
produced a direct `fit, form, function' Mk
44 electronics replacement kit for the old
vacuum tube electronics. What started as the
second upgrade finished up as virtually a
new torpedo that is now called the Advanced
Mk 44 (A44) lightweight torpedo.
(For further details of
the A44 torpedo see separate entry)
The original air-launched
version of the Mk 44 was cleared for
carriage on a wide range of fixed- and
rotary-wing aircraft. It is
reportedly still carried by: Australian
S-70B Seahawk; Chilean Bell 206B JetRanger
III; and Iranian Agusta Bell AB 204
helicopters.
Description
The Mk 44 is a
lightweight torpedo of modular design
intended mainly for use against submarines.
It can be launched from helicopters
and fixed-wing aircraft as well as from
surface ships using Mk 32 torpedo tubes. The
torpedo consists of the following four major
sections: the whale-nosed front section that
houses the active sonar seeker with the
warhead behind it; guidance and gyro section;
battery section; and the propulsion section
with its four rectangular control fins,
electric motor and two contrarotating
propellers which, in the air-launched
version, are protected by a ring. The
air-launched version is fitted with a
parachute retarding system and usually a
nose protecting fairing, which would be
discarded as the torpedo entered the water.
The Mk 44 is 2.56 m long,
has a body diameter of 324 mm and weighs 233
kg. The warhead contains 34 kg of
high explosive and is probably activated by
a proximity fuze as well as an impact fuze.
Little information was ever released on the
guidance system except that an active
acoustic homing seeker is used, and depth
and course settings are passed to the
torpedo prior to launch. The Mk 44 is
reported to have a maximum range of around 5
km, a maximum speed of 30 kt and a maximum
operating depth of 300 m.
The Alliant
Techsystems (now Raytheon Defense Systems)
upgrade kit on offer includes a new nose
section, containing ceramic transducers in a
planar array rather than using the original
magnetostrictive type in an acoustic window.
The array includes a preamplifier,
and the analogue transmitter and receiver
are replaced by digital assemblies. The
upgrade is stated to increase the mean time
between failure from 160 to 3,000 hours,
while detection range is also increased by
75 per cent, volume searchrate is tripled
and the minimum shallow water search depth
is reduced by 47 per cent. Other
improvements include a new range gate to
reduce false alarms, and a new search mode
for intermediate depths.
Operational
status
Mk 44 entered service
with the US Navy in 1956 for use by fixed-
and rotary-wing aircraft, surface ships and
in ASROC. It proved so successful
that some 10,500 were produced for the US
Navy alone. It was exported to many
countries and eventually manufactured under
licence in Canada, France, Italy, Japan and
the UK. In Germany it was designated DM4,
while South Korea with a similar seeker
designated it KT44, and a South African
upgraded version is designated A44.
Though
replaced in the USA and some other navies by
its successor the Mk 46, it was reported in
1996 that the following navies were still
equipped with some Mk 44 torpedoes: Chile,
Indonesia, Iran, Philippines and Thailand.
Some of these countries may have
taken advantage of the Alliant Techsystems (now
Raytheon) or South African upgrade packages.
Chile and Iran may still be capable of
operating the Mk 44 torpedo in the
air-launched mode.
Specifications
Basic
Mk 44
Length: 2.56 m
Body diameter: 324 mm
Launch weight: 233 kg
Warhead: 34 kg HE
Guidance: Active sonar homing
Propulsion: Electric
Range: 5 km
Speed: 30 kt
Contractors
The Mk 44
is no longer manufactured, but upgrade kits
are produced by Raytheon Defense Systems,
Mukilteo, Washington, and Institute of
Maritime Technology, Simonstown, South
Africa.
