The ''Allende'' class is a series of anti-submarine frigates used by the

Mexican Navy The Mexican Navy is one of the two independent armed forces of Mexico. The actual naval forces are called the ''Armada de México''. The ''Secretaría de Marina'' (''SEMAR'') (English: Naval Secretariat) includes both the ''Armada'' itself and ...

. ''Allende''-class frigates are former

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

-ships which were acquired beginning in 1997. They form the Mexican Gulf Fleet of the Mexican Navy. They are used for anti-submarine and offshore patrol duties.

Description

The ''Allende''-class frigates are former

s. They have a

standard displacement The displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into wei ...

of and at full load. The vessels measure long with a

beam Beam may refer to: Streams of particles or energy * Light beam, or beam of light, a directional projection of light energy ** Laser beam * Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized g ...

of and a maximum draught of . The ships are propelled by a Westinghouse

steam turbine A steam turbine is a machine that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Charles Parsons in 1884. Fabrication of a modern steam turb ...

rated at turning one

shaft Shaft may refer to: Rotating machine elements * Shaft (mechanical engineering), a rotating machine element used to transmit power * Line shaft, a power transmission system * Drive shaft, a shaft for transferring torque * Axle, a shaft around wh ...

using steam provided by two Combustion Engineering/

Babcock & Wilcox Babcock & Wilcox is an American renewable, environmental and thermal energy technologies and service provider that is active and has operations in many international markets across the globe with its headquarters in Akron, Ohio, USA. Historicall ...

boilers at a working pressure of and a temperature of . This gives the frigates a maximum speed of and a range of at on one boiler. The ships have a complement of 288 including 20 officers. The frigates are armed with a reduced version of their American layouts. They mount a single FMC /54 caliber Mk 42

dual purpose gun A dual-purpose gun is a naval artillery weapon mount, mounting designed to engage both surface and air targets. Description Second World War-era capital ships had four classes of artillery: the heavy main battery, intended to engage opposing ba ...

mounted forward. For

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typi ...

(ASW), the frigates are equipped with an

ASROC The RUR-5 ASROC (for "Anti-Submarine Rocket") 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 ...

Mk 16 octuple launcher with a reload system sited between the

superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships. Aboard ships and large boats On water craft, the superstruct ...

and the 5-inch gun. Two cells were re-configured to fire

Harpoon A harpoon is a long spear-like instrument and tool used in fishing, whaling, sealing, and other marine hunting to catch and injure large fish or marine mammals such as seals and whales. It accomplishes this task by impaling the target animal ...

surface-to-surface missiles in American service, but this ability was not transferred to the Mexican Navy. The ''Allende'' class also mounts two twin Mk 32 torpedo launchers in fixed tubes for 22

Mk 46 torpedo The Mark 46 torpedo is the backbone of the United States Navy's lightweight anti-submarine warfare torpedo inventory and is the NATO standard. These aerial torpedoes are designed to attack high-performance submarines. In 1989, an improvement ...

es. The launchers are sited on the midships structure, angled outward at a 45° angle. ''Allende'' retains the Mk 25 launcher for the

Sea Sparrow RIM-7 Sea Sparrow is a U.S. ship-borne short-range anti-aircraft and anti-missile weapon system, primarily intended for defense against anti-ship missiles. The system was developed in the early 1960s from the AIM-7 Sparrow air-to-air missile as ...

surface-to-air missiles that the vessels mounted in American service. The class is equipped with fixed Mk 36 SRBOC 6-barreled decoy launchers for

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from aroun ...

and chaff,

SLQ-25 Nixie The AN/SLQ-25 Nixie and its variants are towed torpedo decoys used on US and allied warships. It consists of a towed decoy device (TB-14A) and a shipboard signal generator. The decoy emits signals to draw a torpedo away from its intended targe ...

towed torpedo decoys and SLQ-32CV2

electronic support measures In military telecommunications, electronic support (ES) or electronic support measures (ESM) gather intelligence through passive "listening" to electromagnetic radiations of military interest. They are an aspect of electronic warfare involving ac ...

. They mount a Mk 68 Mod gunfire control system for the 5-inch guns, a Mk 114 Mod 6 control system for the ASW armament, a Mk 1 target designation and a MMS target acquisition system. For

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

, the ''Allende'' class have

SPS-40 The AN/SPS-40 is a United States Navy two-dimensional, long range air search radar that is capable of providing contact bearing and range. It was used on s, s, s, s, s, s, s, s, s, s and many other ship classes. Its "basket" antenna with the ove ...

air search and SPS-10 or

SPS-67 The AN/SPS-67 is a short-range, two-dimensional, surface-search/navigation radar system that provides highly accurate surface and limited low-flyer detection and tracking capabilities. History The AN/SPS-67 is a solid-state replacement for the AN ...

surface search. The vessels are equipped with SPG-53D/F fire control radar and SRN-15A

TACAN A tactical air navigation system, commonly referred to by the acronym TACAN, is a navigation system used by military aircraft. It provides the user with bearing and distance (slant-range or hypotenuse) to a ground or ship-borne station. It is a mor ...

. The ''Allende'' class have a SQS-26CX bow-mounted

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects on ...

capable of active search and attack. The frigates have a

helipad A helipad is a landing area or platform for helicopters and powered lift aircraft. While helicopters and powered lift aircraft are able to operate on a variety of relatively flat surfaces, a fabricated helipad provides a clearly marked hard ...

located over the stern of the ship and a

hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...

capable of storing the

MBB Bo 105 The Messerschmitt-Bölkow-Blohm Bo 105 is a light, twin-engine, multi-purpose helicopter developed by Bölkow of Ottobrunn, West Germany. It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform ae ...

helicopter that operates off the vessels.

Ships in class

Service history

The first two ships were acquired by the

on 29 January 1997 and underwent refits for Mexican service. Both ships were commissioned on 23 November 1988. The third ship was acquired in 2000 and the fourth in 2001. ''Mina'' is based at Manzanillo, the other three at

Tampico Tampico is a city and port in the southeastern part of the state of Tamaulipas, Mexico. It is located on the north bank of the Pánuco River, about inland from the Gulf of Mexico, and directly north of the state of Veracruz. Tampico is the fifth ...

. ''Victoria'' commissioned on 16 March 2000 and ''Mina'' on 1 November 2002.

Citations

References

* * {{DEFAULTSORT:Allende-class frigate Frigates of the Mexican Navy Frigate classes