US Army M113 mortar carriers depart Samarra, Iraq after conducting an assault during Operation Baton Rouge, 2004.
The M113 is a fully tracked armored personnel carrier currently manufacured by BAE Systems. The vehicle was first fielded by United States Army's mechanized infantry units in Vietnam in April 1962. The M113 was the most widely used armored vehicle of the US Army in the Vietnam War, earning the nickname 'Green Dragon' by some people, but largely known as an APC or ACAV (armored cavalry assault vehicle) by the allied forces, as it was used to break through heavy thickets in the midst of the jungle to attack and overrun enemy positions.
The M113 introduced new aluminum armor that made the vehicle much lighter than earlier vehicles; it was thick enough to protect the crew and passengers from small arms fire but light enough that the vehicle was air transportable and moderately amphibious. In the US Army, the M113 series have long been replaced as front-line combat vehicles by the M2 and M3 Bradley, but large numbers are still used in support roles such as armored ambulance, mortar carrier, engineer vehicle, command vehicle, etc. The Army's Heavy Brigade Combat Teams are currently equipped with aroud 6,000 M113 and 4,000 Bradleys.
The M113's versatility spawned a wide variety of adaptations that live on worldwide, and in US service. These variants together represent about half of the US Army's armored vehicles today. To date, it is estimated that over 80,000 M113s of all types have been produced and used by over 50 countries worldwide, making it one of the most widely used infantry vehicle in history. The US Army planned to retire the M113 family of vehicles by 2018, seeking replacement with the GCV Infantry Fighting Vehicle program, but now replacement of the M113 has fallen to the Armored Multi-Purpose Vehicle program.
Development[]
FMC M113 prototype proposal
The M113 was developed by Food Machinery Corp. (FMC), which had produced the earlier M59 and M75 armored personnel carriers. The M113 bore a strong resemblance to both of these earlier vehicles. The M75 was too heavy and expensive to be useful; its weight prevented amphibious capability, and being transported by air. The lightened M59 addressed both of these problems, but ended up with too little armor, and was unreliable as a result of efforts to reduce its cost.
The Army was looking for a vehicle that combined the best features of both designs, the "Airborne Armored Multi-Purpose Vehicle Family" of all-purpose, all-terrain armored fighting vehicles FMC has been working with Kaiser Aluminum and Chemical Co. in the late 1950s to develop a suitable aluminum armor. Use of this armor could produce a vehicle that provided the protection of the M75, and the light weight and mobility of the M59.
FMC T117 proposal
FMC responded with two proposals; two versions of the aluminum T113 - a thicker and a thinner armored one - along with the similar but mostly steel T117. The thicker-armored version of the T113, effectively the prototype of the M113, was chosen because it weighed less than the steel competitor, but offered the same protection. An improved T113 design, the T113E1, was adopted by the US Army in 1960 as the M113. A diesel prototype T113E2 was put into production in 1964 as the M113A1, and quickly supplanted the gasoline-engined M113. In 1994, FMC transferred the M113's production over to its newly formed defense subsidiary, United Defense. Then in 2005, United Defense was acquired by BAE Systems.
US Army soldiers dismount from an M113 armored personnel carrier during a training exercise in September 1985.
The M113 was developed to provide a survivable and reliable light tracked vehicle able to be air-lifted and air-dropped, by C-130 and C-141 transport planes. The original concept was that the vehicle would be used soley for transportation, bringing troops forward under armor and then having them dismount for combat; the M113 would then retreat to the rear. Entering service with the US Army in 1960, the M113 required only two crewmen, a driver and a commander and carried 11 passengers inside the vehicle. Its main armament was a single .50 caliber (12.7mm) M2 Browning machine gun operated by the commander.
On 30 March 1962, the first batch of 32 M113s arrived in Vietnam, and were sent to two Army of the Republic of Vietnam (ARVN) mechanized rifle companies, each equipped with 15 of the APC's (M113s). On 11 June 1962, the two mechanized units were fielded for the first time. During the Battle of Ap Bac in Jan 1963, at least 14 of the exposed .50 caliber gunners aboard the M113s were killed in action, necessitating modifications to improve crew survivability. Soon, makeshift shields formed from metal salvaged from the hull(s) of sunken ships were fitted to the carriers, which afforded better protection. But, finding that this material could be penetrated by small arms fire, subsequent shields were constructed from scrapped armored vehicles.
Interior of an M113 at the American Armored Foundation Museum in Danville.
The ARVN 80th Ordnance Unit in South Vietnam developed the shield idea further and commenced engineering general issue gun shields for the M113. These shields became the predecessor to the standardized Armored Cavalry Assault Vehicle (or ACAV) variant and were issued to all ARVN mechanized units during the early 1960s. The ARVNs had modified the M113s to function as "amphibious light tanks" and not as battle taxis as US designers had intended. Instead of an armored personnel carrier, the ARVN used the carried infantry as extra "dismountable soldiers" in "an over-sized tank crew". These "ACAV" sets were eventually adapted to US Army M113s with the arrival of the Army's conventional forces in 1965. The vehicles continued to operate in the role of a light tank and reconnaissance vehicle, and did not operate as designed in the theater. Still, the M113 could carry 11 infantrymen inside, with two crewmen operating the M113.
The US Army, after berating the Vietnamese for flouting battle doctrine, came out with their own ACAV verison. This more or less standardized ACAV kit included shields and a circular turret for the .50 caliber M2 machine gun in the Track Commander (TC) position, two M60 machine guns with shields for the left and right rear positions, and "belly armor" - steel armor bolted from the front bottom extending 1/2 to 2/3 of the way towards the bottom rear of the M113. The two rear machine gunners could fire their weapons while standing inside the rectangular open cargo hatch. This transformed the M113 into a fighting vehicle, but the vehicle still suffered from its lightly armored configuaration, having never been designed for such a role.
In order to improve the fighting ability of the mounted troops, a number of experiments were carried out in the 1960s under MICV-65 project, which aimed to develop a true "infantry fighting vehicle" rather than an "armored personnel carrier". Pacific Car and Foundry entered the steel-armored XM701, but this proved to be too slow and heavy to be air-mobile, even in the C-141. FMC entered the XM734, which was largely the ACAV M113, but whereas the M113 seated the troops facing inward on benches along the walls, the XM734 sat them facing outwards on a central bench. Four gun ports and vision blocks were added on each side to allow the seated troops to fire even while under cover. Although neither of the vehicles were deemed worthwhile to produce, FMC continued development of their own version.
Modifications[]
United States Air Force M113 at the Theater Internment Facility at Camp Bucca, Iraq, 10 Feb 2008.
Modified versions of the Vietnam War ACAV sets have bben deployed to Iraq to equip the standard M113s still in service. The circular .50 caliber gun shields have been modified, however the rear port and starboard gun stations have been deleted for service in that region. Some of these modified vehicleshave been utilized for convoy escort duties.
The M113 has relatively light armor, but it can be augmented with add-on steel plates for improved ballistic protection. Also, reactive armor and slat armor can be added for protection against RPGs. Windowed gunshields developed by an armorer in Iraq are reminiscent of ACAV vehicle modifications so effective in Southeast Asia. Band tracks are in use by Canadian and some other forces to enabel stealthy operation, less damage to paved roads, less vibration, and rolling resistance.
Most of the 13,000 M113s which are still in US Army service have been upgraded to the A3 variant.
The M113 has also been adopted to replace the aging fleet of visually modified M551s being used to simulate Russian-made combat vehicles at the US Army's National Training Center in Fort Irwin, Calif. These M113s, like the M551s they replaced, have also been modified to resemble enemy tanks and APCs, like the T-80 and BMP-2.
Design[]
Armament[]
Australian M113A1 with the Cadillac Gage T50 turret fitted with twin mounted M1919 Browning and M2 Browning QCB machine guns.
The basic M113 armored personnel carrier can itself be fitted with a number of weapon systems. The most common weapon fit is a single .50 caliber M2 Browning machine gun. However, the mount can also be fitted with a 40mm Mk 19 automatic grenade launcher. A number of anti-tank weapons could be fitted to the standard variant: the US Army developed kits that allowed the M47 Dragon and BGM-71 TOW anti-tank missile systems to be mounted. In the case of the M47 dragon, the system mated to the existing gun mount, without having to remove the machine gun. This allowed the commander to use the weapon, as well as the machine gun. A large array of turrets and fixed mounts are available to mount high explosive cannon from 20mm to 105mm to the M113 series making them function also as assault guns and fire support means; while in many cases still having room inside to carry dismounted infantry or cavalry scouts.
Armor[]
The 10.5-ton M113 is built of 5083 aircraft-quality aluminum alloy which gives it some of the same strength as steel as a slightly reduced weight, as the greater thickness allows structural stiffness.
Mobility[]
Its weight allows the use of a relatively small engine to power the vehicle, a 6V53 Detroit 2-stroke six-cylinder diesel, with an Allison tx100 1-3 speed automatic transmission, and alloes the vehicle to carry a large payload cross-country and to be transported by fixed- and rotary-wing aircraft. The M113 can swim without deploying flotation curtains, and is propelled in the water by its tracks.
Service history[]
Vietnam[]
A combined arms operation in Vietnam. M113s clear the way through heavy bush while infantry follows.
The Vietnam war was the first combat opportunity for "mechanized' infantry, a technically new type of infantry with its roots in the armored infantry of WWII, now using the M113 armored personnel carrier. In addition, Armored Cavalry squadrons in Vietnam consisted largely of M113s, after replacing the intended M114 in a variety of roles, and armor battalions contained M113s with their headquarters companies, such as the maintenance section, medical section, vehicle recovery section, mortar section, and the scout (reconaissance) section. US Army mechanized infantry units in vietnam were fully equippd with the M113 APC/ACAV, which consisted of one headquarters company and three line companies, normally with an authorized strength of approximately 900 men. Ten US mechanized cavalry battalions and one mechanized brigade were deployed to Vietnam from 1965 until their departure in 1972.
ACAVs of the 3rd Squadron 11th Armored Cavalry assume a herringbone formation during Operation Cedar Falls. This formation gave vehicles optimal all-round firepower in the event of an ambush in a restricted area.
M113s were instrumental in conducting Reconnaissance In Force (RIFs), Search and Destory missions, and large invastions (incursions) such as during the US invasion of Cambodia on 1 May 1970 and later Laos (Operation Lam Son 719) in 1971; all of which used the M113 as the primary workhorse for moving the ground armies. While operating with Cavalry and Armor units, the M113s often worked in conjunction with US M48 Patton and M551 Sheridan tanks. During the Vietnam War, US Army gun trucks (modified 2 1/2-ton and 5-ton cargo trucks), along with V-100 armored cars, conducted convoy escorts for military traffic.
The USAF used M113 and M113A1 ACAV vehicles in USAF Security Police Squadrons, which provided air base ground defense support in Vietnam. M113s were also supplied to the South Vietnamese Army of the Republic of Vietnam (ARVN). One notable ARVN unit equipped with the M113 APC, the 3rd Armored Cavalry Squadron, earned the Presidential Unit Citation. M113s were also supplied to the Cambodian Khmer National Armed Forces, equipped with a turret for the machine gun and a recoilless rifle mounted on the roof.
The Australian Army also used the M113 in Vietnam. After initial experience showed the crew commander was too vulnerable to fire, the Australians tried a number of different gun shields and turrets, eventually standardizing with the Cadillac-Gage T-50 turred fitted with two .30 cal Browning machine guns, or a single .30/single .50 combination. Other turrets were tried as well as various gun shields, the main design of which was similar to the gun shield used on the US M113 ACAV version.
In addition, the Australians operated an M113 variant fitted with a Saladin armored car turret, with a 76mm gun as fire support vehicle, or FSV, for infantry fire support
Recent history[]
March 2007, a group of US Army soldiers sit on the rear ramp of an M113, staging for a reconnaissance mission in Forward Operating Base Kalsu, Iraq.
Today's M113 fleet includes a mix of M113A2 and A3 variants and other derivatives equipped with the most recent RISE (Reliability Improvements for Selected Equipment) package. The standard RISE package includes an upgraded propulsion system, greatly improved driver controls, external fuel tanks, and a 200-amp alternator with four batteries.
The future M113A3 fleet with include a number of vehicles that will have high speed digital networks and data transfer systems.
Law enforcement[]
M113s have been adopted by some law enforcement agencies. Photos show an M113 marked "Midland County Sheriff" was used in the 2008 raid of the Fundamentalist Church of Jesus Christ of Latter Day Saints compound. The Osceola County Sheriff also uses one for their S.W.A.T Team.
Brazilian Marine Corps' M113s have been used in joint operations with Batalhao de Operacoes Policiais Especiais during the raid on Complexo do Alemao.
Replacement[]
It was the US Army's intention that the BCT Ground Combat Vehicle Program replace the M113 by 2018 with the GCV Infantry Fighting Vehicle meanwhile displacing the other vehicles into taks specific roles of the M113. Vehicles displaced into specific roles of the M113 are then to be replaced entirely by future variants of the GCV.
The M113 will now be replaced by the Armored Multi-Purpose Vehicle (AMPV) program. Vehicles competing in the program are the Turretless Bradley and the Tracked Stryker.
Basic variants[]
M113[]
APC by David E. Graves, Vietnam Combat Artists Program.
Original version, powered by a 209 hp Chrysler 75M V8 petrol engine.
M113A1[]
Starting in 1964, the gasoline engine was replaced with a 215 hp diesel engine, to take advantage of the better fuel economy and reduced fire hazard of the diesel engine. The suffix A1 was used on all variants to denote a diesel engine, i.e. an M106A1 was an M106 mortar carrier equipped with a diesel engine.
M113A2[]
In 1979 further upgrades were introduced, including cooling and suspension improvements and smoke grenade launchers on the glacis plate. The suffix A2 is used on all variants to denote upgrade to A2 standard.
M113A3[]
In 1987 further improvements for "enhanced (battlefield) survival" were introduced. This included a yoke for steering instead of laterals, a more powerful engine, external fuel tanks and internal spall liners for improved protection. The suffix A3 is used to denote upgrade to A3 standard.
M113 Armored Cavalry Assault Vehicle (ACAV) variant[]
M113 ACAV in Vietnam, 1966.
The "'Armored Cavalry Assault Vehicle" or "ACAV" was a concept and field modification pioneered by the South Vietnamese Army (ARVN) in 1963 during the Vietnam War. ARVN troops utilized the M113 armored personnel carrier as an infantry fighting vehicle, and more often than not, as a light tank by fighting mounted rather than a "battle taxi" as dictated by US Army doctrine.
After it was found that the commander and cargo hatch positions were extremely exposed and the commander and troops hence vulnerable to enemy fire, the South Vietnamses engineers thought out a simple and cheap remedy to this problem: Initially field expedient shields and mounts were made from sunken ships, but this was soft metal and could be penetrated by small arms fire. Finally armor plate, from scrapped vehicles was used; this worked well and by the end of 1964, all ARVN ACAVs were equipped with gun shields. For the US Army, ACAV sets were produced industrially in Okinawa for the .50 cal machine gun, and rear aft and starboard M60 machine gun positions. Finally, the ARVN's ACAV modifications were adopted by the US Army in Vietnam, and by 1965 the full ACAV set was mass-produced in the US. The kit included shields and circular turret armor for the commander's M2 .50 caliber machine gun, and two additional 7.62mm M60 machine guns, again with shields, fitted on either side of the top cargo hatch. This kit could be retrofitted to any M113. ACAV sets were sometimes fitted to the M106 mortar carrier, but the differet rear hatch found on this vehicle required the left M60 machine gun to be fitted to the extreme rear instead the side. Many kits were added in the field, but at least in the case of the 11th Armored Cavalry Regiment, the vehicles had their ACAV sets installed in the US prior to their deployment to Vietnam in 1966. Additional armor in the form of a mine protective kit under the hull was also frequently fitted.
Derivatives[]
M58 Wolf System[]
US soldiers fire the M120 Mortar system out of an M113 at Camp Taji, Iraq, 2009.
A smoke screen generator vehicle.
M106[]
A mortar carrier armed with an M30 mortar mounted on a turntable in the rear troop compartment. On this variant, the single hatch over the rear troop compartment was exchanged for a three-part circular hatch. The mortar could be fired from the vehicle, but could also fire dismounted. Today, the US Army mortar carrier is the M106A4, an M106 upgraded to A3 standard armed with an M121 mortar, a variant of the M120mm mortar.
M125[]
Another mortar carrier, basically an M106 armed with an M29 81mm mortar.
M132[]
Flamethrower variant equipped with a turret armed with a flamethrower and a .50 caliber machine gun. These vehicles are no longer in use with the US Army.
M163[]
Anti-aircraft variant equipped with a turret armed with a variant of the 20mm M61 Vulcan cannon.
M48 Chaparral[]
Anti-aircraft variant equipped with a launcher armed with four MIM-72A/M48 Chaparral missiles
M548[]
Unarmored cargo carrier equipped with a rear cargo bed.
M577[]
M577 undergoing maintenance
Command variant, the roof over the rear troop compartment is higher. The vehicle also carries additional radios and a generator. A variant of this is the M1068 Standard Integrated Command Post System Carrier, equipped with the newest US Army automated command and control system.
M579[]
A fitter and repair vehicle equipped with a crane. This vehicle was not taken into US Army service.
M806[]
Repair and recovery vehicle equipped with an internal winch and two earth anchors mounted on the rear hull.
M901 ITV (Improved TOW Vehicle)[]
Equipped with a launcher armed with two TOW missiles.
M113 "MBT"[]
A variant of the M113 fitted with a modified Bradley turret as part of a VISmod package specifically for training. This version also featured MILES gear.
Others[]
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Lithuanian Army M113 fitter and repair vehicle.
A huge number of M113 variants have been created, ranging from infantry carriers to nuclear missile carriers. The M113 has become one of the most prolific armored vehicles of the second half of the 20th century, and continues to serve with armies around the world into the 21st century. Not without its faults, the otherwise versatile chassis of the M113 has been used to create almost every type of vehicle imaginable. Few vehicles ever created can claim the application to such a wide range of roles.
In 1994, a stretched version of the M113 was presented by its manufacturer, also known as "Mobile Tactical Vehicle Light" (MTVL). Its hull is lengthened by 34 inches and equipped with an additional road wheel (six on each side) to sustain the added dry weight and payload. The vehicle was developed as a "production-tooled demonstrator" with private-industry funding from United Defense. Although the US Army did not buy it, it was acquired by other nations and is copied today by Pakistan, Turkey and Egypt.
M113 Clones[]
Pakistan produces an armored personnel carrier known as Talha which has a number of mechanical and automotive parts in common with the M113. Turkey produces the ACV-300 based on the AIFV.