The M59 was an American armored personnel carrier that entered service in the spring of 1954 replacing the M75. It had three key advantages over the M75: it was amphibious, had a lower profile, and was considerably cheaper to produce. Production ended in 1960, by which time approximately 6,300 had been built. The M84 Mortar Carrier was a derivative of the M59. The M59 was replaced in service by the M113 family of vehicles.
Development
Development work on a replacement for the M75 began in late 1951, with the Food Machinery and Chemical Corporation producing a number of prototypes. The best performing of these, the T59, was selected and type classified as the M59 in May 1953. FMC was awarded the production contract.
In order to keep costs down, instead of a single large powerful engine, the vehicle used two smaller, less powerful civilian truck engines, mounted one each side of the hull. The unreliability of this power system, along with the reduced armor protection provided compared to the M75, were the major disadvantages of this APC.
Description
The vehicle has a welded steel hull ranging in thickness from 0.375 inches (0.95 cm) on the top to 1 inch (2.49 cm) thick on the belly with the median thickness being 0.625 inches (1.59 cm). Overall, it is rather slab sided in appearance with a blunt nose. The vehicle has a single large compartment with the driver sitting at the front left, and the commander sitting to his right. The driver is provided with an M19 infra-red night vision periscope and several M17 periscope for driving in a buttoned up position. The commander has an M13 cupola, with a .50-caliber M2 machine gun, for which 2,205 rounds are carried in the vehicle.
Behind the commander and driver are two benches, which run down the sides of the vehicle for the ten passengers. The benches can be folded up to make room for a single jeep. On either side of the passenger compartment are side sponsons, which contain the vehicle's drive train.
The drive train consists of twin GMC Model 302 6-cylinder inline petrol engines, each developing 146 hp at 3600 rpm. Both engines were directly connected to a Hydramatic model 301MG transmission (early models used 300MG) with four forward speeds and one reverse. Steering is through controlled differential via steering levers at the drivers station. The track is driven by a drive sprocket at the front. There are five road wheels per side, along with three return rollers. The vehicle uses torsion bar suspension and has shock absorbers on the first and last road wheel. The vehicle has a top road speed of about 32 miles per hour, considerably less than that of its M75 predecessor.
135 gallons (511 liters) of petrol could be carried, giving it a road range of approximately 120 miles (150 km).
The vehicle was designed to be amphibious, with rubber seals on all hatches and doors. A trim vane is provided. In the water, it has a maximum speed of 4.3 miles per hour (6.9 km/h).
The passengers are provided with a ramp at the rear of the vehicle, which has an escape door set into it. Hatches on the top of the vehicle are also provided.
M84 Mortar Carrier
The M84 was a modified M59 that carried a 4.2-inch M30 mortar pointing backwards attached to the floor in the bay. Roof plates on the M84 could be opened to allow the mortar to be fired from inside the vehicle. The M84 only carried a crew of six, but weighed 47,100 lbs (21,400 kg) because of the mortar and the combat load of 88 rounds. The M84 entered production in January 1957. It was replaced by the M106 mortar carrier.
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