The M59 was designed as a lower-cost alternative to the M75 armored infantry vehicle. The engines and transmissions of the M59 were in either sponson, leaving the cargo and personnel area free. Troop access to the vehicle was through a large rear ramp which was fitted with an escape hatch, and through roof hatches over the passenger compartment. M59s were amphibious, and a trim vane was located on the hull front slope. Early vehicles were fitted with the Model 300MG Hydramatic transmissions. Early M59s also featured a rotating mount for an M2HB .50cal machine gun around the commander's vision cupola. The commander's cupola on mid-production vehicles sported periscopes instead of the earlier vision blocks, but retained the external .50cal MG mount. Late-production M59s were fitted with the M13 cupola, which was armed with an internally-mounted .50cal machine gun. The early cupolas produced a height of 102.6" (260.6cm), and the mid-production cupolas were 112.5" (285.8cm) tall. Vehicles lacking the M13 cupola could only stow 1470 rounds of .50cal ammunition.