The OT-62 is a tracked amphibious vehicle that was jointly developed and used by Czechoslovakia and Poland. It is equivalent to the Soviet BTR-50PK APC and in appearance is almost identical to the BTR-50PU model 2 command vehicle with some significant differences. These differences include higher road and water speeds, a fully enclosed troop compartment and in some versions, fully-enclosed armament installations rather than simple pintle-mounted machine guns. TOPAS is the official designation of this armored personnel carrier with the designation "OT-62" often being used in the West. The Western term "OT-62" will be used principally in this lesson.

The OT-62A is the basic version of the OT-62 series APCs and has no fixed armament. Some variants include a command vehicle, armored ambulance and light armored recovery vehicle (TOPAS-WPT). Other OT-62 variants are discussed below.

OT-62B (TOPAS-2A). This version is used only by Czechoslovakia and has a mini-turret on the right front of the vehicle, which mounts a 82-mm recoilless gun externally and 7.62mm machine gun internally. Maximum rate of fire in rds/min for the 82-mm gun is one plus, depending upon the availability of an outside loader. Basic load for the 82-mm gun is 5 to 10 rounds.

OT-62C (TOPAS-2AP). This version has a turret similar to the Soviet BTR-60PB. Main armament is a 14.5-mm heavy machine gun mounted in the turret over the troop compartment. Secondary armament is a coaxially-mounted 7.62-mm machine gun. A practical rate of fire for the 14.5-mm gun is 150 rds/min with a basic load of 500 rounds. A practical rate of fire for the 7.62mm gun is 200 rds/min with a basic load of 1,000 to 2,000 rounds. This version and the modified OT-62C version below are used only by the Polish Armed Forces within the Warsaw Pact.

OT-62C Modified (TOPAS-2AP). This version carries two 82-mm mortars and their crews. The mortars have a rate of fire of 25 rds/min with a load of 50 to 100 rounds.

The OT-62 has

• six road wheels, no return rollers and a torsion bar suspension.

• a wedge-shaped front and a lowered rear.

• an enlarged bay on the right side of the crew compartment.

• entry/exit doors on both sides of the troop compartment.

• a commander's cupola with a periscope mounted in the forward part and a hatch cover that opens forward and can be locked vertically.

• three commander's periscopes mounted in the front part of the left projecting bay.

• a driver's single-piece hatch cover in front of the vehicle that opens upward and has an integral vision block.

• three periscopes below the driver's hatch cover.

• three observation periscopes in the right projecting bay.

The OT-62 is a fully amphibious vehicle that is propelled through the water by canted twin water jets in the rear. The hull is all-welded construction with the crew compartment at the front, troop compartment at the center and the engine at the rear. The commander is seated at the front of the vehicle in the left projecting bay with the driver seated to the right of the commander. Specifications for the OT62 are provided in the lists and paragraphs that follow.