PB-4

The PB-4 (Plavayushchiy Broneavtomobil, "floating armoured car") was developed in 1933 as a more reliable and better-armed successor to the BAD-2. It was built in a small series, about ten vehicles, in 1933-34. Like the BAD-2, it used a Ford-Timken 6x4 chassis. It carried the turret of the T-26 light tank with a 45 mm Model 1932 gun and two 7.62 mm DT machine guns.

For swimming it had a screw propeller, cork-filled pontoons along the sides and an outboard water heat exchanger for the engine. Removable tracks could be fitted, as on other Soviet 6x4 armoured cars. It weighed 5.28 tonnes, measured 5.3 x 1.98 x 2.25 m and had a crew of four, with armour of 4-7 mm. Its 40 hp engine gave 50 km/h on roads and 4 km/h in water, with a range of 140-200 km.

The PB-4 was fairly successful, but it lacked power and cross-country ability, especially in marshes. Because the Red Army had good amphibious light tanks such as the T-37A and T-38, few amphibious armoured cars were built. A preserved PB-4 is at the Kubinka tank museum.