propellers, also known as BTR-1015B) and Ob'yekt 1020B (developed by KAZ). All prototypes were submitted to and passed state trials in 1959. Even though the Ob'yekt 1015B performed best, the GAZ design was selected and given the designation BTR-60P. Officially, the committee that made the decision did so because of the GAZ plant's production capabilities and experience. The main reason was that the GAZ design was the simplest and cheapest one and introduced the fewest technological advancements, which made it easier to put into mass production. BTR-60P had open-roofed crew and troop compartments, which was deemed to be a serious disadvantage. Accordingly, a new version with an armoured roof, designated BTR-60PA, entered production in 1963. This new version's capacity was reduced from 16 soldiers to 14 soldiers. The appearance of the German HS.30 APC, which was armed with a 20 mm cannon, prompted the addition of the conical BPU-1 turret. This turret, which was originally developed for the BRDM-2 amphibious armoured scout car, was armed with the KPVT 14.5 mm heavy machine gun and a PKT 7.62 mm tank machine gun. The new vehicle was designated the BTR-60PAI and entered production in 1965. It was, however, quickly replaced by the BTR-60PB, which had a better sighting system for the machine guns. Description BTR-60 was a revolutionary design for its time. It had a non-standard layout for an APC; the crew compartment was in the front, the troop compartment in the middle and the engine compartment in the rear. This meant that, while the BTR-60 did not share some of the weaknesses that other APCs had, it had several disadvantages of its own. Crew In the BTR-60, the crew compartment is located in the front of the vehicle and had a roof – unlike the troop compartment, which first received one with the introduction of the BTR-60PA. In the BTR-60P and BTR-60PA, the crew consists of a driver and a commander. The driver's seat is on the left and commander's seat is on the right. In the BTR-60PAI, BTR-60PB and BTR-60PZ, the crew consists of a driver, a commander and a gunner. The position of the driver and commander stations remained unchanged in later models. The gunner operates the BPU-1 turret, using the PP-61A optical sight. In the BTR-60P, both the driver and commander manned their positions by entering the vehicle through the sides. The BTR-60PA introduced two hatches over their