A variant of the "Sentinel", AC IV with a 17 pounder.

A variant of the "Sentinel"

The Australian Cruiser tank Mark 1 (AC1) was designated "Sentinel" in February 1942. Fabrication was by Sydney's Chullora Tank Assembly Shops with serial production vehicles emerging in August 1942, the premises also being used as a testing ground. The design used existing parts where available from other tank designs, simplified where necessary to match the machining capacity present in Australia. The hull was cast as a single piece, as was the turret; a technique not used on the hull of any other tanks of the era.(rudeerude)

Australian "Sentinel"

The vehicle utilised a CMP chassis and engine produced by General Motors Canada, the rear-engined model 8446, the same chassis as used for the Canadian "Fox" armoured car. To this a welded armoured body fabricated from Australian Bullet-proof Plate (ABP-3) of 30 mm thickness to the front and 11 mm to the sides and rear was fitted. The vehicle was completed by a welded turret with 30 mm all-round protection similar in design to that of the Crusader tank. The armament consisted of a QF 2 pounder Mk IX gun and a coaxial .303 inch Vickers machine gun.
A pilot model of an armoured personnel carrier with an open-topped hull and without a turret was also built.