Grizzly I cruiser

The Grizzly I was a Canadian built M4A1 Sherman tank with some modifications, it had thicker, more sloping armour, had a longer range, and, most notably was fitted with Canadian Dry Pin tracks (CDP) tracks, which did not require rubber, a scarce wartime material.

History
After the fall of France, it was decided the nascent Canadian armoured divisions would be equipped by tanks produced in Canada. The result was the Ram cruiser tank, based on the chassis and running gear of the US M3 Lee; Rams were produced by the Montreal Locomotive Works (MLW) from 1941 to 1943. The M3 was succeeded by the superior M4 Sherman. The Allies agreed to standardize on the M4, and MLW began producing the Grizzly in August 1943.

Grizzly production halted when it became apparent US production would be sufficient. Instead, MLW produced the Sexton self-propelled gun Mk II. The Sexton Mk II used the Grizzly chassis, with the upper hull modified to carry the Commonwealth standard QF 25 pounder gun. The Sexton was the Commonwealth counterpart to the US M7 Priest. A small batch of Grizzly medium tank was fitted with an Ordnance QF 17-pounder for training but none saw action.

After the war, a number of Grizzly tanks, and Sexton self-propelled guns were sold to Portugal as part of the NATO military assistance program. They were retired in the 1980s.

Design
The Grizzly's suspension used 17 tooth drive sprockets and CDP tracks. In comparison, the M4 used 14 tooth drive sprockets. The CDP track was lighter and simpler than the standard US tracks and did not require rubber, which was scarce since the Japanese advance into Southeast Asia.

Some were planned to be converted into the Skink anti-aircraft tank with a turret mounting four 20 mm Polsten cannon.