Like Australia, Canada also found itself without much of an armored corps (or facilities to produce such systems) at the start of hostilities in World War 2. And much like the Australians, the Canadians were forced to rely on the tank systems as brought to them by the British and the Americans. Sherman production was full steam down in America and the Canadians elected to produce a local variant of the M4A1 Sherman model in their own backyard. However, the American production facilities proved to have quite a reach and American-made Shermans were flying off the assembly lines ready for all available takers. As such, the Grizzly program proved a short-lived venture, but it nonetheless offered the Canadians a home-grown product and a taste of new-era armor design and production standards associated with them.
The Grizzly maintained its general Sherman appearance throughout, complete with its high profile and rounded armor edges. The Grizzly did differ from its M4A1 origins by having CPD-type tracks, thicker armor protection and an improvement of an 20 additional miles of range. The Grizzly retained the Continental R-975-C1 9-cylinder radial gasoline-fueled engines that provided for an output of 353 horsepower while at 2,400rpm. Performance was equally similar with a top speed of 24 miles-per-hour (achievable in bursts) and a maximum range of 120 miles. Armor measured up to 2.95 inches at its thickest.
Primary armament was a 75mm high-velocity M3 L/40 main gun mounted in a fully-traversable turret. Secondary armament included the 12.7mm Browning heavy machine gun to make short work of low-flying aircraft, lightly armored vehicles or enemy infantry. Further anti-infantry defense was tackled by the co-axial .30-06 caliber machine gun fitted to the turret (next to the main gun) and a bow-mounted .30-06 caliber system in the front right hull (on a flexible mount).
Like the Sherman before it, the Grizzly featured a standard operating crew of five personnel. This included the tank commander, loader, gunner, bow-gunner/co-driver and the driver. The driver and bow gunner sat in the forward left and right positions of the forward hull respectively. The gunner, loader and tank commander each took a place inside of the turret.
It was originally intended that some 1,200 Grizzlies be in service come early 1944 but this plan eventually came to naught when the American M4 Sherman model became an all-too available commodity for Canadian, British and Australian consumption. The Canadian War Office eventually nixed the plan for the locally-built Shermans and decided to accept the American-produced ones instead.
Montreal Locomotive Works was tapped to produce the Grizzly, with production beginning in August of 1943. Upon the decision handed down by the War Office, production instead switched over to the valuable 25-pounder SP gun. Despite the official cancellation of further Grizzlies, the first 23 completed systems were still delivered in October of 1943. This was eventually followed by another 165 production examples bringing the total to 188 units.
The Grizzly I Cruiser tank program was officially completed in January of 1944. In the post-war years, some 55 Grizzlies were shipped off to Portugal and many thereafter became collector's items. The Grizzly was also spawned into a makeshift armored personnel carrier noted with the Grizzly APC designation. Portugal also received approximately 40 of these systems and used a handful in driver training exercises. The fate of the armored personnel carriers found them sold for scrapping at the end of their useful run.
Amazingly, the Grizzly class of Sherman tanks represent some of the more numerous types of Shermans still running today.