After the fall of France, it was decided that Canada should manufacture its own tanks, rather than be supplied from the UK or with US-built tanks, for the amoured divisions that were being formed. For speed of introduction, the native design would be based on the US M3 Lee Medium Tank. The limitations of the M3 design led to extensive reworking of the design to give the Ram cruiser tank. This was produced at the new factory of Montreal Locomotive Works. The Ram was suitable for training but the M4 Sherman which quickly followed the M3 design was superior and the Ram production line was switched over to Grizzly production in August 1943 Production of the Grizzly was halted as US tank production would be sufficient for all the Allies and the production line was switched instead to the Sexton self-propelled gun Mk II. The Sexton was designed after the US M7 Priest which used the M3 and then M4 chassis. The Sexton Mk II used the Grizzly chassis, the upper hull modified to carry the Commonwealth standard QF 25 pounder gun instead.
The Grizzly differed in the suspension from the M4, having a 13, instead of 17, tooth idler and CDP tracks.
Some were planned for conversion to the Skink anti-aircraft tank with a turret mounting four 20 mm cannon.
Following the war, a number of Grizzly tanks, and Sexton self-propelled guns were sold to Portugal as part of the NATO military assistance program where they served until finally being retired in the 1980s.| Grizzly I | |
|---|---|
| Type | Medium tank |
| Place of origin |  Canada |
| Service history | |
| In service | 1943-45 (Canada) 1954-1980s (Portugal) |
| Used by | Canada Portugal |
| Wars | Second World War |
| Production history | |
| Designed | 1941 |
| Manufacturer | Montreal Locomotive Works |
| Produced | 1943-44 |
| Number built | 188 |
| Specifications | |
| Weight | 29.91 t (30 tonnes) |
| Length | 19 ft (5.816 m) |
| Width | 2.626 m |
| Height | 2.997 m |
| Crew | 5 (Commander, gunner, loader, driver, co-driver/hull gunner) |
| | |
| Armour | 75 mm |
| Main armament | High Velocity 75 mm M3 L/40 gun |
| Secondary armament | 2 x .30-06 machine gun |
| Engine | Continental R-975 9-cyl radial gas 400/340 hp (298/254 kW) |
| Suspension | Vertical volute spring |
| Operational range | 193 km |
| Speed | 24 mph (38.6 km/h) |
