Canadian Army Develops New Baseplate For Mortar
Canadian Army Journal, Vol. 9, No. 1, Jan 1955
A News Report By The Directorate Of Public Relations (National Defence)
The Canadian Army has solved a problem which has baffled military researchers for years. Army Headquarters said it has developed a lighter, more durable and cheaper medium mortar baseplate which has passed all tests with flying colors. It is now available for issue to infantry units. The new, 25-pound, circular baseplate is made of high-grade aluminum alloy and can be produced for $65, about 50 per cent. cheaper than the steel plate now in use. Production has been carried out by the Aluminum Company of Canada, Limited, at its Kingston, Ont. plant. The baseplate is adaptable for use with both the U.S.-built 81-millimetre mortar and the British-built three inch weapon. Extensive tests resulted in excellent reports on the new baseplate. Research has gone on since 1949 when the Directorate of Armament Development was first assigned the job. The aluminum plate has been tested on every type of surface – mud, sand, turf, solid concrete, rubble, frozen river beds and thick lake ice, as well as off concrete with the centre unsupported. In all these tests the hammer forged disc withstood the 45,000 pounds-per-square-inch pressure exerted on it each time the mortar was fired. The plate has been subjected to temperatures as low as 50 degrees below zero and hundreds of rounds fired from the mortar. Super charges were used to boost the pressure thrust considerably but the plate showed no signs of cracking or breaking. Biggest drawbacks of the steel baseplate were its cumbersome weight (40 pounds) and its tendency to crack or break after rough or prolonged usage. Seeking to overcome these drawbacks, the Army took its problem to the Department of Mines and Technical Surveys. This department put its experts to work on the problem. Before long they had met the rugged standards required by the Army for this new and unique design of mortar baseplate. Research into the use of a still lighter metal, magnesium, is continuing at the Department of Mines and Technical Surveys.
To many readers, this baseplate will be most recognizeable as that used with the following weapons: