In May of 1940, the Royal Canadian Air Force Marine Section had begun a testing program centered around a lone 40-foot armoured target boat as designed by the British Power Boat Company. This was the beginnings of the RCAF's expansion into the sea-going service and its fleet of "glamour boats". By July of the same year, a second and much larger boat at 70-feet was accepted for testing off of Canadian shores. The 70-foot boats were constructed with exotic African mahogany wood, 1,350 horsepower Rolls-Royce Merlin engines, and had a top speed of 45 knots.
40-foot armoured target boat
70-foot high speed launch
Upon completion of the testing and trials, a total of 12 ATBs and 6 HSLs were ordered from both British and Canadian manufacturers. These 18 boats were supplemented by a further 12, 71-foot motor torpedo boats acquired as surplus from the United States Navy. Of the six HSLs, two were assigned to Eastern Air Command, Nova Scotia, and four went to Western Air Command, Vancouver. While the HSLs were equipped with a limited anti-submarine capability in the form depth charge racks, they were never used in aggression against any enemy vessels. They were after all, procured to serve in the role of sea rescue.
As the war ended in 1945, the ex-U.S. Navy MTBs were returned as these were lend-lease items. The HSLs continued their service in the RCAF, and were not decommissioned until 1952.