Pilots who converted from the Merlin to the Griffon-engined Spitfires soon discovered that, because the Griffon engine's propeller rotated in the opposite direction to that of the Merlin, the fighter swung to the right on takeoff rather than to the left.[20][nb 4] This tendency was even more marked with the more powerful 60 and 80 series Griffon engines, with their five-bladed propellers. As a result, pilots had to learn to apply left (port) trim on takeoff, instead of the right (starboard) trim they were used to applying.[21] On takeoff, the throttle had to be opened slowly, as the pronounced swing to the right could lead to "crabbing" and severe tyre wear.[22]