Mercury - Quicksilver Black Diamond 3-Blade Aluminum Propeller 7.8" Diameter x 7" Pitch Right-Hand Rotation 3-Blade Aluminum High-Gloss Phantom Black Finish QA3182R. Overview. There's something deeply satisfying about running a boat that feels just right - when the throttle responds smoothly, the wake looks clean, and you feel that gentle push forward without effort. The Quicksilver Black Diamond 7.8" x 7" Pitch Propeller (QA3182R) delivers exactly that kind of experience. It's simple, reliable,