Mercury - Quicksilver Black Diamond 3-Blade Aluminum Propeller 15.5" Diameter x 18" Pitch Right-Hand Rotation 3 Blades Aluminum Black Finish QA2014X. Overview. There's a moment every boater knows-the throttle opens, the engine growls low, and your boat surges forward, steady and sure. That's where the Quicksilver Black Diamond 15.5" x 18" Aluminum Propeller shines. It's the kind of prop that gives you confidence every time you leave the dock-smooth acceleration, steady lift, and consistent contr