Mercury - Tempest Plus 3-Blade Stainless Steel Propeller 14.6" Diameter x 21" Pitch Right-Hand Rotation 3-Blade Stainless Steel Polished Finish 8M0151382. Overview. There's nothing like that feeling when your boat launches perfectly onto plane smooth, steady, and full of power. The Mercury Tempest Plus 14.6" x 21" Pitch Propeller (8M0151382) captures that magic. It's for boaters who know the difference between "good enough" and "just right." You'll feel it every time you hit the throttle the qui