Davis Whale Tail XL StabilizerThe Davis Whale Tail XL is an aluminum stabilizer and ski boat fin. With this stabilizer, you can improve the performance in any I/O or outboard motor. The Whale Tail XL extends out behind the propeller to utilize prop wash energy which is normally lost. Whale Tail transforms this energy into lift for immediate response when the throttle is applied. The Whale Tail XL also flattens the wake for water skiing, creating positive, skin-free turns. Use the Whale Tail XL year-round in freshwater or saltwater to improve performance of any boat!Features: Unique hydrodynamic design; Stabilizes bow-light boats; Pops skiers up in less time; With bow lowered, visibility is improved-and safety; Smooths out ride in rough water; Reduces porpoising and cavitating; Increases top speed and fuel savings in most applications; Marine-grade aluminum with durable anodized finish; The Davis Whale Tail XL installs in 15 minutes and includes stainless steel hardware!How to Install a Davis Whale Tail XL StabilizerThe Whale Tail XL mounts on the anti-cavitation plate of all inboard/outboards and outboards. Locate the anti-cavitation plate (the horizontal plate just above the propeller). Slide the whale Tail onto the flat side of the anti-cavitation plate, preferably its underside.; Note: Leave no space between the cut out of the Whale Tail and the back of the anti-cavitation plate. On Volvo inboard/outboards, mount Whale Tail on top.; Clamp the Whale Tail in place. Using a 1/4" (6.5 mm) drill bit and the holes in the Whale Tail as a guide, drill four holes through the anti-cavitation plate. ; On Volvo, drill through the hollow exhaust anti-cavitation plate.; Note: if the holes in the Whale Tail do not work on your anti-cavitation plate, drill new holes in the Whale Tail for maximum strength.; Insert a 1/4" (6.5mm) bolt in the hole just drilled, the head of the bolt on the Whale Tail side.; Install washer and nut and tighten snugly. Do not over-tighten.; On Volvo, longer bolts will be required: 1/4 x 2" (6.5 mm x 5.4 cm).; Click to Download Davis Whale Tail XL Installation Instructions