StingRay XR4 Senior hydrofoil in gray is a stabilizer for 40–300 hp outboard motors. It is mounted on the engine's cavitation plate and is designed to create maximum lift, allowing the boat to plane faster and stay on plane at lower speeds.
The XR4 has lift level 3, which is the series' maximum lift category. The downward-curved wings concentrate water flow around the propeller and help reduce the bow's lift angle, improve acceleration onto plane, and stabilize the boat while underway. The design can also reduce porpoising, chinewalking, cavitation, and ventilation. The ability to keep the boat on plane at lower speeds can contribute to lower fuel consumption.
The hydrofoil is made of plastic, which reduces friction and drag in the water. The gray surface features scratch-resistant, fade-proof graphics. The model is suitable for powerboats, pontoon and tritoon boats, and for towing water skiers, wakeboarders, tubes, and inflatable boats.
Installation is carried out using two through-holes in the engine's cavitation plate. The hydrofoil is pushed as far forward over the plate as possible with the graphics facing up, after which its existing holes are used as a drill guide. A 1/4" drill bit is used, along with two 1/4-20 × 1" bolts, flat washers, and nylon lock nuts. For installation, a Phillips screwdriver, drill, and 7/16" socket with a ratchet wrench are required.
After installation, the propeller must be turned slowly by hand to verify that there is clear space between the propeller and the hydrofoil. During installation, the engine must be turned off, the kill switch disconnected, and the gear in neutral. Any visible flow marks around the holes may stem from the molding process and do not necessarily affect the product's strength or function.
The hydrofoil is made in the USA and has a one-year warranty for the original purchaser against material and manufacturing defects, provided that proof of purchase is available. The warranty assumes correct installation, use, and maintenance.
Key featuresFor 40–300 hp outboard motors
Lift level 3 with maximum lift category
Helps the boat plane faster
Enables planing at lower speeds
Reduces bow lift angle and improves stability
Can reduce porpoising, chinewalking, cavitation, and ventilation
Downward-curved wings concentrate water flow around the propeller
2-hole drill mounting on the engine's cavitation plate
Gray plastic with scratch-resistant and color-fast graphics
Model SR-XR4-3
