This StingRay hydrofoil stabilizer for outboard motors is the XR4 Senior model SR-XR4-1 in black, intended for 40–300 HP motors. It is mounted on the motor’s anti-ventilation/cavitation plate and creates extra lift, allowing the boat to plane faster and maintain plane at a lower speed.
The XR4 has lift level 3 – Maximum and downward-curving wings that direct water closer around the propeller. The design helps lower the bow angle, improve acceleration to plane, and increase stability while underway. It can also reduce porpoising, chine walking, cavitation, and ventilation, while providing better forward visibility because the bow comes down sooner.
The hydrofoil is made of plastic with low water friction. The black graphics are scratch-resistant and fade-resistant. The model is suitable for, among others, heavy runabouts, center console boats, pontoon and tritoon boats, as well as boats used for water skiing, tubing, or wakeboarding. The more controlled planing can also contribute to a smoother wake and reduced fuel consumption.
Installation is performed by drilling two holes and using two bolts. The hydrofoil is pushed as far forward as possible on the anti-ventilation/cavitation plate with the graphics facing up, after which the top holes are used as a drill template. Drill using a 1/4" drill bit, corresponding to approx. 6.35 mm. The kit includes 2 nylon lock nuts, 2 stainless steel 1/4-20 × 1" bolts, and 2 stainless 1/4" flat washers.
Installation requires a Phillips screwdriver, a drill with a 1/4" bit, and a 7/16" socket and ratchet. During installation, the motor must be turned off, the kill switch disconnected, and the gear selector in neutral. After mounting, the propeller must be turned slowly by hand to ensure it does not touch the hydrofoil.
Compatibility assumes an outboard motor of 40–300 HP with a suitable anti-ventilation/cavitation plate that can be drilled, as well as sufficient clearance between the hydrofoil and the propeller. The product is manufactured in the USA and is covered by a 1-year warranty for the original purchaser against significant material and manufacturing defects in accordance with the warranty terms.
Key FeaturesFor outboard motors from 40–300 HP
Lift level 3 – Maximum
Faster transition to plane and planing at lower speed
Reduces bow angle, porpoising, chine walking, cavitation, and ventilation
Downward-curving wings direct water closer around the propeller
Black plastic with scratch- and fade-resistant graphics
Mounting with 2 drilled holes and 2 bolts
1/4" drill diameter and mounting hardware included
Model SR-XR4-1
