Instruction Manual

15-Minute Installation

Required tools: Drill motor, 1/4" (6 mm) drill bit, Phillips-head screwdriver, 7/16" (11 mm) box wrench or

adjustable wrench.

1. Slip each Doel-Fin Hydrofoil over the cavitation plate directly above your propeller. Each foil is labeled with

an arrow, "TOP/TO BOW". Use each foil, carefully placed symmetrically, as a drilling template. Drill both

1/4" (6 mm) holes through the foil. The plate can be drilled from above or below, depending on available

room for the drill motor. In some instances, a right angle drill chuck may be needed.

2. Remove each foil and clean up the plastic and metal shavings. Slip each foil onto the cavitation plate

again and insert fasteners supplied (the nylon locking nuts go on top). Tighten snugly. Do not over tighten.

Sealant is not required although it can be used.

#440 black

#441 white (discontinued in 2007)

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#440 black #441 white (discontinued in 2007) 15-Minute Installation Required tools: Drill motor, 1/4" (6 mm) drill bit, Phillips-head screwdriver, 7/16" (11 mm) box wrench or adjustable wrench. 1. Slip each Doel-Fin Hydrofoil over the cavitation plate directly above your propeller. Each foil is labeled with an arrow, "TOP/TO BOW". Use each foil, carefully placed symmetrically, as a drilling template. Drill both 1/4" (6 mm) holes through the foil.
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Top Questions Answered… Q. How does Doel-Fin work? It uses the same principle as airplane wings. Water flow over the wing creates lift in the stern and compensates for motor weight. Doel-Fin will "calm the boat down" in rough water and eliminate the bow-high position that is common when accelerating—a dangerous slow speed characteristic of most boats. Q. Does Doel-Fin affect steering? A positive effect is enjoyed due to the increased stern lift compensating for motor weight.