DAVIS Doel-Fin User 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)

1 2

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. This creates a feel­ing like "power steering", smoothes out the turns and reduces cavitation in tight turns.

Q. How about pulling water skiers?

Faster out-of-the-hole times and lower planing speeds make for happier skiers. Wakeboarding, tubing and
slow speed water skiing is made easier, too. Beginning water skiers, especially children just learning to ski,
will appreciate Doel-Fin’s slow speed planing performance improvement.

Q. Can I use it with power trim?

Doel-Fin enhances the effects of power trim. Your boat will respond quicker to changing trim angles, making
power trim more effective.

Q. How do I know it will fit my motor?

Doel-Fin fits all outboard and stern drive motors from 5 horsepower, except Volvo Penta®outdrives.

Q. How do I know Doel-Fin is working on my boat?

There will be no doubt! An instant increase in performance is unconditionally guaranteed or your money
back. You can expect fuel savings from 10-50%, with the average being around 30%.

3465 Diablo Avenue, Hayward, CA 94545, U.S.A.

Phone [phone] • Fax [phone]

[e-mail] • www.davisnet.com

00440.031, Rev. B March 2012