Davis Instruments Doel-Fin Hydrofoil

by Davis

Product Features

• Doel-Fin improves overall performance - even on boats with well designed hulls
• Save up to 30% on fuel consumption
• Faster out-of-the-hole for happier water skiers and wake boarders.
• Maintain lower planning speeds
• Simple 15 minute installation (hardware included)

Product Description

Doel-Fin is the original hydrofoil developed by an aeronautical engineer to improve overall performance on all boats with outboard motors or outdrive units. Molded in 2 pieces of guaranteed unbreakable, high-strength plastic, each foil is designed to flex independently to absorb shock. The positive effects include greater stability, consistent planing at lower RPM, faster out-of-the-hole performance, steadier turns, higher top-end speeds and lower bow rise at all speeds.

Product Details

• Product Dimensions: 2 x 9 x 12 inches ; 2.4 pounds
• Shipping Weight: 2.6 pounds (View shipping rates and policies)
• Shipping: This item is also available for shipping to select countries outside the U.S.
• ASIN: B0014490TS
• Item model number: 440
• Average Customer Review: 4.7 out of 5 stars  See all reviews (16 customer reviews)
• Amazon Best Sellers Rank: #66,149 in Sports & Outdoors (See Top 100 in Sports & Outdoors)

Customer Reviews

Most Helpful Customer Reviews

4 of 4 people found the following review helpful:

3.0 out of 5 stars Good addition to small boat - not wihout its drawbacks, however, April 15, 2010

By 

B. Christensen "Frequent traveler, business o... (Santa Barbara, CA United States) - See all my reviews
(VINE VOICE)    (REAL NAME)   

Amazon Verified Purchase

This review is from: Davis Instruments Doel-Fin Hydrofoil (Sports)

I installed the Doel-Fins on my 11.5 foot Avon SuperSport RIB (the S3.45 to be exact). The Avon has an older 2-stroke Evinrude 30 hp motor and the Doel-Fins were easy to install without requiring a right-angle drill. I spent a LOT of time measuring and determining placement before I drilled the holes in my cavitation plate, but once I drilled the holes, the rest of the install took maybe 10 minutes at most.

The good stuff:
The Doel-Fin definitely makes a big difference in two areas - getting up on plane and staying there at lower speeds. In fact, I am now able to stay on plane at speeds as low as about 6-8 mph, which allows me to save fuel and create less of a wake while transiting through harbors. Also, prior to installing the Doel-Fin, the boat had a pretty strong tendency to bang up and down when going into a head sea (swell coming toward the boat). While I wouldn't say it was "porpoising", it was close. After installing the Doel-Fin, the ride into a head sea is much smoother and tends to stay on plane much better when throttling down after cresting a swell.

The not-so-good-stuff:

Really, just two things - 1) Definitely reduced top speed. Prior to the Doel-Fin the boat would do about 31 mph at WOT in a lightly choppy sea. After the Doel-Fin, max speed at WOT seems to be about 27 or 28 mph. This represents about a 10% reduction in top speed. Not a big deal, since I don't really operate the boat at WOT much anyway. 2) The Doel-Fin really, really catches kelp! It is very tricky to get in and around the kelp to fish or dive without snagging the Doel-Fin. When this happens, the usually procedure of reversing the prop briefly doesn't always clear the snag. I usually either have to do a quick reverse followed by a FULL THROTTLE forward push to BBBBRRRRREEEEAAAAKKKK through the kelp, followed by another quick reverse to clear the prop, or I have to shut down the motor and clear the foul by hand. The problem with the latter approach is that if I have pulled anchor, I'll often drift right back into the kelp by the time I have it cleared, which repeats the problem cycle all over again.

Bottom line, its a good addition to a small boat. I found that the fins seemed a bit large for my small motor - I wish they made a smaller size that had less overlap of the cavitation plate.

4 of 4 people found the following review helpful:

4.0 out of 5 stars Almost as Advertised, July 5, 2006

By 

R. Marshall (Jacksonville, FL) - See all my reviews
(REAL NAME)   

A fairly good product with some cautions. If you already have stabilizers, this type product has a tendency to make the boat slide around alot in the stern. If I barely use the manufacturer stabilizers it seems to make everything a lot more steady. The Doel-Fin works as advertised in that the boat definitely comes up quicker which is really great! I'm sure it takes a lot of strain off the engine and is helping my GPH on fuel, although I have not had a chance to do an actual measurement yet.
One more thing to think about. The advertisement leads you to assume it will bolt right-on. This was not quite true. Depending on how the fin plates are arranged on your prop, be prepared for some contorsions and acrobatics, not to mention some out of the ordinary tools manipulations to get it installed in the correct place. Once installed, it's great and definitely worth the money.

2 of 2 people found the following review helpful:

5.0 out of 5 stars Doel Fin works!, April 23, 2011

By 

Ulator808 - See all my reviews

Amazon Verified Purchase

This review is from: Davis Instruments Doel-Fin Hydrofoil (Sports)

Had a Doel Fin on my small 15 hp Evinrude that seemed to work well, so decided to give it a shot on my 90hp Yamaha to see if it could fix my cavitation issues. Installation was a snap and had it on in less than 15 minutes. Have been using it for over a month now and my cavitation problems are gone. I have a 15.5' Livingston and used to take forever to get it up on plane. With the Doel Fin, it jumps up on plane as soon as I give it some throttle. I feel that I have way better plane control and my boat also goes faster. I would recommend this product to anybody having cavitation issues. Would buy again if needed.