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Author Topic:   Doel Fin on 18'OR?
commodore posted 08-16-2002 11:37 AM ET (US)   Profile for commodore   Send Email to commodore  
My 18' OR has a 90 HP Evinrude, under maximum HP of 150 but over minimum of 70. Performs well enough for us, but wondering if a Doel Fin or similar device would improve performance. Any comments?


bocaspiff posted 08-16-2002 03:41 PM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
I have a friend who uses one and it gets the boat on plane at very low speeds which is useful in choppy water or economical cruising. It might be the perfect accessory for your combination in light of it's $29 cost. Hope this helps.
David Ratusnik posted 08-16-2002 03:59 PM ET (US)     Profile for David Ratusnik  Send Email to David Ratusnik     
Commodore- Go with Bennett or other similar brand trim tabs. Since you are underpowered and concerned about performance tabs may be your ticket to getting up on plane and maintaining it. .03 David
bocaspiff posted 08-16-2002 04:49 PM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
Dave is right, Bennett Tabs do what they were designed to do well. However, they are problematic. I had them on my 15 Sport, 18 Outrage, and 17 Newport. All of them had problems. Bennett has a great warranty for a reason...they break alot.
Dave, do you use Bennett Tabs? Have you used a Doelfin?
my1st13sport posted 08-16-2002 07:29 PM ET (US)     Profile for my1st13sport  Send Email to my1st13sport     
i use a similar product on my 13'4 sport with a 40 hp merc. Up on plane quick,and a good investment on my size boat. This accessory works well with most size boats.
my1st13sport posted 08-16-2002 07:32 PM ET (US)     Profile for my1st13sport  Send Email to my1st13sport     
OOPS, not trim tabs, that would be overkill on my boat. I am talking about the doel-fin type products.
SSCH posted 08-16-2002 07:55 PM ET (US)     Profile for SSCH  Send Email to SSCH     
You might try Lenco electric tabs. They are easier to install and take less interior space than Bennetts since they don't need hydraulics.

The Doelfin will add drag and will lower top speed. If the fin hits under water obstructions, it may fail in a way that very adversely effects boat handling. I've heard stories about improved performance (at slow speed) planing with these fins, but have never been willing to live with the afore mentioned problems since my first Montauk. The fin I had on that boat (which had a 80hp Merc)didn't seem to help me in any way.

There are several stainless steel versions of the Doelfin sold that might be a better bet if trim tabs are too steep an investment.

Tom Byrum posted 08-16-2002 09:15 PM ET (US)     Profile for Tom Byrum  Send Email to Tom Byrum     
Forget the Doelfins. Find you another 90 Evinrude.
acseatsri posted 08-17-2002 12:44 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
2 thumbs up on the Doelfin. Installed one this year along with transom wedges on my 1989 OR18 with 150 Rude- difference is truly amazing at slower cruising speeds when in rough water. A must if you run in open water where it can get sloppy on the way home.
Wreckdiver posted 08-17-2002 04:46 PM ET (US)     Profile for Wreckdiver  Send Email to Wreckdiver     
I installed a fin on my 2000 Montauk and like it. The back of the boat is mostly filled with dive gear, so it helps to keep the boat on plane at lower speeds. It may have cut some of the top end, but ever one is usually yelling at me to slow down any way.
JOHN W MAYO posted 08-17-2002 05:39 PM ET (US)     Profile for JOHN W MAYO  Send Email to JOHN W MAYO     
I had a fin on my Merc 150 eng. Just took it off, but am about to put it back on to give it another try. I have noticed that with the fin, in a tight turn the engine appears to cavitate alot... more. When I removed it, I did not have this problem.....I am going to put it back on to see if I can tell much more diffwerence about palning at slower speeds.
bocaspiff posted 08-19-2002 08:22 AM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
I find that if I trim my motor out to run on the upper end of the RPM's, that the doelfin is completely out of the water anyway.
SSCH posted 08-19-2002 09:52 PM ET (US)     Profile for SSCH  Send Email to SSCH     

You must have had the engine set really high on the transom. Obviously, if the fin is out of the water it isn't causing drag. I'm surprised, however, that this engine setting works well on a fishing boat. I've seen high performance types run almost out of the water, but all my boats have done better with more of the lower unit in the water. There is less cavitation in turns, and better rough water performance in general.

David Ratusnik posted 08-20-2002 06:01 PM ET (US)     Profile for David Ratusnik  Send Email to David Ratusnik     
bocaspiff- I used a Doelfin on a very heavy 23' Chris Craft with 350/260 IO set up. Didn't do much for it when it ran right. Dumped the boat.

I've had Bennett tabs on my 22'OR for pushing a year. Reliability 100%, no breakdowns. Use them constantly for everything except watersports. Why, if you have them waaaaayyyyye down and start pulling someone on tube/ski and the rope is not directly behind you the boat will actually swerve hard port/starboard. Scared h*** out of me one time.

Without a tube or ski behind I love 'em. Quick out of hole and fabulous at adjusting boat with a 10/15mph cross wind. DON'T LEAVE HOME WITHOUT THEM. .03 David

bocaspiff posted 08-21-2002 07:59 AM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
Not arguing the utility of Tabs. We use them (Kiekhaffer not Bennett) on race boats all the time and they (Bennett) work well on cabin cruisers. I personally don't like drilling holes into glass and foam. There is no wood in a 17' where the tabs would have to be mounted properly. I had tabs on my 26 Mako (2-200 Yamahas) and they were essential.
My motor is mounted high. With the Doel-fin, I can turn better and not cavitate. I am not an expert but Bennett Marine is: 954-427-1400. Call their customer service representative, Mark Ordway, who I have known for 20 years and ask him how many pumps, actuators, and switches he sends out each week. I opt to not put tabs on a little boat. If the boat is running uneven, I tell the other person causing the problem to stand on the other side of the boat.
Mark Ordway posted 08-21-2002 11:39 AM ET (US)     Profile for Mark Ordway  Send Email to Mark Ordway     
I have been following this post with great interest. We monitor several boating forums, including the Classic Whaler site. We learn a tremendous amount from hearing what boat owners have to say. Most of the time we are able to provide helpful information.

Most planning hulls are designed to run lightly loaded at wide-open throttle. Unfortunately, most people do not use their boats this way most of the time. Not only do we subject our boat to "internal factors" like moving passengers, extra gear, changing fuel loads, ice and water, our boat is also subject to "external factors" such as changing water conditions, wind, current, and water depth. We would need an adjustable hull for all of the varying conditions that we experience and that is on a good day!

An option for making some of the adjustments would be by using power trim on the engine (with or without a Doelfin). This method requires using engine power to correct the hull angle. The bottom line is that you are burning fuel that you were hoping to save and likely losing speed for that given throttle setting. I must also mention that you do not have the ability to correct the boat for a listing condition. Trying to balance the load is more critical for small boats than it is for larger vessels.

Adjustable trim tabs give an operator the ability to run their boat at its most efficient angle while at the same time correcting for a list and allowing for the engine or outdrive to be "tweaked" to optimum RPM for a given throttle setting. The result is improved performance, dryer ride, improved fuel economy, reduced hull stress and reduced engine stress. Most boaters will not argue with a better and safer ride where they get increased range of travel and the possibility of increased speed for a given throttle setting.

A Doelfin is less expensive and may be the item that fits in your budget. Trim tabs will pay for themselves in fuel savings that a fin cannot create. I think you will be glad you went with trim tabs. Call me at 954-427-1400 and we can discuss all the reasons they should be Bennett Trim Tabs. I may be more biased than Tab Man may but as Technical Trainer for our Client Services Staff, I tend to get opinionated and wordy.

I have not been at Bennett Marine for 20 years but this month I did have my 18th anniversary with the company. (Can I say that sometime it feels like more than 20 years? I guess I did. ) I truly believe in our product and I believe in our company philosophies and how we treat fellow boaters. (I have to be able to sleep at night.) My goal is that we never stop treating people better than we hope to be treated.

The idea that poorly designed or problematic products need a great warranty is a concept I cannot buy. There is not a quicker way to go out of business than to build a substandard product and offer to replace it free for a long time! We are so confident in our Trim Systems that we can offer our FIVE-YEAR warranty without hesitation. Bennett Marine has been building trim tabs for 42 years. It is safe to say that a very, very, very low percentage of field returns are five years old or less. Many parts received for repair are 20 years old or older. Fellow boaters will tell you that our warranty is one of the most liberal in the marine industry often providing coverage where other companies make money. (Treat people better than we hope to be treated.)

Commodore best of luck in your search improved performance. Call me if you have a question I can help you with.


Mark Ordway
Bennett Marine

bocaspiff posted 08-21-2002 01:21 PM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
How nice is it that manufacturers pay attention to this site. Mark makes a great point and he's right the only manufaturer problem incurred by our boats were the switches, which have been redesigned. With the 17' Whaler the screws holing the mounting and ware-plates for the tabs would strip out b/c there was no wood in the transom for the screws to bite.
bocaspiff posted 08-24-2002 06:33 PM ET (US)     Profile for bocaspiff  Send Email to bocaspiff     
20 Years ago my Dad was probably the only guy in the world with tabs on a 13' Whaler. He loved that boat and so did I. My first sentence: "I wanna go by-by in the boat in the water with Dad and fish." , was inspired after a day of catching dolphin with him.
On the 15 Whaler, which also had a set of 12"x12" tabs, the boat would get on plane in its own length. Try and find any flats boat that will do that! Tabs and Whaler make sense. My posts earlier were made without merit. My Dad reminded me how much he enjoyed having them on the boat and how it made an already safe boat, safer.

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