Outboard Stabilizers question

zippy83

Chief Petty Officer
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Jan 1, 2013
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491
Previously I replied to a thread that was over 1 1/2 years old and was advised to open a fresh one. so here it goes

First time boat owner. I have a 1995 16' Lowe aluminum boat with a 1978 50HP Mercury Thunderbolt outboard. No power trim. From what I heard I need to make sure that SE Sport? High Performance Hydrofoil would work with the setup I got. My question is as simple will it help the outboard perform better? Other than better handling what else do I gain with this extra fin?

Thanks
 

Home Cookin'

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May 26, 2009
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Re: Outboard Stabilizers question

The simple answers to the two questions are "no" and "nothing." Don't add a fin to the motor or tabs to the boat; yours is a basic rig.

I assume it's a console rig and your 50 HP is within capacity?

Trim the boat by setting the motor in the best hole on the bracket then adjust by moving crew and gear around. Consider rigging it with fuel and battery towards the middle (amidships) rather than stuffed up under the stern. For safety, err on the side of bow up.
 
Joined
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Re: Outboard Stabilizers question

my understanding is that fins and tabs were designed to help get a boat on plane faster by lifting the rear of the boat at slow speed. if it doesnt lift the boat it makes a good water brake to slow the boat until it gets enoght prop speed to help it jump on plane. (not realy sure what you mean by handling)
there are people who swear they work and people who swear they dont but most of us agree that its all to do with the set up of a boat if something works or not. setting the boat up by moving weight around and setting the tilt pin in the correct slot is the best advise (as you move weight then you will affect where the pin needs to be) only when you have hit the limits of what you can move or where the pin goes do you need to consider something else and to be honest a trim and tilt would be where i would consider putting my money.
a fin on a small boat may have more downsides than any possible gain as the boat should be easy to get on plane due to its weight.If the motor is not set at the right height the fin will act as a drag and on a old motor the fin puts a large force on the cavatation plate that may cause it to snap off. trim tabs are better but it still wont be no where near as good as tilt and trim.
 

Chris1956

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Mar 25, 2004
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Re: Outboard Stabilizers question

That aluminum boat and motor are real lightweight, compared to an I/O powerplant. I doubt a whale tail will do anything positive, and it could have a negative impact on performance.
 

Home Cookin'

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Re: Outboard Stabilizers question

Glenn I think you're right about tabs, but they are effective on larger or heavier boats than his. True, some people put them on small boats and notice a difference; some people put spoilers on Corolla's. It's not worth the money or trouble.

never heard anything good about fins, and not that I'm one to worry much about looks of a boat on a trailer, but they look dumb to me.

Power tilt is the best device for a small boat and motor, especially if you boat in shallow water. Can't say it's worth adding to a 1978 motor, though. Growing up we carried a couple different size sticks, and took great delight in trimming our outboards with our summer reading books!
 

ondarvr

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Apr 6, 2005
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11,527
Re: Outboard Stabilizers question

Copy and pasted from last weeks thread on the same subject.




There needs to be a sticky on foils and tabs indicating what each will and won't do.

The two are NOT designed to do the same thing, at least not in the same way, although the marketing makes you think they may. There is some overlap in the results though.

Tabs become a tunable (in some cases) extension of the hull, depending on how they are adjusted they can help get on plane faster, allow you to plane at a lower speed, stop porpoising, improve ride at speed, improve rough water ride, level the hull on plane, plus other things. They do this by pushing down on the water behind the transom where they can get better leverage.

A foil does one thing when used correctly, it allows you to raise the motor higher than you could without it by preventing the prop from sucking air…..that’s it. People often say they are of no value, because if they were they would come stock on motors…..well they do come stock, virtually every motor comes with an anti ventilation plate, the foil is just an extension of the stock one, similar to the tabs being an extension of the hull.

The term foil is also misleading, the foil shape has little to do with how it works, a flat sheet of aluminum will do the same thing (just like the stock AV plate).

To be used correctly a foil should not be dragging in the water at speed, this is where all the negative comments and results come from. With the foil dragging in the water on plane it may lower the top speed, cause odd cornering, and on some hulls create a scary situation. On an outboard you can raise the motor and possibly improve performance with a foil. By raising the motor the motor has less leverage on the hull so it reduces bow rise, being higher the drag from the lower unit is also reduced, this may increase top speed plus increase mileage. The reduced leverage on the hull can also reduce poroising at speed. These improvements aren’t guaranteed, they are only possibilities if you do the work of raising and lowering the motor to fine tune it, in the end you may also need to change the prop for best results.

On an I/O you can’t raise the motor, so there is a good chance you will experience one or more of the negative issues I talked about earlier when the foil drags in the water. So if you like it fine, if it does funning things and you don’t like it, don’t use it. It may also be a trade off of good and bad.

On an outboard a foil may not be the best way to achieve these results, and it may not help at all, it is very dependent on the exact hull, motor, prop, loading of the boat and how it is used. Tabs can typically make improvements on just about any hull, some hulls may need them to perform well at all, and others may do quite well without them, but still improvements may be seen with them.


Now back to the OP’s question. Leave it off and try it, some aspects of the performance may improve and some may decrease, you decide if it works for your situation or not. Tabs will probably make noticeable improvements in several areas with no negative effects.
 

zippy83

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Jan 1, 2013
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491
Re: Outboard Stabilizers question

Thanks Guys,

I was just thinking out loud. I think I will pass this time on this ide!!!
 
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