Whale tails on a motor, does it really help?

Joined
Mar 19, 2009
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I have been talking with several people at a sporting goods store where I used to work about the the fins that you can put on a motor that supposedly give the boat a better hole shot, eliminates porpoising, and I have even been told that it may add up to 5-8 mph to the top speed. Are they serious or is this just another attempt to take a fisherman's money??
 

Sixmark

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Jul 11, 2010
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Re: Whale tails on a motor, does it really help?

OK I needed a good laugh and I just got it reading this, no offense to you intended.

a prop may gain you a better holeshot, but unless they are going to be hinged and start flapping at a high rate of speed, then I don't see fins giving you a better holeshot

they are generally supposed to help you plane out better, and that's about it, and they don't work in all applications either, if there are attributes about you boat that you would like to change then please feel free to address them specifically, fins are not a magic cure all for performance.
 

jtexas

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Re: Whale tails on a motor, does it really help?

They can be a big help in getting underpowered boats up on plane, I've seen it a couple times.

Porpoising is caused by overloading/poor weight distribution and/or underpowering, so I bet it would help with that -- although adding a hydrofoil instead of addressing the root cause is sub-optimizing the set-up, and failing to realize the boat's full potential.

If it helps your top end speed, it means your motor is mounted too low -- it should be out of the water at WOT anyway.
 

jonesg

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Feb 22, 2008
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Re: Whale tails on a motor, does it really help?

It made a huge improvement on my boat but it was in dire need of a transom job at the time and I haven't tried it since I replaced the transom.

I suspect the transom was buckling under load because the splashwell cracked open and I decided to gut it out and replace the transom/stringers.

As I said I haven't put it back in the water again yet so...I hope to be able to remove the doel fins.
 

JimS123

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Jul 27, 2007
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Re: Whale tails on a motor, does it really help?

I'm laughing too....LOL. Search this topic and you'll get a lot of information and a lot of misinformation too.

Better hole shot?....Absolutetly. That's what they were invented for. Changing to a new prop with a different pitch may do that too, but for a lot more money and not without other affects as well.

Porpoising improvement, maybe. Top speed increase...maybe...but not 5-8. Better handling - for sure.

The caveat is that they don't work on all boats. Give me a stern heavy boat, and I won't be without one.
 

JimS123

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Re: Whale tails on a motor, does it really help?

They can be a big help in getting underpowered boats up on plane, I've seen it a couple times.

It works much better on OVERpowered boats that have to much weight on the transom.

If your only problem is being UNDERpowered, your best bet would be to change to a lower pitch prop.
 

Scottycat

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Jun 20, 2010
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Re: Whale tails on a motor, does it really help?

I put it on my last boat.
It helped me get on plane a little faster.

I might add it if I pulled skiers or ran heavy.

Adding to what the fellas said, it depends on your boat and motor.
-Scotty
 

AEROCOOK

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Jul 28, 2004
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872
Re: Whale tails on a motor, does it really help?

I like mine, I have it on my 16 foot aluminum bowrider with a 1988 110 hp Johnson. The boat is rated for a 90 hp so yes I am overpowered, but not overweighted as the 90 and 110 weigh the same. I had the hydrofoil on the motor 2 summers ago and the only disadvantage I noticed was that that it made my steering very hard to one side. Last summer I decided to take it off to see if it made much difference and I found that the steering didnt pull any more but boat would porpoise unless I was trimmed all the way in and I also took longer to get on plane. This summer I put it back on which stopped the porpoising and greatly improved the time to get on plane I also adjusted the trim tab to neutralize the steering and now Im happy and intend to leave it on.
Others may have differing opinions but on my package it's made a world of difference.

BTW not to sound naive, but whats the difference between a good hole shot and getting on plane fast?
 

TahoeQ4Pilot

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May 23, 2009
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Re: Whale tails on a motor, does it really help?

Actually, I put a hydrofoil on my lower unit, it would be useless putting it on my motor. :D

But the good news is that it helped my porposing and gets me up on plane quicker. So, at least for me, it really helped. YMMV
 

jtexas

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Re: Whale tails on a motor, does it really help?

...
BTW not to sound naive, but whats the difference between a good hole shot and getting on plane fast?

it's like the difference between amnesia and forgetting everything.
 

archcycle

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Sep 21, 2009
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647
Re: Whale tails on a motor, does it really help?

You can keep on plane at way lower speeds. Also on my light 16' in heavy chop it keeps the prop underwater preventing it's attempts to overrev

Top speed? No...... Increased drag = less speed?

I had a whale tail on my last motor and it dropped my top speed from 37 to 25 but it turned like it was on tires.. needless to say that came off

Go for the walmart fins, they angle up so when you get going they mostly get out of the water

edit: the whale tail/hydrofoil said something like 'motors 40hp-300hp' haha that's an unlikely range
 

dbkerley

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Apr 6, 2009
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443
Re: Whale tails on a motor, does it really help?

It works much better on OVERpowered boats that have to much weight on the transom.

If your only problem is being UNDERpowered, your best bet would be to change to a lower pitch prop.

I couldn't agree more with this one. I can tell you from experience that an HPV-160 with an overgeared 135 on the back and 40 gallons in the livewells plus full fuel tank and dual 1000cca batteries will get up on plane alot faster after putting the tail on and with the right prop it will ride on the tail with the right water and eye goggles.
 
Joined
Oct 22, 2007
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Re: Whale tails on a motor, does it really help?

add up to 5-8 mph to the top speed.QUOTE]

That part is pure malarky. First off, it the engine height is correct fins will be out of the water once on plane - where they can't possibly have any effect. If they're in the water or just skimming the surface it's more drag - which equals lower top speed.

Get on plane quicker - probably. It helps my boat.

Plane at lower speeds - probably. Again, it helps my boat.

Reduce porpoising - maybe a little, or maybe not. If the engine height just happens to be such that the fin is skimming the surface on plane then when the bow tries to come up water pressure will tend to push up on the rear of the fin, which should reduce porpoising somewhat. Trim tabs should be a lot more effective for this though (but also more expensive).
 
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