What does a whale tail do?

[oldrudedude]

Yes, I have heard the manufacturers' claims. Better hole shot, plane faster, better cornering, bla, bla, bla....

I would like to hear what changes actually happened to handling and performance after people installed them.

The reason I am asking: My '71 50hp 'rude, with manual trim, had one on when I bought it. It is pushing a 14.5 ft Crestliner runabout. I left the whale tail on, but I am wondering what changes I can expect if I take it off.

 

[Barnacle_Bill]

Re: What does a whale tail do?

On some boats it does help and on others it doesn't. Take it off and try it. Make sure the boat is loaded evenly as possible. Try different positions on your trim. You may like it even better. You can always put it back on.

 

[Knightgang]

Re: What does a whale tail do?

It is supposed to act similar to trim tabs, be keeping the boat even and level when getting on plane, thereby planing faster...

I have heard some say that it makes the boat hard to turn... But like bhile said, take it off and try it, if you do not like the results, put it back on...

 

[tmcalavy]

Re: What does a whale tail do?

It gives the motor/stern more lift, due to the wings. Helps it plane quicker if you have the boat load balanced. Costs you some top end, but not much and makes the boat doggier/slower in turns due to more drag. If your outboard is a good match for your boat and you have the boat loaded/trimmed correctly, you probably won't need trim tabs or a whale tail...but I'm sure others will argue the benefits of both. Only you can decide whether they are right for your rig...compare performance with and without.

 

[Silvertip]

Re: What does a whale tail do?

Look at it this way -- if these devices were all they are cracked up to be every engine manufacturer would have them built into the motor from the "git-go" or at least offered as a factory option. They are currently an after market item.

 

[ondarvr]

Re: What does a whale tail do?

What the manufacturer claims, what people think they do and how they should be used, are frequently much different. Plus people compare them to tabs, which at first seems correct, but they are very different tools that are designed to do different things.

"If" your boat can use one, it still needs to be setup correctly or you may experience some the negative effects they may cause.

 

[oldrudedude]

Re: What does a whale tail do?

Thanks for the responses. I was hoping to hear for someone who actually installed/had one on their boat so they could tell me what changes they experienced.

I am wondering why the whale tail was installed on my boat. The PO used it primarily for fishing, so not much need for fast hole shot.

There is currently only 2 positions on the trim that I use. The third hole for flat water and the forth hole for everything else. I access the conditions before I go out and set the trim accordingly. The underway trim is done by changing the weight distribution.

My boat handles well but has a top end of only 25mph (by GPS). That seems rather low for a 50hp in good condition and tune, pushing a 14.5ft fiberglass. The boat is rated for 60hp max.

Next time I'm out I will take off the whale tail and see what the changes are.

 

[Boss Hawg]

Re: What does a whale tail do?

Thanks for the responses. I was hoping to hear for someone who actually installed/had one on their boat so they could tell me what changes they experienced.

I am wondering why the whale tail was installed on my boat. The PO used it primarily for fishing, so not much need for fast hole shot.

There is currently only 2 positions on the trim that I use. The third hole for flat water and the forth hole for everything else. I access the conditions before I go out and set the trim accordingly. The underway trim is done by changing the weight distribution.

My boat handles well but has a top end of only 25mph (by GPS). That seems rather low for a 50hp in good condition and tune, pushing a 14.5ft fiberglass. The boat is rated for 60hp max.

Next time I'm out I will take off the whale tail and see what the changes are.[/

QUOTE]

Every member here can talk all day about experiences with, without but you just stated the ONLY way to tell about the pros/cons of one on your boat

 

[steelespike]

Re: What does a whale tail do?

We had 2 whale tails they were very effective boats planed easier stayed on plane at less power and the bow stayed down better.My sister and mother wre very short so leveling the boat a little helped see over the bow.
There is no doubt if the setup isn't right they will slow the boat and can cause strange handling.Usually a tail is masking at least partly a poor settup.
Unfortunately most little boats have a battery and 2 gas tanks in the stern.
I put a 12 gallon tank in the bow of my mothers boat
Today I would get something like smart tabs.
More effective and done right won't sap speed.
You may not like all the changes in your boat but get a description back to us and we can make some suggestions.I would think 30 to 35 should be possible.

 

[Bifflefan]

Re: What does a whale tail do?

Yes, I have heard the manufacturers' claims. Better hole shot, plane faster, better cornering, bla, bla, bla....

I would like to hear what changes actually happened to handling and performance after people installed them.

The reason I am asking: My '71 50hp 'rude, with manual trim, had one on when I bought it. It is pushing a 14.5 ft Crestliner runabout. I left the whale tail on, but I am wondering what changes I can expect if I take it off.

If the effect is anything like my 16 footer, when i removed mine and laid a little gas to her the bow stood up so high i couldnt see of it. Also i had to go quite a bit faster to get on plane and to stay on plane. I think its was around 22 MPH. Didnt really have time to look as i had to stand up to see over the bow. I will also add that the comming off plane quickly will cause the wave to come over the stern into the motor well. I had to watch it and adjust my speed accrodingly when slowing down.
With the tail on i can plane at around 12 to 13 MPH And i can see over the bow all the time. No problems coming off plane and it handles alot better.

Every boat is different tho, try yours with out it and see if you like it.

Personally i hate mine without it.

My 22 does great without one and i wouldnt consider ever putting one on.

 

[ondarvr]

Re: What does a whale tail do?

What can a fin do?

When used correctly it allows you to raise the motor, this results in the other benefits, higher top speed, less bow rise, better mileage, possibly less porpoising, different prop, etc.

It should be out of the water at speed, if it drags in the water you may see a slower top speed and odd handling.

There may be some benefit from it being in the water at low speed to get on plan, but that?s not really where the big gains are.

 

[ondarvr]

Re: What does a whale tail do?

I forgot to say, there's no good way to tell if a foil will do anything to help or hurt before you actually try to set it up correctly.

It takes about ten minutes to pull it off, so try it and see what happens, you can also try to make some adjustments to take advantage of what it can (may) do.

 

[oldrudedude]

Re: What does a whale tail do?

Your comments are welcome and appreciated.

I have NOT noticed where the whale tail rides at WOT. Should it ride at or near the surface? The anti cavitation plate of the engine is set level with the lower edge of the boat skeg (I believe that is the recommended position). If the tail does not come to the surface at WOT speed, Is it because the trim is set too high, because the boat is too heavy at the stern, or because the engine is not producing enough forward thrust to lift it out of the water?

I have taken the tail off so I can test without. I am now waiting for a good weather day so I can take the boat out.

 

[ondarvr]

Re: What does a whale tail do?

If the foil isn't out of the water at WOT the motor needs to be raised, that's the fine tuning part of using one.

 

[ondarvr]

Re: What does a whale tail do?

If the foil isn't out of the water at WOT the motor needs to be raised, that's the fine tuning part of using one.

 

[oldrudedude]

Re: What does a whale tail do?

I was finaly able to take the boat out last week to test it without the whale tail.

I was able to get almost 5mph more on the top end. Cornering and handling seemed as good or better without the tail. I had to trim the motor "in" one more position. That is not a problem. Without the tail it is on the center position.

I think the anticavitation plate now rides at the surface. It is difficult to tell because there is a lot of water spraying out from the junction of the LU and the midsection. This obscures the view of the anticav plate.

I think I will leave the tail off for now. It doesn't seem to provide any advantage to my present setup. This motor has only one set of bolt holes on the transom bracket, so changing engine height is not straight forward. I will mess with the tail more in the spring. Maybe try it on my other rig.

Tomorrow is likely the last day boating for me before the snow stays. I think I will let my dog drive while I sit back and enjoy.

 

[oldrudedude]

Re: What does a whale tail do?

I had the boat out today without the tail. My wife wouldn't let me take the dog because she wanted him to stay home to make some phone calls and do some steno work for her. I had to drive the boat myself. I am feeling the boat has overall better performance without the tail.

I'm still hoping to get the dog out with me again this fall. He hasn't had a chance to drive the boat since he got his Canadian Pleasure Craft card.

If the foil isn't out of the water at WOT the motor needs to be raised, that's the fine tuning part of using one.

ondarvr, how far out of the water should the tail be at WOT?

 

[ondarvr]

Re: What does a whale tail do?

Every boat and motor combo will be different, but the higher the better, as long as you're still getting cooling water that is. At a certain point the prop will start to ventilate badly, that's when you start to lower it back down.

If you have a great deal of water splashing up and obscuring the view of the AV plate, then the motor is most likely mounted too low.