Remove the Whale Tail!

[DJ]

Re: Remove the Whale Tail!

I've never been a fan of them. A "good" set up should negate any benefits derived from them.

My current rig is running with four open holes from a previous "tale". No issues whatsoever. I'll fill them if I EVER have nothing to do.

 

[JimS123]

Re: Remove the Whale Tail!

I'm not sure I agree with that statement at all.

A boat comes on plane as a result of hydraulic lift on the hull. These hydrofoils are creating additional lift on the drive and transom assembly. No, you're not placing the entire boat on the drive, however you are adding a significant amount of weight and force on the drive and transom assembly than was intended by design. Allow the hull to lift teh boat. Even trim tabs will give additional lift and transfer it across the transom, not the drive and assembly.

At speed in calm seas there is a heck of a lot of force put on the outdrive just by the fact that its plowing through the water. In choppy conditions, where the boat goes from 100% in the water to OUT of the water and back again, the force on the drive and drive-to-hull connection must be astronomical. Nope, I don't buy the excess stress theory.

 

[JimS123]

Re: Remove the Whale Tail!

I disagree. You could see on mine that the fin on my old boat had UPWARD pressure applied to it, not down and it snapped off an entire corner of the outdrive's fin. It was'nt from hitting something, just undo stress. IF and I mean IF they worked as well as everyone thinks, the OEM would make a simple casting change to the out drive casing and add the tail. NONE that I'm aware of have.

Honestly, IMHO they're snake oil.

Look at Volvo outdrives. They have gotten wider in recent years. Wonder why?

IF they worked as bad as some say, and IF they caused everyone's outdrive to snap off, they would have gone out of business long ago.

IF the "added stress" was true, eventually all would fail. So, how long does it take? One of mine has logged about 1300 running hours over 27 years and it shows no stress cracks.

If they were snake oil, consumers would have weeded them out of the market. I will agree that they may not work in ALL situations, but so far I've only found one case that it didn't work. Four of the other boats in the family have them on and we've been delighted with the perofrmance improvement.

 

[LiFeStArTs@FoRtY]

Re: Remove the Whale Tail!

At speed in calm seas there is a heck of a lot of force put on the outdrive just by the fact that its plowing through the water. In choppy conditions, where the boat goes from 100% in the water to OUT of the water and back again, the force on the drive and drive-to-hull connection must be astronomical. Nope, I don't buy the excess stress theory.

You're looking at it the wrong way... The little flange that the foil bolts on to would have no stress on it using your calm sea analogy because the the fin is cutting through the water. On your second analogy, the foil would be trying to shear off the fin, as if you took a large cresent wrench on the end of it and lifted up. Now maybe in the your second analogy, your 4000lb. 19ft. boat might not shear it off, but my 7000lb cruiser DID.

Like I said, take a long cresent wrench to the back of the fin on your out drive nice and close to the 1/2" holes that are drilled through for the foil and lift up. I'd bet a 5th grader could snap it easily.

 

[45Auto]

Re: Remove the Whale Tail!

Some boats perform better with hydrofoils, some perform worse, some it makes no difference. No way to tell without trying it.

They will put additional stress into your anti-ventilation plate. No way around that. If the stress level exceeds the limits of the cast aluminum, it will break.

I can easily see how you could break a corner of the anti-ventilation plate if you had 3 loose bolts on your hydrofoil and put all the load into the one remaining tight bolt on a corner of the ventilation plate. You can probably break it yourself by taking out 3 bolts and lifting on the corner of the hydrofoil farthest away from the bolt so you apply the greatest moment to it, much less the weight of the boat crashing down off a wave onto it.

On the other hand, a properly installed hydrofoil with all bolts tight will distribute all load into all 4 bolts, with a much shorter moment arm limiting the load on each bolt. In that case, you would most likely break or bend the plastic hydrofoil before you could come anywhere near the limit stress of the aluminum casting.

 

[southkogs]

Re: Remove the Whale Tail!

Whoa! Y'all are serious about this! I was just wondering if I should fill the holes up or not

I haven't fixed the trim system on the stringer drive yet, so the drive isn't trimmed as well as it should be. Not too big a problem, because we don't run on plane that much right now. I'm replacing the drive with a spare had a foil on it (not a Whale Tail brand), but it was broken and I'd like to see how the boat runs without it anyhow. Once I fix the trim (next project), I can see how it trims out without a foil. I've got a foil on the original lower if I feel like want one back on.

I've run outboards since I was a teenager and never had a foil before, so I kinda' lean against needing one - but we'll see which side of the debate I wind up landing on.

 

[Silver Eagle]

Re: Remove the Whale Tail!

I tired one of them and it made my boat harded to turn with and it seems to hold the trim back some.So i gave it to a friend to try out. he didn't like it either.as for the holes I used a couple of pop rivits.

 

[JimS123]

Re: Remove the Whale Tail!

Whoa! Y'all are serious about this! I was just wondering if I should fill the holes up or not

I haven't fixed the trim system on the stringer drive yet, so the drive isn't trimmed as well as it should be. Not too big a problem, because we don't run on plane that much right now. I'm replacing the drive with a spare had a foil on it (not a Whale Tail brand), but it was broken and I'd like to see how the boat runs without it anyhow. Once I fix the trim (next project), I can see how it trims out without a foil. I've got a foil on the original lower if I feel like want one back on.

I've run outboards since I was a teenager and never had a foil before, so I kinda' lean against needing one - but we'll see which side of the debate I wind up landing on.

Yup, fill em up if they bother you, or leave them alone. No matter either way. I had a tinny that was overpowered and gave squirrely results, so I took it off and just put the original bolts back in the holes. When I upgraded boats and found I needed the DoelFin again I reinstalled it and problem solved.

As you've seen its a hot topic. If you've got loose bolts or your motor isn't adjusted properly, you'll hate it. Use a torque wrench and set it up correctly and you'll swear by it. By the very nature of some of my personal boats (the fact that they are stern heavy by my design), I can't live without it.

I rarely endorse products, but when I find something that solves a personal problem, costs only a few bucks and lasts for years and years, then only to find other people trashing it, I just can't help but comment.

If I knew Doelfin was going out of business, I'd buy a half dozen so I'd have a lifetime supply.

 

[LiFeStArTs@FoRtY]

Re: Remove the Whale Tail!

JimS123, I think we got off on the wrong foot. You've made some valid points based on YOUR experience and I respect that. However, I've given points based on my own experience and that of the welder the our marina uses that did my repair. He told me that he does that very repair on a frequent basis. I've been accused of improper installation of lack of maintenance by .letting the through bolts come loose. I think we can agree to diagree on this and present our points of view and let the reader decide if it's for them. Just don't acuse me of blindly "trashing" a product as one those I know a friend of a friend who's brother's cousin that said they suck kind of guys. That's not the case here.

 

[JimS123]

Re: Remove the Whale Tail!

JimS123, I think we got off on the wrong foot. You've made some valid points based on YOUR experience and I respect that. However, I've given points based on my own experience and that of the welder the our marina uses that did my repair. He told me that he does that very repair on a frequent basis. I've been accused of improper installation of lack of maintenance by .letting the through bolts come loose. I think we can agree to diagree on this and present our points of view and let the reader decide if it's for them. Just don't acuse me of blindly "trashing" a product as one those I know a friend of a friend who's brother's cousin that said they suck kind of guys. That's not the case here.

When I made my comment about trashing them, I wasn't even thinking of you. The trasher to lover ratio around here is about 100:1.....LOL. So, you're in good company.

Funny observation from last Sunday while anchored in shallow water out at the beach....Probably about 20 boats in the same area as us. All had their outdrives raised. I didn't actually make a count, but I'd say that the majority had fins. All were brands that stuck out the back. My DoelFin is mounted on the side. Just wonder if that makes any difference re. durability.