Dolefins

[Rolf]

As previously mentioned in harley's new motor thread, I have installed dolefins on my 90 and will test them (along with new sportpilot plus!) Thurs-Sunday provided weather calms down (stormy rain here in SoCal.).
Does anyone have experience with these? I here great things about 'em, will find out soon myself.
Rolf



(Search terms hydrofoil, doelfin, dolefin, dole, doel, stingray, sting)

[Timm Miller]

I know the work great on I/O setups........most people on here that have tried it end up taking them off.

[Moe]

There's a Whaler series named "Dauntless" which is very stern-heavy, in part, due to a large under floor fuel tank right in front of the transom. These boats are often prone to porposing if the owner tries to trim out past full down. Quite a few of their owners report improvement with the Doel-Fin and StingRay, and several have had even better improvement with a no-drill solution called the Turbo Lift from Grand Isle Marine. They don't have a website, but their phone is 321-452-8126. One owner has posted several pictures of his online. Whaler Corporate recommends this one.

One thing that's very important when using one is to ensure the outboard is installed at or slightly above the bottom of the transom, so that the fin is running on the surface of the water once up on plane. If it's submerged it creates a lot more drag, and can even contribute to porpoising if the motor is trimmed out too far.

I'm not sure how well one of these hydrofoils would work with a Mac that stays in the hole, with the stern never stepping up on the surface. It might allow the motor to be trimmed out a bit, and reduce the load on it that way, but the increased load from the fin dragging in the water will probably cancel that out. I wouldn't drill holes my anti-ventilation plate to find out.

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Moe

[on edit] Fixed broken link to Turbo-Lift pictures

[Mark Prouty]

What about this puppy?


Cal-Neva Marine

[Dimitri-2000X-Tampa]

If someone wants to make an offer on my fins, I'm getting ready to sell them on Ebay. Not sure what brand they are, but I can find out. Email me if you are interested.

And btw Moe, I find it a bit amusing (concerning) that you are so adamant that a Mac "stays in the hole" when you have never even taken yours out in the water. Qualified opinions come from experience and IMHO, you are misleading potential Mac buyers by continuing to state unqualified innacuracies about this boat's actual performance based on your experience with other boats.

[Moe]

No, Dimitri, I've never taken mine out. I do however, learn from the experience of others, and in doing so, must determine who is credible. When I first joined here, I thought you were, but that has certainly proven not to be the case, at least as far as I'm concerned.
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Moe

[Duane Dunn, Allegro]

I to have a set of lightly used fins. They don't help with a 50 hp, they just add more drag. But with a 90 hp that can get the boat up on a (close your eyes Dimitri) full and level plane they might be useful.

[Dimitri-2000X-Tampa]

No, Dimitri, I've never taken mine out. I do however, learn from the experience of others, and in doing so, must determine who is credible. When I first joined here, I thought you were, but that has certainly proven not to be the case, at least as far as I'm concerned.
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Moe

Yea well, if you are trying to drive me off this board Moe, you may soon succeed because I am spending way too much time arguing with you any more...I suppose I could just let it go, yet I can not just stand by and let other people believe everything you say as gospel...when you are not even qualified to make such statements.

And as for your personal insults, I certainly do not need to spend this time sharing my experiences with know-it-alls. I could tell you about my real experience with fins on a Mac, but you would likely just shoot it down with a bunch of your high falluting theoretical crap based on other boats, other people's opinions, etc. Why should I even bother?

It is laughable for you to think you are more credible than me here. I have 1.5 years of experience on this boat (used almost every week) and you have none. I have owned many other boats before this boat yet I am open minded enough to understand that perhaps a Mac doesn't perform the exact same way as my other boats did. Contrary to you, for the first 6 months or so that I was here...(4 months before I bought and 2 months after I first used my Mac), I never posted hardly anything here...I just listened and absorbed. I certainly would never have had the audacity to make unqualified statements like you continue to make. How the hull do you even know if a Mac ever porpoises??? If you pay attention to uncredible people like me who have experience, you might learn that the Mac has never porpoised on me...with fins or without..and therefore, once again, you are misleading people, while trying to pass yourself off as an expert on everything.

[Dimitri-2000X-Tampa]

I to have a set of lightly used fins. They don't help with a 50 hp, they just add more drag. But with a 90 hp that can get the boat up on a (close your eyes Dimitri) full and level plane they might be useful.

Get your 90HP, and then post a picture of how level your boat really is. Show me the pics!!!

[Moe]

Yea well, if you are trying to drive me off this board Moe,

Dimitri, you were the one who came into this thread and took a shot at me. You were the one who got personal with the "supremacist" and "pompous" comments in the planing thread. If you can't stand my responses, don't do that.

And if you want to debate an issue, read what I write. Your responses are to things you say I said, but didn't. See below.

It is laughable for you to think you are more credible than me here.

I didn't say that... but I DID imply that others here are.

How the hull do you even know if a Mac ever porpoises??? If you pay attention to uncredible people like me who have experience, you might learn that the Mac has never porpoised on me...with fins or without..and therefore, once again, you are misleading people, while trying to pass yourself off as an expert on everything.

I never said Macs in particular porpoise. I said stern-heavy boats (in general) can porpoise once up on plane. If you're not getting up on plane, then it stands to reason it wouldn't porpoise on you.

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Moe

[Rolf]

Hey, all I wanted to know was some feedback on a Mac with dolefins! Guess I'll have to find out for myself. Dimitri, Moe, you two are good guys and I like reading both of your comments and you are both obviously smart. But enough of the Girlie-Man crap! If I want to hear arguments I'll talk to my wife! We are all here because we love the Macs -- a little courteous disagreement is fine, but more of this and I will e-mail a bitch-slap to both of you(okay, maybe not -- hot-head Italians and Harley mechanics are not to be taken lightly). I hereby call a truce between you two, and if you don't like what each other types DON'T RESPOND. Both of you ar highly respected, but that respect is gone if this continues. By the way, I will give a 90 horse dolefin update soon. If I hit 30 knots -- they stay.
Rolf

[trapeze]

On the very bottom of this page http://www.macgregor26.com/safety.htm on the Mac site, states the following about the 26X:

"Do not install a lifting hydrofoil on the cavitation plate of the outboard motor. These are airfoil shaped wings, offered in various sizes and shapes. Their purpose is to provide lift at the stern of the boat. This raises the stern and forces the bow down, allowing the boat to get up on a plane more quickly. If they do keep the boat level when coming up on a plane, the ballast tank may not drain completely when the boat is underway. You may think you have an empty tank, but you may not.

These hydrofoils create another problem when the boat turns or leans sideways while underway. The lift that they provide goes straight up the centerline of the outboard motor, adding a strong force to promote further leaning or capsize.

These devices can exert a large amount of force; enough to snap off the cavitation plate that is cast as part of the drive shaft housing. Avoid them."

[Rolf]

Thanks for that warning. I now remember reading it a couple years back--totally slipped my mind. Don't think I'll take any risks... off they go(its been too stormy here for boating, unfortunately).
Rolf

[Catigale]

This isnt in the manual under safety, but if you are out in 20 mph winds, and you discover the genoa is furled backwards, dont put your finger in the ring on the sail and unfurl it......

[Robert]

I ran with the http://www.piranhapropellers.com/hydrofoil.htm version of the cavitation plate foil. I chose this one for the material it is made of that will hold its shape and the great experiences I had with them testing piranhapropellers. They know thier stuff.
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The effect with my Suzuki DF-50 was that I could put the bow down and that let me see better where I was going. However, I did not find a speed advantage, except maybe with a lot of fine tuning of the motor tilt based on speed and water conditions there could be a small gain in top speed.
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Turning at wide open throttle... I had to test this for my self. Yes, it does feel easier to tip, but it did not feel dangerous to me, just take the turns a little slower.
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The PiranhaPropellers foils give 500 lbs. lift at 45 mph. At the Mac26 50hp top speed of approaching 20 mph, the foil would provide less than 1/4 that much lift, assuming the force is roughly proportional to speed squared.
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Would I get the foils again? With 50 hp yes I would, because I like to be able to see where I am going, to avoid running over stuff. With >90 hp, I might not, because I think the higher speed would get the bow down already, but I might test out foils anyway because I like the testing. With the larger motor at a slow cruise the foils would keep the bow down, high speed turns might get a little dangerous, with a smart captain at the helm the danger is minimized.