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I was thinking about adding a Hydrofoil to a Mercury 4 stroke 60 HP on a Dauntless 15.
In your opinin it may help and what is the best brand to buy for our loved Whalers?
Thanks Edo from Italy

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I use a stingray classic, however, I suggest you read a few articles on motor height/setup before that purchase. Many will say that it is an incorrect fix to the actual problem, I'm not totally sold on that but will now very soon.
I had tremendous bow rise on take-off so I installed the hydrofoil (which fixed the problem), but later I corrected my motor height (phenomenal performance difference by raising it one hole). I have not tried the motor without the hydrofoil yet but all I have read the hydrofoil should not be necessary now, I see this weekend.

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Try the Smart Tabs, I used them and they work great. I used the hydrafoil and was not very happy with the performance. with the smart tabs the boat jumps up on a plane very quick and i can trim the motor out to the sweet spot.

http://www.nauticusinc.com/smart_tabsSX.htm

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Foils are terrible and will only help partially at best. I used smart tabs to solve my issues but many here will tell you to adjust your engine height.

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Ah yes, I wondered how long the nah Sayers would take to chime in. I'm a confirmed convert that motor height is critical (even at the smallest measure, it just that such a tremendous difference), my issue is that if you have the motor height perfect then the hydrofoil should be somewhat out of the water therefore not causing any drag. This would mean that the only time it is involved is at take off and maybe turning. Again I'll let you know as I have removed mine to test the motor without it now that the motor is at the correct height.

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Ciao Edo,
I would suggest Smart Tabs (in Italy svama-nautica) and, if you want, a jacking plate.
See my Personal Page.

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X2 what Jimmy states......foils are nothing more than a band aide for a poor prop choice and improper motor height on the transom.

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Edo -

Tell us how the boat performs now. What is the top speed and engine rpm's at Wide open throttle (WOT)?

What is the prop size and brand?

What is the height of the motor on the transom. If you look at the top set of bolts holding the motor, how many empty holes are above the bolts:

Top
0 - bolt here is "all the way down"
0 - bolt here is "one hole up"
0 - bolt here is "2 holes up"
0 - bolt here is " 3 holes up"

Is the gear stowed so the weight is not all in the back?

Once we know this information we can recommend changes to improve performance.

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I have a heavy 18' Outrage (Guardian) and it was slow getting on plane. I had a old set of small size Doelfins in my shop. For a test I installed them on my Evinrude 150 to see if it would make any difference - it seemed to help. My motor is correctly mounted. It was an easy test since I had a set. Could be my imagination but running on plane it seems to handle a little better with the fins.

Good luck,

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Dear friends,
thank you very much for your nice answers.
I have just bought this 1998 Dauntless 15' without the engine that was stolen.
Now I have put on it a 2002 Mercury EFI 60 HP 4 stroke, the engine bracket has a total of 5 holes. Above the upper bolts there are 3 empty holes , and the anticavitation plate is about 1/2 inch down the hull.
To see it I have put the tilt so the anticavitation plate is parallel to the hull.
The prop is the one I found on the second hand engine and they told me it was on a bigger boat about 23 foot so it is a Mercury alluminium 10P.
I haven't been in water yet because I had to fix al the cables and wires that have been cut by the thief, so I don't know how it perform, but i would like to tune the boat /engine at the best before the launching with the Champagne!! ( Probably I'll use beer).
Ciao
Edo

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Edo -

The prop you have is not at all correct.

The anti cavitation plate should be 1" or 1 1/2 " above the hull.

We need to know if the Mercury 60 hp motor is a BigFoot model or not. The gearcase is different between the BigFoot and standard model and that makes a big difference for propeller.

If the motor is a Bigfoot, one recommendation is a 13-3/8" x 14" Mercury Vengeance.

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Phil,
I have checked again and the anticavitation plate is just at the same level than the hull.
How I can see if my motor is a BigFoot ?
Thanks
Edo

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I have discovered that my mercury isn' t a big foot

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On my 16 SL I have had both a Doel Fin and currently Smart Tabs. I do a lot of skiing with my boat so I wanted something to help keep the bow down at mid-range speeds. I settled on the Tabs as the Doel Fin had too much effect on steering for my liking.

John K.

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I think we need Tom to help on a proper propeller recommendation. I did not find a suggestion searching the threads.

Once Edo has the motor at the correct height and a good prop, he can test the performance and observe if he really needs a foil or tabs.

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So dear friends now it is the time to buy the new prop for my loved Dauntless 15 with his 60 Mercury 4 stroke no big foot.
What type or size do you suggest?

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What is the gear ratio and RPM range if the motor?

How fast does the boat go?

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Back to the Hydrofoil question. I have a 1973 13 sport that I recently repowered. My old 40hp Evinrude had a Doelfin hydrofoil. I replaced it with a 40hp Yamaha with a 15" prop that did not have the hydrofoil. I noticed he boat was taking (3) times as long as before to get on a plane and porposed at the slightest change in trim setting. I purchased a SE Sport hydrofoil and installed it on the Yamaha 40. The boat will now plane in a couple of seconds and will run within 2-3 mph of the top speed without the hydrofoil. I think the trim shape of the SE Sport cuts through the water smoother and quieter. I also had experienced a signficant gas mileage drop with the Yamaha, the hydrofoil has returned my fuel usage to the previous level. I am going to say the hydrofoil in my opinion is thumbs up.

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Get the BOBSMACHINE TRUE TRACK STABILIZER - It has a little more performance research behind it, provides planar, higher speed tracking & stability that the winged things don't, its made of aluminum, and it doesn't look like a "corrective measure". Cool is important, ya know,

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Tiger

Edo started this thread to discuss his Dauntless. While we want to help you, it would be more helpful to start a separate thread to discuss your 13' model.

All:

We want to work the basics first before getting to whether a foil will be appropriate. Keep in mind there are some models where a foil is very helpful (I.e. a 16SL)

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Phil,

I think the original question was addressing the brand of hydrofoil more specifically than the model of boat. My reply was based on my hydrofoil experience and my boat model was only included as a basis for comparison.

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For Tom the gear ratio of Mercury is 1:1.83 and the RPM is 5500 6000.

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A Dauntless 15 with a Mercury 60 should be good for what? 37-38 MPH?

With its 1.83:1 gear ratio and 6000 redline, you would make good use of a 11" or 12" pitch propeller. The gearcase on this motor is a class "C" size meaning it has a bullet of approximately 3-1/2" width so uses a propeller with a 3-1/2" diameter hub.

Mercury does not offer much. The 11-5/8" x 11" or 11" x 12" Vengeance is it for stainless steel three blades. There is also a 10-5/8" x 12" Trophy Sport four blade I have no experience with.

PPI offers under their Turbo and Stiletto brands two models that might work. 10-1/2" x 12" Turbo Hot Shot/Stiletto Triad or the 12" x 11" or 12" x 12" Turbo Pontoon 1/Stiletto Star.

Regardless of propeller is chosen, if your motor's A/V plate is even with the keel now, the motor should be raised one, if not two, more sets of bolt holes.