Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  Which hydrofoil is best?

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Which hydrofoil is best?
Wet Foot posted 09-17-2003 07:55 PM ET (US)   Profile for Wet Foot   Send Email to Wet Foot  
Hi Guys,

I want to put a hydrofoil on my 125HP Mercury. I have a 2001 18 Dauntless that takes too long to plane. It wont plane at all with 2 people on stern seat; need to move one to console seat. There are many discussions in the archive that I have reviewed, but no reasons for choosing one hydrofoil brand over another. I see Doel-Fin mentioned most. Does anyone have a good reason for choosing one instead of another? Are there other brands beside Doel-Fin and Sting Ray? Any reason for not wanting to drill holes in cavitation plate? Any downside to these gadgets?

JBCornwell posted 09-17-2003 08:36 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Howdy, Wet Foot.

I have had best performance with a SE Sport 300, though I have not tried every option, I have tried the Doel Fin and StingRay.

I think that the Cobra EDGE is a good looking product but haven't tried that one. Just cheap, I guess.

Red sky at night. . .

JohnJ80 posted 09-17-2003 08:37 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
My recommendation is for a Hydro Lift from Grand Island Marine. You don't need to drill the AV plate, it clamps on. It is made from Stainless Steel and it is specific to your motor.

I have had a Sting Ray before and I think the Hydro Lift performs better.

I would think your Dauntless 18 would plane with a 125HP, although it is underpowered. You will probably need to look at the vertical position of your motor on the transom. Can you tell us what hole position the motor is mounted on? If it is too low, the drag that is induced is dramatic and this could be a problem. Typically, the AV plate needs to be at least 1" above the bottom of the boat.


Rick Dewees posted 09-17-2003 09:15 PM ET (US)     Profile for Rick Dewees  Send Email to Rick Dewees     
I recently came across this one made in Corpus Christi, Tx called a Shaw Wing. Not cheap - $200. Has anyone any experience with it?


Wet Foot posted 09-18-2003 10:12 AM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Thanks for the replies! JB, who makes the SE Sport 300? John, my motor is mounted on the center hole, there are five holes. I have the 25 inch shaft. Not sure how to measure bottom of boat to AV plate...put a level straight edge on back most edge, or put level against bottom touching boat for a foot or two, and extending level to plate. My boat has the notched bottom as well.
4whaler posted 09-18-2003 03:33 PM ET (US)     Profile for 4whaler  Send Email to 4whaler     
I have the Turbo Lift (not Hydro) from Grand Island Marine it is stainless steel and bolts on with out drilling your cavitation plate. Best Ive seen. See Pics on my web site.

JohnJ80 posted 09-18-2003 05:05 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
oops, i have the turbo lift too. sorry.


Wet Foot posted 09-18-2003 05:23 PM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Thanks 4Whaler! Great pictures! I spoke to the guy at Grand Island Marine. He tells me the device does not push on AV plate but pushes up on lower unit housing. From the pictures, it looks like it lifts up on plate. Is it grabbing somewhere else that I can't see? He claimed the competitive brands put too much stress on plate...his looks like it lifts the same way.
Wet Foot posted 09-18-2003 05:43 PM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Do you think I should raise my motor up as high as it will go (2 more holes) if I buy the Turbo Lift, as the manufacturer suggests? I'm trying to avoid too much trial and error since my dealer will charge me $125-$150 each time they raise motor. How do I know when the height is optimized? They also tell me my WOT rpm's will increase significantly. Mercury says I should be 5000-5250rpm. Grand Island says 6000rpm is fine as long as I don't do it for too dealer says change the prop so don't exceed 5250rpm. What do you think? Does anyone let you exchange props when you do these experiments? I would think you might need a different prop each time you raise motor.
BillB posted 09-18-2003 06:32 PM ET (US)     Profile for BillB  Send Email to BillB     

Thanks for the link...I like the looks of the "Shaw Wing". Less bulk than the other foils I've seen...Doesn't look like a big 'ol ray ate your lower unit. I think it's worth investigating.


4whaler posted 09-18-2003 06:38 PM ET (US)     Profile for 4whaler  Send Email to 4whaler     
I think that since it pushes up all across the bottom of the AV plate and straddles the steering offset fin, and is not just attached at the AV tips/edges like the drill thru type do I guess you can say it lifts the lower unit not just the AV. See this picture.

Deak Link

Its one fine piece of kit as the Brits say. All stainless and heavy duty enough to use to get into the boat with.

I jacked up my motor to top hole myself and probably could go up more if I had the holes. (pully and chain over good tree limb with under support by jack just incase) My RPM didn't pickup all that much I still am not at max of 6000 WOT when light and by my self. I do breakout in very hard high speed turns to the starboard though. I cupped one of my props and it slowed down the RPMs a little more as the effect was like going up one more in pitch from what I understand, making it the speed prop. Had two (11.5x13's)

JohnJ80 posted 09-18-2003 09:13 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
Easy stuff first: Are you trimming the motor all the way in before you try to get out of the hole? If the motor is trimmed out, you can really make it tough trying to get on a plane.

Use the level against the bottom of the boat for a foot or two to see how low the AV plate is with respect to the boat.

Basically, though you should put some time aside to do a the science project because most of this is experimentation. You want to have the motor as high as you can get it without getting the prop to ventilate (blowout) and still have cooling water going to the motor (cooling stream out of the pee hole). The factors that will effect this are position of load (fore and aft), sea state etc...

Measuring will give you an idea but the best way is still by experimenting.

Minimum HP for your boat is (per whaler website) 115HP. You are not far from that lower limit. If your motor is in need of a tune up or has another problem you might not have sufficient horsepower to make her go up and out of the hole very well. More HP always helps.

I think, after looking at this spec, that getting the motor as high as you can will make a big difference. The amount of drag a 3/4" high by width of your lower unit produced is substantial at planing speeds.

The other thing you should probably look at is prop selection. Getting a high performance cupped and raked stainless steel prop will also help your hole shot big time. You can also go from a 3 blade to a 4 blade, but that will be at the expense of top end.

Does the boat go nose up dramatically when you put the hammer down? If so, a fin will help this dramatically. Between the fin and the prop, For fins, I prefer the Hydro Lift because is is heavy duty, stiff and doesn't need the AV plate drilled. For props, I like Stilletto - they tend to be cheaper, they work great and their tech support guys seem to really know their stuff.

getting the height right you should be able to really optimize what you have. Do the fin next, then the prop. Failing all that, trim tabs will also help the hole shot.

Moving the motor up a hole is not a big deal - in fact it is pretty easy. all you need is a hydraulic jack, a piece of 2x8 to put the under the motor skeg, a phillips screwdriver and silicon sealant if your bolts are blind in the little compartment in your transom, your trailer and two 3/4" wrenches or sockets.

Here is how you move it:
1. Put the trailer tongue flat on the ground. Chock the wheels fore and aft both sides.
2. Put a piece of wood under the motor skeg. Motor should be vertical.
3. put jack under trailer tongue and put a little tension on it (motor skeg resting on the wood taking the tension).
4. Unloosen the bolts that go through the holes and remove them. Leave the sliding bolts tight.
5. loosen but don't remove the sliding bolts. Have someone steady the motor to keep it vertical.
6. Jack up the trailer toungue. This will try to force the skeg down, but since the motor is loose, it will start sliding up.
7. Keep jacking it up until you get to the hole you want. Then reinsert bolts and tighten.
8. You might have to kind of jiggle the motor back and forth (side to side) to help it slide up. It might try to bind against the transom a bit.

Whole thing takes about 30 minutes the first time you try it, 15 minutes the next time - you can do it right at the boat launch ramp parking lot. No big deal.

Set aside an afternoon at the ramp and go experiment. I would move your motor up until the AV plate is between 1" to 1-3/4" above the bottom of the boat - experience seems to say this is the best. You will have to try it to see. You just need to make sure you have cooling water and that the prop doesn't blow out. All of this depends on the way you use your boat, load it and the sea state of the waters you boat on.

One hole movement can make a huge difference. There really is no way to predict what will be optimal, you just need to try it. I am thinking that if you can get the motor up, you will have less drag and this will help you plane.


JohnJ80 posted 09-18-2003 09:18 PM ET (US)     Profile for JohnJ80  Send Email to JohnJ80     
Jeez, i keep having senior moments with this fin. Its a turbo lift not a hydro lift! Anyhow you get it from Grand Island Marine and it is a nice product.


Wet Foot posted 09-19-2003 12:48 PM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Thanks John J and 4whaler! John, I am trimming in all the way to get out of hole and it does nose up alot. My 2001 Dauntless has a minimum 90HP...boat is 200lbs lighter than new one and has notch in bottom at transom. Not sure how to use level with the bottom notch. I could go forward beyond notch to catch the real bottom, but bottom is not level, and by the time I extend to AV plate, I might be getting a false reading. As far as experiment goes, will optimum height without fin remain optimum, after fin is added, or do I need to install fin with each height change? Could it be that raised height and different prop will eliminate need for fin? Is ventilation obvious or do you need a trained ear (or just look gages)? Should I care about Mercury's 5000-5250rpm for correct prop? Thanks for spending time to help me!
arnereil posted 09-19-2003 12:56 PM ET (US)     Profile for arnereil  Send Email to arnereil     
Have done numerous searches on 'turbo lift' spelled every way in can think of and nothing comes up... is there anything else that will limit search so i don't wind up in game areas?
lakeman posted 09-19-2003 02:52 PM ET (US)     Profile for lakeman  Send Email to lakeman     
I have the SE300, dealer recomended, on my 18 Dauntless/135 opti. I do not have a oppinion on how good it is, but I think it could be better, I have had a stingray on another boat and like it. I might try Bob's Machince Shop product if, after adjustments, the performace does not change. Or I might spring for the TABs, which I think may be the ultimate answer.
Wet Foot posted 09-19-2003 03:02 PM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Lakeman, who makes the SE 300? What is Bob's Machine Shop?
Arnereil, There is no Turbo Lift website. I think it's a small shop.
4whaler posted 09-19-2003 05:22 PM ET (US)     Profile for 4whaler  Send Email to 4whaler     
You are correct there is no Turbo Lift web site. The Turbo Lifts look custom made in a small machine shop and sold thru Grand Isl Marine in Florida. I had to wait 4 weeks for them to get mine in to ship for my 60 hp Yami 4 stroke. There are several strings on it here in Continuous Wave though. The fact that Boston Whaler supposedly was recommending it for some of their commercial boat customers (USCG) made me intrested enough to check it out and eventually buy it. I haven't seen anything comparable or as well made. Not cheap though. $165 but not plastic either, all stainless plate.
It helped eliminate my problems. I have misplaced the Grand Island Marine telephone number, someone else have it?
Wet Foot posted 09-19-2003 05:49 PM ET (US)     Profile for Wet Foot  Send Email to Wet Foot     
Their phone number is 321.452.8126. The Shaw Wing mentioned above seems to attach in a similar way.
Donnie Cockerham posted 12-15-2007 09:46 PM ET (US)     Profile for Donnie Cockerham  Send Email to Donnie Cockerham     
I have an 18' alum. boat with a 75 Merc. runs great with the se sport 300. It broke off and I'm thinking of replacing it with a Stingray xplll. Has anyone had any experance with this hydrofoil??
Jefecinco posted 12-16-2007 11:05 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
First, raise the engine one hole. Next, take a ride and play around with your trim while getting on plane. With my set up (Daunntless 16 & 115 Evinrude FICHT) I get the best result by starting out trimmed fully in and begine trimming out as soon as I go to full throttle. Ultimately I am trimmed out about 50% while cruising according to the trim gage. I doubt you'll ever want to trim out more than 50%. You are going to full throttle immediately when getting out of the hole, right?

If hole shot remains unacceptable you may want to go up another hole on the transom. Then get back in the water and play around some more. Next, if you remain unsatisfied try a different propeller. Tom Clark recommended a propeller change for my boat and the results were outstanding. Tom or your local Mecury dealer may be willing to work with you on that.

After trying different operating approches, transom heights, and propellers a hydrofoil may be in order. Mine is a Stingray and it was very helpful before changing my propeller. I intend to remove it when I get the urge as I am not certain it is needed now that the propeller is so well dialed in on my boat.


Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.