Hydrofoil on i/o

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JGJR

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06 Sea Ray 185 Sport, 4.3l tks, Alpha one gen 2. The boat has a good sized hydrofoil attached to the outdrive, not sure of the brand, was there when I bought the boat. I am thinking of installing smart tabs, advertised to address some performance problems i think I have, namely slow to plane, bow rise, bow wander at slow speeds. A lot of these problems could be due to lack of experience, I know. Improper trimming and such.
My question is, if I do install the smart tabs, should I remove the hydrofoil or use both? Are they intended to address different issues? Pros and cons, try both and see what I prefer, any problems I should expect either way, etc. Also, this may not be the proper forum for the question, also inexperienced, so please bear with me.
 

Bt Doctur

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an 18 footer with 200 hp available should not need a whale tail or smart tabs
I run a sr 220 with that motor and it performs just fine
Slow to plane , drive not down all the way, too large of a prop
bow rise, drive not down all the way
wandering , some boats just do that, trim tab not adjusted correctly, puls to 1 side
 

Rick Stephens

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I've never run a hydrofoil on a drive, so can't opine there. However, I do run Smart Tabs on a 17 footer with a 4.3L and really like them. Boat will pop up on plane in a couple seconds. Biggest change was how it took the bang out of crossing wakes.Like having shock absorbers back there.

I don't really have good before and after testimony though as I installed them when the boat had a 3.0L installed and never ran the boat with the 4.3 V6 without em. My educated guess is they are less impact now that I have the bigger motor. I do disengage them when pulling wakeboarders so I push a bigger wake out. Still hard to keep the boat off plane, even with them disconnected from their gas springs. Horse power is a bigger factor.

Would I install them again? You bet.

You might weigh your boat and see if it in the range it is supposed to be. And post what prop you have and what RPM and speeds you get at wide open throttle.
 

JGJR

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Thanks for the responses. WOT RPM 4500, 46 MPH on GPS. 14.25" 21p 3 blade aluminum Turning Point. The boat came with a 3 blade stainless 23p (Mirage, I think?) that has some chips and a small crack in one blade, so I replaced it and haven't gotten around to having it fixed yet. I have a wakeboard tower that also came installed on the boat, so I'm guessing the extra drag will skew my numbers a bit.
But the improved wake crossing sounds promising.
 

Scott Danforth

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all v-hulls with a single prop wander at low speed. if you want to get away from that, get dual prop outdrive or run twins

the fin on the back is something I always am opposed to. it adds drag, drag adds suck, suck simply adds misery to the boating experience

the prop you are running is for top end only. your hole-shot will suffer. in fact you are on the lower end of the WOT RPM

how do you do your hole-shot? be specific. (you should be trimming in, mashing the throttle and as the boat is climbing the hole, start raising your trim while backing off the throttle)
 

JGJR

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The hole-shot procedure you describe is what I try to do, although I'm probably not coordinated enough yet to time it correctly. To be honest I'm still pretty nervous driving my boat, although it's getting easier. I've also been dealing with an intermittent, random engine alarm ( hopefully I've got that fixed now) that seemed to always chirp with changes in momentum, which was distracting to say the least. I'd say I probably start trimming up too late, after the boat is already up the hill and starting to plane. Bow rise is pretty significant, and the reduced visibility is distracting also.
I've tried to find what is the recommended prop for my set up, but haven't been able to nail it down. I was talked out of a 19p when I bought the current one, might try that.
What is the purpose of the hydrofoil? Keeping water on top of the prop? Does it help at all with planing ability or stability?
 

Scott Danforth

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you may be trimming up too soon if you have that much bow rise.

also, if you have a cooler in the back, move it forward.

as far as the purpose of the hydrofoil, my guess to lighten your wallet.
 

H20Rat

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an 18 footer with 200 hp available should not need a whale tail or smart tabs
I run a sr 220 with that motor and it performs just fine

Actually that type of boat benefits quite a bit! My previous boat was a 18' with a 4.3l, current is a 19' with a 4.3l. Shorter hulls with a relatively heavy drivetrain at the back makes for a use case for smart tabs. Longer boats have more weight up front.

Not for holeshot, but for reducing planing speed to something reasonable. In my case both of those boats weren't happy below 22-24 mph, and after smarttabs could maintain plane down to around 16-17mph.

In any case, OP, as mentioned above, I've had two boats very similar to yours. My current one actually came with a whale tail on it from the previous owner. Ran it a couple times with the whale tail, didn't like it, and smarttabs were installed. Big improvement! Like someone else mentioned, they actually do work like shock absorbers and soften the ride, in addition to the planing benefits.
 

QBhoy

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Totally and utterly against such a thing...but it is good for staying on the plane at lower speed if you are into wake boarding. Only slight advantage I’ve seen.

Your other questions have have been answered I’d think.
All stern drive planing hulls wander at slow speed with little exception.
Your bow rise thing is a little more confusing. Especially with one of these horrible things on it.
Hydro dynamically speaking these are a disaster. Some even claim improved speed. This is literally impossible.
As for tabs. I get them. But also not for me. A boat like this shouldn’t need them...but I do understand that in some cases and adjusted correctly so to be as less intrusive as they possibly can be at higher speed..then each to their own. Not for me though. As an engineer and in a previous life, a merchant navy marine engineer..they go against the grain personally, haha.
 

HT32BSX115

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all v-hulls with a single prop wander at low speed. if you want to get away from that, get dual prop outdrive
I didn't notice any difference in my wandering Four Winns Liberator 211 when I yanked out the OMG 460 King Kobrah and replaced it with the Merc 454 Bravo III.

It still "wanders" at idle and slightly above idle.

It's of a more a V-bottom phenomena being pushed than what it's pushed with
 

Scott Danforth

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Most of the wander is "prop walk" best to just let it wander back and forth over the 20-30 foot wide path

if you try to correct, it just gets worse.
 

HT32BSX115

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Most of the wander is "prop walk" best to just let it wander back and forth over the 20-30 foot wide path

if you try to correct, it just gets worse.

Yup! If you leave it alone, it does slowly turn the other way.

The oscillations get less and less as you speed up slightly as the keel becomes more effective.
 

Scott Danforth

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Its also easier to drink your beer if you let it wander....
 

H20Rat

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I have an 18 1/2 ft with an even heaver V8, I think it does well with no Tabs or Whale Tail/Doelfin

https://www.youtube.com/watch?v=5WBf2D0103Y

'ya sort of missed my entire point. Had nothing to do with top speed or acceleration. What is your minimum GPS speed to remain cleanly on plane? If you have a 3 blade prop, I bet it is in the mid 20's. A 4 or 5 blade might get you to low 20's. Smarttabs will get you to high teens on a 3 blade.

(might not seem like an important point of performance, but I pull kids wakeboarding and tubing. mid 20's is too fast for either)
 
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jimmbo

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My lowest clean planing speed is 21-22 mph. No Tabs or funny Fins. My current prop is an Enertia, a 3 blade
 
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Chris51280

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Thanks for the responses. WOT RPM 4500, 46 MPH on GPS. 14.25" 21p 3 blade aluminum Turning Point. The boat came with a 3 blade stainless 23p (Mirage, I think?) that has some chips and a small crack in one blade, so I replaced it and haven't gotten around to having it fixed yet. I have a wakeboard tower that also came installed on the boat, so I'm guessing the extra drag will skew my numbers a bit.
But the improved wake crossing sounds promising.

How fast did you go with the 23p? I have a ss mirage that came with the boat that I never used. Currently I have a AL 14x19 and get around 42mph at 4500.
 

Chris51280

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Thanks for the responses. WOT RPM 4500, 46 MPH on GPS. 14.25" 21p 3 blade aluminum Turning Point. The boat came with a 3 blade stainless 23p (Mirage, I think?) that has some chips and a small crack in one blade, so I replaced it and haven't gotten around to having it fixed yet. I have a wakeboard tower that also came installed on the boat, so I'm guessing the extra drag will skew my numbers a bit.
But the improved wake crossing sounds promising.

How fast did you go with the 23p? I have a ss mirage that came with the boat that I never used. Currently I have a 4 blade AL 14x19 and get around 42mph at 4500.

I have a whale tail on it too that came with the boat. Still have to try out without it. I bought smart tabs too but I'm not sure they will work on mine since the transom has a 30degree angle
 
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