hydrofoil that attaches to sterndrive

[torcano]

Does anyone have any experience with using the hydrofoil that attaches to the cavitation plate of the sterndrive. The manufactures claim they improve fuel economy and get the boat to plane faster and stay on plane at lower speeds. Is this just hype or do they really work?

 

[DBreskin]

Re: hydrofoil that attaches to sterndrive

Most boaters dislike/avoid drive-mounted fins. I suggest (and use) Smart Tabs by Nauticus.

Rather than ask about a product, I suggest you post what problem you're trying to correct. Maybe the knowledge of the forums can help.

 

[Steve91T]

Re: hydrofoil that attaches to sterndrive

Does anyone have any experience with using the hydrofoil that attaches to the cavitation plate of the sterndrive. The manufactures claim they improve fuel economy and get the boat to plane faster and stay on plane at lower speeds. Is this just hype or do they really work?

Don't bother. Just get Smart Tabs. Cheap, easy to install, and automatic. They actually do everything they claim.

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

 

[Steve91T]

Re: hydrofoil that attaches to sterndrive

Most boaters dislike/avoid drive-mounted fins. I suggest (and use) Smart Tabs by Nauticus.

Rather than ask about a product, I suggest you post what problem you're trying to correct. Maybe the knowledge of the forums can help.

Dang it, beat me to it!

 

[shrew]

Re: hydrofoil that attaches to sterndrive

My problem is with the physics of what we're dealing with here. A boat planes on it's hull. Whether an outboard or an outdrive (I/O) the force exterted on the transom from the prop spinning is a horizontal, while the lift on the hull getting and staying on plane is vertical.

With a hydrofoil on the drive, whether it be an outboard or an I/O is now transferring vertical lift to the drive. This is placing stress on the mounting bracket of an outboard, or the transom collar of an IO. Neither of these were really designed to handle vertical force. Trim tabs, whether they are smart tabs, electric or hydraulic (These only dictate how the tab itself is actuated) are all mounted directly on the hull. The hull handles the force of the verticle lift, not the drive components.

Just my .02

 

[Tabman]

Re: hydrofoil that attaches to sterndrive

Does anyone have any experience with using the hydrofoil that attaches to the cavitation plate of the sterndrive. The manufactures claim they improve fuel economy and get the boat to plane faster and stay on plane at lower speeds. Is this just hype or do they really work?

If the boat you are talking about 2004 Chaparral 290 Signature with Twin 4.3L MPI Mercruisers I would think that you probably already have remotely controlled Trim Tabs already installed. I think they are Bennett and as I recall they are mounted on the "extensions" on the sides of the transom.

I do not recall what size they are, but if you can get me the measurements I would suggest looking into retrofitting larger ones. It's relatively inexpensive, usually easy and if we can fit larger ones, far more effective than adding hydrofoils.

Tom McGow
Bennett Marine

 

[Skiya]

Re: hydrofoil that attaches to sterndrive

For a 20' boat, smart tabs

 

[Thalasso]

Re: hydrofoil that attaches to sterndrive

For a 20' boat, smart tabs

If it is like Tabman say's it might be all the components are already there. Why remove everything to put something else on?Did you look at the sig? If this is the boat then, it is far larger then 20ft.(2004 Chaparral 290 Signature
Twin 4.3L MPI Mercruisers)

 

[Skiya]

Re: hydrofoil that attaches to sterndrive

Opps.....was looking at the wrong sig.

 

[QC]

Re: hydrofoil that attaches to sterndrive

Listen to Tabman

If either SmartTabs or Hydrofoils end up on that boat I will personally find it and remove them

 

[coastalrichard]

Re: hydrofoil that attaches to sterndrive

Couldn't agree more QC...and ole Tom is becoming a nice source of info

 

[NYBo]

Re: hydrofoil that attaches to sterndrive

My problem is with the physics of what we're dealing with here. A boat planes on it's hull. Whether an outboard or an outdrive (I/O) the force exterted on the transom from the prop spinning is a horizontal, while the lift on the hull getting and staying on plane is vertical.

With a hydrofoil on the drive, whether it be an outboard or an I/O is now transferring vertical lift to the drive. This is placing stress on the mounting bracket of an outboard, or the transom collar of an IO. Neither of these were really designed to handle vertical force. Trim tabs, whether they are smart tabs, electric or hydraulic (These only dictate how the tab itself is actuated) are all mounted directly on the hull. The hull handles the force of the verticle lift, not the drive components.

Just my .02

The weight of the outboard or the outdrive IS vertical force, so a hydrofoil should actually reduces vertical force on the transom collar/outboard mounting bracket (unless it exerts a lot more lift that the weight of said outboard/outdrive). Just sayin'.

 

[QC]

Re: hydrofoil that attaches to sterndrive

Just sayin'.

Stop sayin' . . . People might buy more Hydrofoils

 

[Steve91T]

Re: hydrofoil that attaches to sterndrive

OK, so let me ask the question. I've always heard how bad they are, but why? I personally think that the drive is experiences so many forces that it doesn't matter what you bolt onto it, it'll be fine. That's like saying, you can't add a blower to your car because your motor mounts aren't meant to handle ANY extra forces.

As a smart tabs owner, why is the hydro foil so bad? On paper, it seems like it would help.

 

[Oshkosh1]

Re: hydrofoil that attaches to sterndrive

If they work so well and had "advertised" benefits...the OEM drive manufacturers would have ALREADY added them.


Merc has MUCH, MUCH more time, money, and PhD power...,and if they could PROVE a noticable advantage in performance(with a myriad of different hull manufacturers) over the competition for the little added cost they would have designed their drives accordingly.

 

[QC]

Re: hydrofoil that attaches to sterndrive

As a smart tabs owner, why is the hydro foil so bad? On paper, it seems like it would help.

They work well on some very small OBs. Since you can adjust height of the OB then you can get the fin out of the way once on plane. With an I/O that can't happen. Also they introduce some potentially unsafe handling characteristics on some boats. The fact is, that the only way to know is to test it, as some boats react much better than others.

I also STRONGLY agree with Oshkosh, and to follow that with the fact that many, many boat manufacturers factory install trim tabs. Nobody installs Fins

 

[Scott Danforth]

Re: hydrofoil that attaches to sterndrive

fins should be outlawed. people put them on boats, get mad at them, then take them off leaving 4 holes in the outdrive. then they put on trim tabs

 

[nlain]

Re: hydrofoil that attaches to sterndrive

I will say I am happy with Smart Tabs, but your boat needs more, it is already equipped with Bennetts, work with Tom and use what he says. I have watched both Tom with Bennetts and John with Nauticus, (Smart Tabs) they are both top notch people and will not steer you in the wrong direction.

 

[metriccrescentwrench]

Re: hydrofoil that attaches to sterndrive

The weight of the outboard or the outdrive IS vertical force, so a hydrofoil should actually reduces vertical force on the transom collar/outboard mounting bracket (unless it exerts a lot more lift that the weight of said outboard/outdrive). Just sayin'.

FINALLY - someone who understands force vectors !!!! Yes, the vertical force exerted by hydrofoils is doing nothing more than offsetting a portion of the weight of the engine (in the case of an outboard) or outdrive.

As stated by others, on some boats they help get the boat on plane faster and help to keep it on plane at a somewhat lower speed. I've got one on my 15' fish-n-ski with a 90 HP outboard and I like it, the boat jumps on plane and there are no ill effects. I'm probably going to try a hydrofoil on my Checkmate to make driving it easier at tubing and wakeboard speeds (that hull is made to go fast, not lollygag around at 18 to 20 mph).

As others have stated, it might slow you down some with an I/O if the foil is underwater at planing speeds. Only way you'll know for sure is to try it and see.

 

[torcano]

Re: hydrofoil that attaches to sterndrive

I didn't expect so many comments but I wouldn't even consider putting them on my boat after reading all these comments. Thanks. My old boat was a Chaparral Signature 290. My current is a Searay 280 Sundancer. Both boats have hydaulic trim tabs and I used them to facilitate getting on plane and adjusting them accordingly once on plane for maximum performance. I was just was reading about the hydrofoils and the claims by the manufacturer seemed allurring since they are not that expensive. This forum is has always been a great source of information. Hydrofoils have just been removed from my list of must have gadgets.