# Hydrofoil vs. ventilation plate.



## SClay115 (May 18, 2009)

Question for you guys, does an anti-ventilation plate apply the same stern lift that a hydrofoil does? I'm getting a little prop ventilation at my current motor height, but with the trim tabs installed now I do not want to apply another stern lifting device, but I'd like to give one a go to channel some water back to the prop and water pickup without having to lower my engine.

Steve


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## cutrunner (Jun 8, 2010)

This will b good [smiley=popcorn2.gif]


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## topnative2 (Feb 22, 2009)

grind a tunnel into the hull


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## Chevystroked383 (Apr 12, 2011)

Try more Cup 
and different blade designs how high is the motor mounted


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## Brett (Jul 16, 2008)

Hydrofoil is for use on outboards mounted with the anti-ventilation plate just below the the bottom of the transom.
Compression plates are intended for use on outboards that are set up to run with the anti-ventilation plate above the bottom of the hull.
Compression plates are designed to keep water in contact with the propeller tips and prevent blowout.
Especially useful on tunnel hulls to channel flow from the tunnel to the prop.
Both foils and plates provide lift. The amount of lift varies in proportion to surface area and trim angle.

Hydrofoil brands are Doel-Fin by Davis Instruments, Stingray by Marine Dynamics, and
SE Sport from Marine Technologies.

Compression plates are fabricated by machine shops and offered in conjunction with their jack plate sales.
I've seen some built of molded fiberglass, installed by hull builders to fit their specific hull.


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## topnative2 (Feb 22, 2009)

pictures pictures >>never heard of a compression plate>sounds interesting


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## Brett (Jul 16, 2008)




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## SClay115 (May 18, 2009)

Brett, as always, thanks for the informative reply. 

And to clear things up, I am not attempting to lift the motor so the prop is on the second floor. It was just a simple question. The factory cavitation plate is level with the bottom of the transom. Nothing crazy, I made a change to the hull and am trying to do some diagnostics. 

Steve


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## backwaterbandits (Dec 15, 2006)

I use a Bob's Tru-Tracker to help hold water
around my prop. It is a small unit and adds
little if any lift.
I have a Yammi 25 2 stk. with a 4 blade 
cupped prop on a Bob's manual/fixed plate
that stays all the way up. This set up has
worked very well for me.


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## SClay115 (May 18, 2009)

> I use a Bob's Tru-Tracker to help hold water
> around my prop. It is a small unit and adds
> little if any lift.
> I have a Yammi 25 2 stk. with a 4 blade
> ...


Thanks for the tip, checked it out through google, looks like what I'd be shooting for. Just something to extend the running surface of the factory plate. Reasonably priced too.

Steve


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## noeettica (Sep 23, 2007)

I an working this up this is the Prototype ...


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## kaioticone (Aug 1, 2010)

anti-ventilation = correcting blow out? I have Pathfinder 17T which tends to blow out a bit in the shallows, when jumping on plane. Sure I could drop the engine down and tear up the bottom, but I, simply won't do that.

Surely a cavitation plate would not be a poor addition to any outboard engine. Just make sure you get one produced by a reputable company. Bob's Machine (http://www.bobsmachine.com/products/transom_stabilizer.cfm) seems pretty reputable.


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