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Capt Frank Hopkins
 
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Default Hydrofoils


Hi JP,

Hydrofoils like anything else, have their pluses and minuses. On a bigger
boat like yours, a small foil won't do much good. You need a large (26"-35"
pre side) non-flexing unit installed with 20 + - degrees of dihedral. The
problem is, hydrofoils don't work well at low speeds. They need 12+ mph of
flow to begin generating a significant lift. At 25+ mph, the foil will
really provide a lot of lift at the stern (forcing the bow down), usually
requiring the trim to be kicked up at a very high angle. This causes a
certain amount of prop slip and loss of efficiency.

You are generally better off with a set of hydraulic trim tabs. I use
Bennett 191421 tabs (12"X12") on my Formula 26 PC. They give me a good hole
shot and allow me to level the boat at planing speed when the passengers
move around.

You can order them from West Marine
http://www.westmarine.com/webapp/wcs...play?storeId=1
0001&langId=-1&catalogId=10001&productId=14663

OR Boatfix.com

http://www.boatfix.com/elec/bentt.asp

Which is a little less expensive.
--
Capt. Frank

__c
\ _ | \_
__\_| oooo \_____
~~~~|______________/ ~~~~~
www.home.earthlink.net/~aartworks
"JP" wrote in message
...

Are the after market Hydrofoil wings that are attached to Outboards
and I/Os any good? If they work as advertised, why don't the
manufacturers install them? Are they worth the money and will they
harm my boat or my engine??
I have a 23' Sea Ray with a 350 Mercruiser fuel injected engine. I
want it to get up on a plane faster. Will Hydrofoils work?
Anyone have any experience with them?
Thanks




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RichG
 
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Default Hydrofoils

I've used them on 4 boats and had excellent results with them every time.
The largest boat, however, was a 20 ft. Gulf Coast ( Boston Whaler copy )
with a 150 hp o/b engine. All 4 boats...had jack plates and/or engine
extensions.

Most people say that they work well; however, they cost you some top end
speed, and that tabs are better for many applications.

Do a search on www.Google.com for Bennet; Lenco; and Smart Tabs, and you
will find many discussions, both pro and con, on these three different
approaches to tabs.
--
RichG
http://groups.msn.com/CarolinaSkiffOwners


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Lawrence James
 
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Default Hydrofoils

Adjustable trim tabs. Best investment you'll ever make related to your boat
performance.

"JP" wrote in message
...

Are the after market Hydrofoil wings that are attached to Outboards
and I/Os any good? If they work as advertised, why don't the
manufacturers install them? Are they worth the money and will they
harm my boat or my engine??
I have a 23' Sea Ray with a 350 Mercruiser fuel injected engine. I
want it to get up on a plane faster. Will Hydrofoils work?
Anyone have any experience with them?
Thanks



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Rod McInnis
 
Posts: n/a
Default Hydrofoils


"JP" wrote in message
...

Are the after market Hydrofoil wings that are attached to Outboards
and I/Os any good?


They can be. If a little bit of lift will benefit the ride of the boat then
the hydrofoil can be a great help. If the boat is just too heavy or its
basically balanced well to start with then the hydrofoil will just add drag,
slowing the boat down.

If they work as advertised, why don't the
manufacturers install them?


Their value is dependent on the entire installation, including the boat. If
you didn't need the lift you sure wouldn't want the added cost and drag
associated with the hydrofoil.


Are they worth the money and will they
harm my boat or my engine??


If it improves the performance then it is probably worth it. If it does
nothing for you then it was a waste of money. The lift that the hydrofoil
provides is applied directly to the outdrive, so it will put an added strain
on the outdrive unit and transom. I have never heard of this causing a
problem, however.

I have a 23' Sea Ray with a 350 Mercruiser fuel injected engine. I
want it to get up on a plane faster. Will Hydrofoils work?


My gut instinct would say no. You should have power trim, so you should be
able to tuck the outdrive far enough up that the thrust can provide lift.
Have it trimmed this way to get on plane then ease the trim out once you are
going. On that large of a boat, with that heavy of an engine, I would think
the hydrofoil would be only a drop in the bucket.

Anyone have any experience with them?


I have one on my 12' inflatable, powered by a 9.9 Hp outboard. The result
is noticeable, but not dramatic. It makes a difference getting the boat on
plane with four adults in it.

Like someone else suggested, Trim tabs would be a better choice for you.


Rod


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