hydrofoil for "getting on plane faster"

bryancx94

Seaman Apprentice
Joined
May 22, 2006
Messages
43
I am considering purchasing a hydrofoil to get my boat on plane quicker, I have a 94 90HP mariner on a 16' fiberglass vhaul starcraft. I took it out yesterday and it takes about 14/ to get it on plane, then once on plane it gets up to about 40mph (top speed) no problem.

My question is, will a hydrofoil help this issue. Also is there anything I can do to get more speed out of my engine. I remember when it was brand new it was able 50mph hit 50mph. The prop is aluminum 3 fin, and in good shape. Thanks!
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: hydrofoil for

Re: hydrofoil for

I'd find the source of the power loss before throwing gadgets at it. Make sure it's running on all three. Sounds like one cylinder is on holiday.
 

bryancx94

Seaman Apprentice
Joined
May 22, 2006
Messages
43
Re: hydrofoil for

Re: hydrofoil for

yeah I was going to do that.. since a hydrofoil is afforable i thought it wouldn't hurt since the engine is a little bit older.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: hydrofoil for

Re: hydrofoil for

As Willy says check the motor for performance issues.
Could be as simple as a bad sparkplug.I've had good luck with foils but they should be considered a last resort after tuning,trimming and balancing weight.
And then you should seriously consider the Smart Tabs.A much better solution to performance issues.
Your motor isn't performing poorly because of age it has
some sort of problem.
 

bryancx94

Seaman Apprentice
Joined
May 22, 2006
Messages
43
Re: hydrofoil for

Re: hydrofoil for

My boat says a max of 825lbs ... I noticed yesterday anything over 500lbs it would barely get on plane, is this normal? its a 3 cyc engine, I had two people in the front, and it would still not get on plane. I will check the spark, on all three plugs ... what do u think top speed should be on that boat?
 

bryancx94

Seaman Apprentice
Joined
May 22, 2006
Messages
43
Re: hydrofoil for

Re: hydrofoil for

I saw the smart tabs for about $175. Are they a lot better than a foil? are there any negatives about installing a foil on my engine?
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: hydrofoil for

Re: hydrofoil for

Lots of negatives. Every time you touch the trim button or turn the steering wheel, the hdyrofoil's characteristics change. Tabs stay put and don't mess with your handling. Hydrofoils also slow you down by 2 to 4mph, tabs don't slow you down at all. In fact they can even help the boat go faster.

You might be overpropped. 40 is about what I'd expect. Check your prop's pitch. Educated guess would be a 19" for speed and 17" for power. 15 would probably be too low and 21 too high. But it all depends on the boat and motor setup.
 

bryancx94

Seaman Apprentice
Joined
May 22, 2006
Messages
43
Re: hydrofoil for

Re: hydrofoil for

So with the smart tabs installed, you still use the motors trim as normal? As for the props pitch, is there a way to measure it so i can see what it is?
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: hydrofoil for

Re: hydrofoil for

Props usually have their dimensions or a part number stamped or embossed somewhere on them. Tabs can allow you to trim the motor higher (a bit) which could give you more speed. They can also wipe-out any porpoising problems.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: hydrofoil for

Re: hydrofoil for

get a manual and start trouble shooting. it use to run 50mph, it still should. either the engine is sick or the boat is sick(wet foam).
 

Dead Eye

Petty Officer 1st Class
Joined
Jan 21, 2004
Messages
259
Re: hydrofoil for

Re: hydrofoil for

Put one on ny last boat. 18ft wellcraft W150/ MERC. Got up on plane better and stayed on plane at lower rpms. I liked what it did for me. May have lost some? at top end but saved fuel on plane at lower speeds. Wasn't' pushing water.
Dead Eye
 

phatmanmike

Captain
Joined
Oct 24, 2003
Messages
3,869
Re: hydrofoil for

Re: hydrofoil for

you are not listening to anybodys advice.

stop thinking about tabs or fins, and find out what is wrong with your motor and or boat first.

if it used to go 50, it still will if all is good.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: hydrofoil for

Re: hydrofoil for

check your plugs, and spark, compression, you may need some carb attention, linc n sinc. the engine has to be healthy first. then if you still have problems getting on plane go to the smart tabs. i personally think foils are the ugliest thing you can put on a boat. it also yells i have a bad performing boat, and i'm too cheap to fix it right.
 
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