Major handling issues

stant1man · Oct 8, 2005

I have a Fletcher GTO Bravo 17ft with a Mercury inline 1350 outboard. It has a 18p x 13 stainless prop. The skeg is pretty knackered and was that way when I bought the boat. It does a top speed of 47mph.... When cruising along at any speed over 30mph it seems to sway side to side at the back. If i try to turn it gets worse and it feels like a snaking trailer. If I trim my engine down it turns violently right if i trim it up I have to steer to the right to keep it from going left!!! Whats going on here? Is it my skeg or something else. When trimmed right out if I was to let the steering wheel go it would turn left violently... I have been told that a skeg doesn't really serve any purpose, is this true? Advice appreciated.... Stan

Boomyal · Oct 8, 2005

Re: Major handling issues

Not an outboard expert Stant1, but I would consider two maybe three issues. If the skeg is distorted enough it could cause directional issues. Outboards must have an adjustable 'trim tab' that helps in neutralizing prop torque. It is usually under the cavitation plate, above and to the rear of the prop and it is adjustable. Lastly, do you have any kind of fin/wing attached to the OB cavitation plate? This could be a big issue.

stant1man · Oct 8, 2005

Re: Major handling issues

Thanks for the prompt reply Boomyal, I have no fin/wings on my cavitation plate and the trim tab is adjusted to its maximum to try and help but does little....

CalicoKid · Oct 8, 2005

Re: Major handling issues

Check and see if there is any play in the steering or tilt by pushing and pulling on the motor while the boat is up on the trailer. Make sure your motor is mounted square and level on the transom and that your transom is not rotted.

KCook · Oct 8, 2005

Re: Major handling issues

I agree with CalicoKid. First thing to check for is looseness in either steering or motor mount. Kelly Cook

TD_Maker · Oct 8, 2005

Re: Major handling issues

Stant, The skeg does serve a purpose. The skeg works much like a horizontal stabilizer does on an airplane. It helps to control the yaw affect of an outboard motor and stabilizes it whether running straight or in a turn. This would explain the wild turning flucuations you are getting when turning or trimming. True, you do not need the skeg to run the outboard, but you will need to muscle the steering and pay constant attention to the wheel when under power. Be thankful you do not have a 200 merc to fight with!

LubeDude · Oct 8, 2005

Re: Major handling issues

Originally posted by stant1man: IIf I trim my engine down it turns violently right. Advice appreciated.... Stan

With your trim tabs adjusted all the way down, you are forcing your bow into the water and causing bow steer. Just a hunch, but I think you engine is mounted way, way too low. Where is you ventilation plate in refference to the bottom of your boat?

stevens · Oct 9, 2005

Re: Major handling issues

When cruising along at any speed over 30mph it seems to sway side to side at the back. If i try to turn it gets worse and it feels like a snaking trailer.

That sideways wobble might be what they call chine walking. Trim tabs will help counteract this, and you will find that a lot of people on this forum (myself included) are very happy with their Smart Tabs from Nauticus . That beat-up skeg of yours can easily be fixed with a Skeg Guard from Skeggard Marine . One more thing; you say above that "if i trim it up I have to steer to the right to keep it from going left" and also "the trim tab is adjusted to its maximum to try and help but does little". That trim tab may have been adjusted to the wrong side, in fact causing or exasperating the problem. Maybe you should try to set the tab back to its neutral setting and see if this helps any.

stant1man · Oct 9, 2005

Re: Major handling issues

Thanks for all the advice guys. Hard to get things like Smart Tabs and Skeggard's here in Scotland. I have a couple of issues that I have to address then. There is a little bit of play in my steering, though I dont think this the major issue... Engine height... What should it be? The plate directly above the prop sits approximately 1 inch above the bottom of the boat, is this too high? Many thanks Stan

TD_Maker · Oct 9, 2005

Re: Major handling issues

I said horizontal stabilizer. I meant vertical stabilizer or tail fin. Sorry

stevens · Oct 9, 2005

Re: Major handling issues

I have both the Smart Tabs and the Skeggard, and I am in Norway. Easy to get over the internet, and there are retailers that ship worldwide, like Overtons .

stant1man · Oct 11, 2005

Re: Major handling issues

Originally posted by stant1man: Engine height... What should it be? The plate directly above the prop sits approximately 1 inch above the bottom of the boat, is this too high?

Anyone any ideas, is there like a rule of thumb?

CalicoKid · Oct 11, 2005

Re: Major handling issues

You're probably about right height wise. Generally a good place to start is with the anti-vent plate even or a bit above the bottom of the hull and raise it a little at a time for best performance. You could lower the motor and see what happens but things will probably go downhill. Do you have a photo of your skeg? If the little trim fin makes a difference in handling imagine what a bent up skeg will do. Also you shouldn't have any slop at the motor mounts steering or tilt pivots. A little in the steering wheel is OK but not at the motor. Which way is your trim fin pointing, left, right, or center?

stant1man · Oct 11, 2005

Re: Major handling issues

I'll see if I can take a picture of the skeg and post it here. It bends to to the left about 5 degrees and is also twisted. The front of it is mushroomed from impact. It was like this when I bought the boat but was told not to worry about it. I was tempted to just cut the thing off and leave a couple of inches until i can have a new one fabricated or until I get a Skeggard. My concern with getting a skeggard was that it may have a wider profile than the original, would this not slow the boat down. Whats the best way to go... Skeggard or repair... There is no play in the swivel bracket or trim, at least not that you wouldn't expect. There is a little play in my teleflex. I replaced the swivel bracket bushes as part of my rebuild as there was play there so that problem no longer exists. What should be my first course of action? Regards Stan

stevens · Oct 11, 2005

Re: Major handling issues

I'd try to straighten and flatten the skeg you have, but be careful not to break it off. The Skeggard needs at least a few inches to screw on to, and the more the better. Yes, the Skeggard is a little thicker than the original skeg as it goes on the outside of it, but I wouldn't worry. It is still a very slim & streamlined profile and I can't believe it would have any effect at all on performance. Here's what I would do; - fix the existing skeg - add a Skeggard if needed - straighten the trim tab above the prop - do some test runs - probably add some trim tabs - play around with tabs & trim & weight distribution, until it runs straight and stable Good luck!

CalicoKid · Oct 12, 2005

Re: Major handling issues

If you can't fix the skeg yourself then have it done for you, yes a bent skeg will affect your handling a lot. That would be the first atep I would take.

stant1man · Oct 14, 2005

Re: Major handling issues

Thanks for all the advice guys. I've contacted the local engineer that carried out some work on my powerhead and he said that he could fix it so that I would never know it had been damaged! And all for £60. Probably a good price since i've went to him before. I've also ordered a set of smart tabs so hopefully all my hangdling issues will be sorted soon! Time and testing will tell.. I'll let you all know how it goes... Many Thanks Stan

stant1man · Oct 21, 2005

Re: Major handling issues

Lower unit is now off and the skeg is being re-worked at the engineering shop. I have since discovered that whoever mounted my engine, mounted it slightly off centre of the transom. Probably about 1.5 inches to one side. Would this cause me the problems I am describing? Thanks Stan

jtexas · Oct 21, 2005

Re: Major handling issues

skeg serves two purposes: 1. protects the prop from contact with the bottom of the lake or the boat ramp

, and 2. functions as a tiller, as TDmaker says, like a vertical control surface

deerhound · Oct 31, 2005

Re: Major handling issues

May I ask which way to set the trim tab off a little before trying boat (left or right)my prop is right handed, clockwise, JBD

Major handling issues

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