Is the Trouble a Bubble????

[Scubado]

We have a weird problem with a 1966 18' Classic (port steering) with a Volvo 280 Drive. After you come up on plane it is very difficult to steer. It's as though there is a bubble or some sort of turbulence created that makes it hard to turn the steering wheel. If you turn the drive quickly and sharply the problem goes away instantly, it is once again easy to turn the steering wheel. It has us stumped, any ideas???

Oh, and we've tried different props and it has no affect.


Thanks,
Jeff :confused:

http://www.donzi.net/photos/leipham_001.jpg

http://www.donzi.net/photos/leipham_003.jpg

[mattyboy]

first let me say nice ride Scubby!!!! :D
things I would check, the steering cable any play or slop when idling or a rough spot when turning?or play in the tiller arm.it sounds like it is only when the drive is under load that it happens,I had some play in my setup and when i loaded the drive it would take the play out and wedge in place a little then needed to be muscled out.
check your torque tab, I thought mine wasn't straight so I straightened it out, WOW now i know why it was slightly turned to the right,
I'm not a wiz kid I'm sure the guru's will have some other help
I just noticed that your trim tab appears shorter than mine, I might need to be a little longer to help counter the torque from the prop??
Matty

[AVickers]

By "difficult to steer" do you mean that the wheel doesn't turn easily and when you jerk it, it begins to work ok? Or the wheel turns, but the boat doesn't respond?

How long has this been going on?

If the wheel is difficult to turn and this has just started, my guess would be that there's something binding somewhere. If it's an original helm, perhaps it has a broke or bent gear tooth or the cable is streched or compressed.

The prop you have on now doesn't appear to have much rake -- which provides bow lift. This could cause the boat to plough and make turning less nimble than if the bow were out of the water... I don't know that this would cause "difficult steering." Just not as responsive as it should be.

[CDMA]

Is it just me or does the Torque tab look really out of line?

Chris

[BUIZILLA]

I'm with Chris' opinion....

J

[boldts]

Another thing I'm noticing, is there appears to be an aweful lot of cavitation going on with that prop. (Introduction of air bubbles that explode on the prop blade) Prop probably has a lot of slip and not working very efficiently?

So, do I have this terminology correct or did I forget everything I learned at AOTH III? :) I can't remember which side, but the speedo pick-up will introduce air into the prop also. We learned that it was best to be placed on a certain side of the transom depending on which way the prop was turning, but I can't recall what the rule was. That is one very pretty Barrelback 18 Classic.

Scott
Nothing causing air on my transom :D

[Scubado]

Thanks for the replies guys!

Ok, more info:
This has been going since we changed out the Eaton Drive many years ago .
There is noo play in the steering cable.
It turns smoothly throughout it's turning radius (no rough spots)at all speeds.
The torque tab is about 10 degrees or so out of line (I'll measure it for sure when I get home) It drives straight though when you release the wheel.
When I say it's difficult to steer, it's like driving a car that has a powersteering pump that has gone out. Smooth but it takes muscle to turn the wheel.
A quick turn to the of the wheel left or right cures the problem every time. But it has to be enough to move the boat into a turning angle (put the boat on edge) Turning slowly does not.
There is a lot of cavitation as evidenced by the condition of the prop, that's why I am wondering if there is some kind of air buble traped in front of the drive or crazy water turbulance???

Thanks everyone for your feed back so far, I'm sure we can get this thing figured out. It's just had us completly stumped...

[BillG]

Sounds like torque steer or the cable from the front is worn through to the outer sheath. I had tremendous torque on the wheel until I got a high raked wheel on the boat. No more torque steer.
If you had a bubble the prop would be in it and you would go nowhere. My speedo pickup is in the same place and is not a problem.
Bill G

[EricG]

Although I can't offer any advice....I wanted to pass along to the others reading this thread...that this 18 is a Museum Piece. We spent Sunday running with Jeff and his family, including his dad in this 18. 3 hatch, Original Gel, Original interior...and damn did it go! If he was having steering issues...I sure couldn't tell.

I'll have lots of pics of the gathering posted tonight....

Now back to the fun...

EG
-Did I mention that I'm looking for an 18 :D

[AVickers]

That prop looks like something from a houseboat -- no rake and no cup and big ole elephant ear blades. Great for displacement hulls, not so great for planing hulls. There are immediate implications for handling in that a prop w/ no rake provides little bow lift. Seems like your hull is in the water and the deep-V is acting like a rudder -- only it's way out in front of the prop instead of close by.

Donzi hulls move a lot of air under and you can air out a prop in no time. I'd try to find a prop for a high performance planing hull boat and see what happens.

Also, you might try to change the location of the trim pin to the outermost hole to try to get the bow up.

One other thing. Have you checked the X-dimension? That drive might be a bit high on the transom... The cavitation plate looks to be a bit above the drain hole.

[mphatc]

How tight are all the steering pivots and mounts on which the unit swivels when steered?
I experienced the same symptoms with a Mercruiser Alpha that had a worn out gimbal ring. This happened when the outdrive went out of alignment from the hull under hard acceleration, and a quick swerve left right cleared the "helm".

FWIW, I compared the transom bracket location of your 18 in relationship to the waterline to my Corsican, As best I can tell they are the same. I am unsure of the cavitaion plate height diference between your drive and my 250.

Let us know what you find!
Mario L.>

[BigGrizzly]

That is a left turn prop. try putting the tab on the other side. Mine runs on the other side. I knoe what your saying -the faster yu go the harder it is to turn.

[MOP]

From the photo I think Griz hit the problem on the head, tab is set for right hand prop. When the boat is on the trailer get a buddy to put fairly decent pressure on it to keep it from turning then using the wheel turn it slowly, do it in both directions it will help you feel bindy spots also the drive should with some effort be able to be turned by hand with the cav plate smoothly in both directions. A dry helm needing grease will also do this, they are a pain to open, clean and re grease but worth the time, I do mine every other year.

[Moody Blu']

Yes the tab looks wrong, but even with it set correctly it will be harder to steer the faster you go, thats the one draw back of manual steering. None the less, think of it as a work out for your arm. right arm on the wheel left hand on the throttle and pump that baby! :p