Boat Pulling Right OR Engine Pushing Right

[bobgritz]

I'd go around in circles if I didn't strongarm my tiller handle. The engine is a 1968 9.5hp Sportwin and the boat is a 14' Starcraft.

It's likely a trim problem and not a hull problem since the boat rode true with a previous motor that I just pulled off. I need to emphasize that it's not a slight pull to the right but a pretty severe case.

 

[boobie]

Re: Boat Pulling Right OR Engine Pushing Right

Did you try tightening down the steering friction lock on it ??

 

[bobgritz]

Re: Boat Pulling Right OR Engine Pushing Right

The steering friction bolt is spinning and can only be mildly tightened. It appears that a previous owner must have stripped the nuts and then re-drilled holes (that secure the steering friction plate). The re-drilled nuts are buried in the base of the motor cover and seemingly impossible to access. Yes, ultimately I need to somehow pull the mechanism and repair it but, the amount of pull-to-the-right seems way out of proper proportion.

Perhaps this is normal but it seems that a tremendous amount of forward power (and speed) is being lost due to the apparent 'crabbing'. I can understand needing a small amount of trim but how does one know how much is normal and when there is too much.

 

[boobie]

Re: Boat Pulling Right OR Engine Pushing Right

Really dumb question. Is the skeg bent on the mtr ??

 

[sschefer]

Re: Boat Pulling Right OR Engine Pushing Right

Really dumb question. Is the skeg bent on the mtr ??

No at all dumb. If there is supposed to be skeg on the cav plate and its been broken off, cleaned up and repainted you'd never know until you ran it. Might even be missing part of the skeg on the lower unit that's been cleaned up and repainted.

See if you can find a pic of what the lower end of the motor is supposed to look like. That might have a replaceable annode skeg on the cav plate that's been removed or replaced with a washer or a non-skeg annode.

 

[boobie]

Re: Boat Pulling Right OR Engine Pushing Right

I was talking about the very bottom of the lower unit. There is no trim tab on cav plate of that mtr.

 

[bobgritz]

Re: Boat Pulling Right OR Engine Pushing Right

SOLVED:

All great thoughts ... thank you. It turns out the Boob was on the right path. My motor was freely rotating from side to side with little or no tension from the steering friction mechanism. Once I managed to get the bolt to tighten, the outboard stiffened on its axis and the boat no longer 'appears' to pull to the right.

However, although I have tightened the steering friction mechanism of the motor, you realize that there is a tremendous amount of sideways force created from the rotation of the motor's propeller. It seems to me that every prop-driven boat would travel in a circle if there was no trim mechanism in place. It also makes one wonder how much forward energy is lost due to the need for the boat to be forced against the 'crabbing' effect caused by the props torque. In other words, you are probably losing about 10% +/- energy (hp) due to the need to force the boat in a forward direction. I imagine that a jet ski type of propulsion would have less wasted power due to a purer flow pattern of thrust. Just a thought!

In any event, my boat is traveling in a forward direction albeit ... against it's will!

 

[boobie]

Re: Boat Pulling Right OR Engine Pushing Right

You need a g/c with dual counter-rotating props. LOL.