Whaler Central - Boston Whaler Boat Information and Photos

Posted by gigem on 12/01/08 - 9:33 AM

Boat is a 1977 Outrage 21. Motor is a 1996 Evinrude OceanPro 175. Boat DOES NOT have hydraulic steering.

While underway, boat requires a constant hand to keep it from steering hard to starboard. I know that hydraulic steering can help address this, but that's outside of the budget for now.

Questions:

1. What is that little adjustable tab on the lower unit behind the prop called? I've seen it called a prop thrust tab, a torque tab, a trim tab, etc.

2. With the motor trimmed down, visualizing this tab from above, adjusting this tab to move the front edge to the right (clockwise) should make the boat want to steer more to port, correct?

3. Realistically, with this sized boat and motor, should I be able to get the boat to track fairly straight by just adjusting this tab?

Thanks for your thoughts on the subject.

Edited by gigem on 12/01/08 - 9:34 AM

Posted by Derwd24 on 12/01/08 - 10:29 AM

In the parts diagram it's called a Trim Tab, Gearcase, but to distinguish it from the boat trim tabs, I call it the Gearcase Trim Tab.

To adjust it properly, you want to move the back edge of the tab in the direction the boat is pulling, which in your case is starbd. Makes sense when you think about it as this exerts a force on the rear of the gearcase to port, which is what you're doing with the steering wheel to compensate.

Two other things to check are the condition of the skeg on the bottom of the lower unit for bend or twist. Second thing is proper engine height on the transom as that can have some influence on steering effort. Give this article below a read:

http://www.veradoclub.com/smf/index.p...opic=137.0

Posted by Paul Graham on 12/01/08 - 6:55 PM

Not sure what would fit our budget, but for approx. $250 you can install a Teleflex no feedback sngle cable steering system, your wheel will stay where you stop it. I have this set up and do not have to fight the torque of the motor

Posted by Derwd24 on 12/01/08 - 7:50 PM

Bob, If I understand your post correctly, I think you have it backwards. Moving the trailing edge to port of centerline will increase the engine pull to stbd. not decrease it.

Posted by Tom W Clark on 12/01/08 - 8:23 PM

Yes, move the trailing edge of the trim tab to starboard if the boat tends to pull to starboard.

Both NFB and hydraulic steering will *help* mask the pull but will NOT eliminate the torque causing the pull. Treat the problem instead of the symptom.

It is very important to compensate for steering toque with the trim tab regardless of what type of steering system you have.

New mechanical steering systems cost hundreds of dollars. Hydraulic steering can be a thousand dollars or more. The cost of adjusting the trim tab correctly is zero.

Edited by Tom W Clark on 12/01/08 - 8:27 PM

Posted by Barryg on 12/02/08 - 4:39 AM

It should cost zero but if it is like mine the bolt is seized. I broke the head off trying to remove it. I have no trim tab at this time and the boat does pretty well. I keep waiting for some great advice to get this bolt out. I have tried heat, a $28 dollar bottle of Corrosion Block and several bouts with the Channel Locks. That salt water is tough. BG

Edited by Tom W Clark on 12/02/08 - 9:09 AM