This boat likes to go right!

[Rstacy]

The boat is 79 Baja with a Merc 900. Let go of the wheel and it will turn right all day long. The higher the speed the quicker the turn. Turning left can require two hands!
I did the research on this site and found that the trim tab on the outboard will help this. The problem is that the previous owner cut the tab off to make room for the prop!
It isn't torque that makes the boat want to turn.
What phenomena is it?

 

[alldodge]

What phenomena is it?

The rotation of the prop causes it. If it was twin prop where one turns clockwise and the other counter clock wise they would cancel each other out. Same thing causes a boat with a single prop to go to the left when backing up.

You need to replace the anode tab and get one which sits to the rear, or grind some off to clear

http://www.iboats.com/Replacement-T...843056--session_id.162734360--view_id.1104762

 

[Sea Rider]

On single OB installation with prop rotating clokwise, center console, dashboard & wheel are always set up on the right side, driver's weight and trim tab correctly adjusted will compensate for boat not turning left...

Happy Boating

 

[Rstacy]

On single OB installation with prop rotating clokwise, center console, dashboard & wheel are always set up on the right side, driver's weight and trim tab correctly adjusted will compensate for boat not turning left...

Happy Boating

​That adds up! I am the heavier of the two people in the boat. It did turn left better with me in the drivers seat.

​

You need to replace the anode tab and get one which sits to the rear, or grind some off to clear

Why is it important to have this anode tab?

 

[alldodge]

Why is it important to have this anode tab?

Adjust it to balance load

Let go of the wheel and it will turn right all day long

You have torque steer

 

[Rstacy]

Thank you guys!

 

[jimmbo]

An engine trimmed all the way down will cause the steering to pull to starboard, trimming out will reduce and eventually eliminate it. Trimming further out an it will pull to port. The crankshaft is spinning one direction, the block is going to try spin the other direction, Newton?s 3rd law. With the crank sponge clockwise when viewed from above, the block will be trying to spin counter clockwise, which means the rear of the engine will be swinging to starboar. As mentioned there is an adjustable trim tab p, but it affects the torque differently depending on rpm, trim angle, and prop design