Dual outboard controls and counter rotation for vintage omc motors

Jdunham

Seaman
Joined
Sep 9, 2015
Messages
56
Hello,
I have been considering a project for a while now and it is time for me to ask for some input.
As always, I like to start with an ideal and then settle for less when it turns out to be impractical.

I want to run twin 30hp or 35hp vintage OMC motors (56-59) on a larger aluminum hull. Something in the 19-22' range, I dont have the boat yet.
I understand that if possible one should have a left hand prop on it to balance the torque steer.
As far as I have found, there was no factory option back in the 50s/60s for these motors to be set up like this.

There are a couple of big hurdles that I see.
First is the expense of a non-through hub exhaust, pin drive, left hand prop. I doubt there is one on a shelf so it would likely need to be custom. Lets ignore that issue for now.
The second is the counter rotating lower unit. I think the simplest way to accomplish this is to use a standard lower unit and run one set of shift controls out the front of the control box. It can then either loop under the bow deck or just run down the other side of the boat.
This would put one motor in reverse and one in forward with both shift levers in the same position.
This would then create the issue of loading the wrong side of the teeth in the gear set. I know they are stronger in one direction, but how much stronger?

Has anyone already worked on this?

The simple answer is of course to just let them both spin the same way and use right hand props....but what is the fun in that?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,047
Will not work.---Forget it.----And why would it load the wrong side of the gear
 

Jdunham

Seaman
Joined
Sep 9, 2015
Messages
56
Why wont it work?

One of the lower units would always be running in reverse. Loading the reverse gear and producing forward thrust. Not sure the bearings are set up to take that.
You are correct, the teeth wont see any different load, the driveshaft still spins normally.
 
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