Counter Rotating on Cats
 

I have a question for the Cat guys out there....Is it important to counter rotate the engines on cats with big power? I am talking boats like Skater, MTI, etc...

I am just curious...thanks.

Engines=NO
Drives=YES

On the early Arneson Cats we reversed rotation on one engine.

Thanks, Griff...That's what I thought....

Now, with Arnesons or BPM drives, is it the drive that does this, or the transmission?

That is a question for Rik in those days the drives were turned whatever direction the input shaft was turning and there were no reversing transmissions that could take the power and RPM of the racing Engines which BTW they did not seem to mind what direction they turned.

No we always had a reverse rotation motor and the Dyno pulls showed not much difference no more that you would see between two standard or left hand rotation motors.

Which is great for the port side but what do you do for the starboard side? You need a right hand rotation motor.No Biggie.


Bear in mind this was when we had a crash Box connected Via a Jack Shaft to a drop case on the transom with the drive on the bottom of it no reverse rotation was built into it.

Beautiful setup, engine torque was perfectly balanced and you could spin the drive over with your fingers the drop box had ATF in it low loss Mr Arneson hid a great job on it. But That was then. Arneson #6 Boat Fayva Shoes Cat #2 The Surgen. everything that ran out front in those days.

I was talking to a guy today who makes 2-speed transmissions for performance boating and he mentioned that his transmissions can't counter rotate, so I was just wondering if this is a function of the motor, transmission, or drive....I am pretty new to this stuff, as you can see...lol

With Arneson's the drive is what determines the rotation...At least on ASD-7M's it is...One is gear driven and the other is Chain driven...

Cool....do you know if its the same on BPM drives?

Not sure if Rik Wimp is around I'm sure he has the answer...He's the expert....I'm just a customer and very happy with my Arneson's...:drink:

The Arneson's have counter rotating in the drive as do the Drop Box BPM gear boxes. So you can run two standard rotation (assuming it is a twin engine boat) engines and have counter rotating propellers.