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motor rotations

Old 05-23-2020, 12:09 PM
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Ready to repower my 26 ft Glacier Bay Cat boat and wonder if it's necessary to have one motor be a counter rotating . Currently I have one standard rotation and one counter rotation and they work fine. Anyone with first hand experience with both ways?
Old 05-23-2020, 02:08 PM
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Well, having owned a twin engine rig with counter rotating props, it's my understanding it's at least preferred to avoid excessive torx on one direction. If someone much more knowledgeable then you or I doesn't post on your thread I suggest you google "the need for counter rotating props" and see what you learn.
Old 05-23-2020, 03:41 PM
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Counter rotation is not as critical on a cat as on a mono, but, if there's a choice, go for the counter rotation, it's just nicer.
Old 05-23-2020, 04:48 PM
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I had a Scrab without counter engines. The boat ran fine but out of the hole you had to ease the throttles or the props would have bad cavitation . I doubt a factor on a Cat. If the price is right on a part of same engines , I would not hesitate.
Old 05-23-2020, 07:23 PM
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It's about $450.00 more for a counter rotating motor. Not sure why.
Old 05-23-2020, 07:24 PM
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Originally Posted by joro2548 View Post
It's about $450.00 more for a counter rotating motor. Not sure why.
spend the money
Old 05-23-2020, 07:27 PM
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Spend the money, counter rotating screws handle better around the dock. It's more money because there's an extra gear to make it spin the other direction.
Old 05-24-2020, 07:26 PM
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Thanks eveyone for the input. I believe I will go with the counter rotating motors.
Old 05-25-2020, 07:03 AM
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Cats place the motors far enough apart to negate the need for counter rotating drives.
Old 05-25-2020, 07:10 AM
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Originally Posted by joro2548 View Post
It's about $450.00 more for a counter rotating motor. Not sure why.
Save your money and get two identical motors. Plus, you only need to carry one spare prop. The wide spacing of the motors on a cat negate the need for counter rotation.

I used to run a Glacier Bay with twin Yamahas with standard rotation. No issues
Old 05-25-2020, 07:28 AM
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Originally Posted by SaltyDawg86 View Post
Spend the money, counter rotating screws handle better around the dock. It's more money because there's an extra gear to make it spin the other direction.
Unless you buy Suzuki I believe. The 250 hp's & up's lower units can spin in either direction, plus you can change it back to standard rotation for resale.
Old 05-25-2020, 07:53 AM
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Originally Posted by SaltyDawg86 View Post
because there's an extra gear to make it spin the other direction.
Contrary to popular belief,
standard, and counter-rotating outboards have the exact same number of gears: 3
One driveshaft gear,
one 'driven' gear used for forward,
one 'driven' gear used for reverse.

The main difference between them,
is which of the two driven gears the shift shaft engages,
when the remote control is moved.

And the bearings supporting the gears are different;
whichever gear is used for forward,
must withstand, continuously, the full horsepower of the engine,
while the gear for reverse carries only a very small amount of load,
for a very short time.

Some Suzuki engines are designed such that either driven gear
can handle the full continuous load of forward motion.
Old 05-25-2020, 08:07 AM
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Originally Posted by joro2548 View Post
It's about $450.00 more for a counter rotating motor. Not sure why.
Two things would come to mind, less production numbers on the one and because they can charge more because the manufacture knows you've got the money for two engines and therefore they can charge you more.
Old 05-25-2020, 10:18 AM
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Originally Posted by Fwpratt View Post
Contrary to popular belief,
standard, and counter-rotating outboards have the exact same number of gears: 3
One driveshaft gear,
one 'driven' gear used for forward,
one 'driven' gear used for reverse.

The main difference between them,
is which of the two driven gears the shift shaft engages,
when the remote control is moved.

And the bearings supporting the gears are different;
whichever gear is used for forward,
must withstand, continuously, the full horsepower of the engine,
while the gear for reverse carries only a very small amount of load,
for a very short time.

Some Suzuki engines are designed such that either driven gear
can handle the full continuous load of forward motion.
If you have the same engine, which both turn the same direction (crank) and you put the motors and gear, what causes the screws to spin in opposite directions?

Forgive my ignorance, but an extra gear is what gives us counter rotating screws on my tug so I assumed the theory was the same.

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