To counter-rotate ...or not

[SuperNova]

I have a boat with twin Alpha 1's. Both drives rotate in the same direction and I was thinking about changing one to counter rotating. I have looked into it and know that you have to get the lower leg, and I know exactly what is involved in the change (pretty simple, really). My question is this...I read on a certain outdrive site that someone recommended NOT going to a counter rotating outdrive due to the additional complexity of the lower half tends to increase it's failure rate. Any truth to this? I am thinking that the advantages of counter-rotating outdrives may outweigh any reliability issues. Thanks for your thoughts.
--
Stan

 

[45Auto]

Re: To counter-rotate ...or not

Do you currently have a noticeable torque problem steering the boat? What advantage do you expect to gain going to counter-rotating?

 

[SuperNova]

Re: To counter-rotate ...or not

Better low speed maneuverability, straighter backing and better control when backing and turning. Plus, my understanding is the efficiency of a twin setup is better when the props rotate opposite of each other. High speed is currently not a problem as far as torque steer...but when I am backing down into a slip, it is difficult to get the stern to swing to ..port? I think.

 

[bigblocksarefun]

Re: To counter-rotate ...or not

Its definitely safer having the counter rotating maneuverability. Not having it is just like having a single screw.

 

[TilliamWe]

Re: To counter-rotate ...or not

I thought only the Alpha 1 Gen 2s could be run in reverse?

 

[SuperNova]

Re: To counter-rotate ...or not

I thought only the Alpha 1 Gen 2s could be run in reverse?

You don't actually run it in reverse. There is a lower half for the outdrive that is designed to be counter-rotating. All you do is reverse the pivot-point of your cable on the helm controls and install a lower half designed correctly. The engine and upper half of the outdrive still rotate standard. All the reversing is done in the lower half gearset. You can do it without getting the counter-rotating lower...but they tell me it won't live long.
--
Stan

 

[BAYLINER185]

Re: To counter-rotate ...or not

Yea I think what he is saying is the drive actually uses reverse gear then as forward and forward as reverse.

I dotn know why that woulnd work as my machanic had a lower unit taken apart the other day and to me it looks like both those gears are the same any way. One is just in front of the other.

What would be so bad about that if its just a change in cable so that when in forward gear it actually puts the drive in reverse?

All you need to do it swap the prop to a counter rotating prop then right?

 

[JCF350]

Re: To counter-rotate ...or not

I dotn know why that woulnd work as my machanic had a lower unit taken apart the other day and to me it looks like both those gears are the same any way. One is just in front of the other.

What would be so bad about that if its just a change in cable so that when in forward gear it actually puts the drive in reverse?

The bearing setup needs to be different as the the normal reverse gear bearings are not strong enough for extended operation.

 

[Bondo]

Re: To counter-rotate ...or not

What would be so bad about that if its just a change in cable so that when in forward gear it actually puts the drive in reverse?

Ayuh,....

It Don't Work that way,.........It Ain't that Simple.....

 

[JCF350]

Re: To counter-rotate ...or not

Ayuh,....

It Don't Work that way,.........It Ain't that Simple.....

Then which way do it work (since they do it with a lower unit swap)?

 

[Bondo]

Re: To counter-rotate ...or not

Then which way do it work (since they do it with a lower unit swap)?

Sorry,.. forgot to include the Quote.....It's Fixed now...

 

[TilliamWe]

Re: To counter-rotate ...or not

See, Bondo is vaguely referencing what I thought. It's not the gears it's the thrust against the actual case. And I didn't think there was anything you could do to an Alpha 1 to solve it. Not even changing the lower unit. I thought that was one reason the Alpha 1 Gen 2 was introduced and is almost completely different than the Alpha 1.
Please elaborate Bond-o. Is it as simple as a complete lower unit change, or can an Alpha 1 not be made reverse rotation at all?

 

[Bondo]

Re: To counter-rotate ...or not

Ayuh,.....

On both drives,... The Lower unit's Guts,+ Bearings are Totally Different......

Unfortunately,... I'm having a Problem C&Ping the graphics from the adobe file to Here....
If you want to See the Difference,.... Open a pdf. of the Alpha,+ go to the counter-rotating lower unit.....

 

[SuperNova]

Re: To counter-rotate ...or not

They have counter-rotating lowers for the Alpha 1. Internally they are very different due to the thrust loads. For example, the normal alpha 1 lower has..say.. 10 parts to it, whereas the counter-rotating version has 30 parts. After that it is as simple as a cable swap. Actually you can just do the cable swap (and prop of course) and you'll have a counter-rotating setup....but they say the lower won't last very long.

 

[JCF350]

Re: To counter-rotate ...or not

pics!

Left pic is counter rotating. Alpha one

 

[TilliamWe]

Re: To counter-rotate ...or not

Thanks!

 

[SuperNova]

Re: To counter-rotate ...or not

Great!!!......Now can we get back to the original question???

 

[bomar76]

Re: To counter-rotate ...or not

The next conumdrum will be "In or Out?"

 

[JCF350]

Re: To counter-rotate ...or not

Great!!!......Now can we get back to the original question???

Murphy says yes just because you gots more moving parts, howthemsoever.
They list any specifics? All?, 1 in 10, 1 in 100?, horsepower limitations?, time? Anecdotal statement?

 

[SuperNova]

Re: To counter-rotate ...or not

Murphy says yes just because you gots more moving parts, howthemsoever.
They list any specifics? All?, 1 in 10, 1 in 100?, horsepower limitations?, time? Anecdotal statement?

No, just the guy who actually sells them and works on them said if a twin with C/R came in with outdrive problems, he'd go to the C/R unit first because it failed first 90% of the time. He sells the units and recommended not switching to C/R...that says something. But I would still like a little confirmation from anybody who has a little firsthand experience whether this has any merit or not and also whether the additional risk (if true) is worth the potential gains.