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Counter-Rotator-Prop Question

S

shiggs

Well-known member
I just came into possession of a counter-rotator with a boat I just finished putting back together. It has a 496 8.1L engine with a 2-1 lower pulley.

I am pondering about switching the counter-rotator upper assembly into my other boat that has a 572 with a 2.3-1 lower pulley.

Does anybody have any suggestions on the prop setup for a 572 and a counter-rotator? Keep in mind that with a 2.3 reduction the front prop is a 3.5 reduction to the engine and the rear prop is a 2.3-1.

Right now with the 2-1 and the 8.1L, the front prop is a 3-1 to the engine and the rear at 2-1, I am running a sensenich 80" 3 blade wide (K) pitched at the last mark (3) and a 78" 3 blade narrow (H) pitched at (2). With the counter-rotator instructions dictating that most of the load be put on the front prop--I think I am about max on this set-up at least following the counter-rotator instructions. I think i could have possibly run 3-superwides S-blades on the front and just less pitch on the narrow on the rear.

With that in mind and a reduction that is steeper I think my 572 might run 4 superwides and 4 narrows. Diamondback says they run the narrows behind the superwides because when they ran wides behind them, they got some cavitation. Any suggestions??
 
Faron,

Since you are the first to respond, any ideas on the set-up for my other boat??

Did you to talk to the owner??
 
On the 572 counter rotation I would suggest a 4 blade master blaster Whirl Wind and then the 3 Blade Narrow Sensenich. I know it seems wierd to run two different brands but we love it.
 
4 Blade Master Blaster and 3 Blade Narrow Sensenich

gold.JPG
 
They both ran awesome, I think they are both 2.3 but I'm not 100%

If I were building my dream boat I think I would only want the 572 with a 4 blade 84" Master Blaster. I know that it saves $10,000. But in your case since you already have it I would use it! You can get the Master Blaster Prop in a 2:1 or 2.3 version.
 
Shiggs,

A conservative count would be about four or five of us C.R. guys on the site here :cry: Build it and they will come.....

I had the C.R. added to my existing long belt drive so I know firsthand the benefits of it. I love it :D

You gotta check out the movie The Aviator to find our C.R.'s inventor, (kind of). Some here think the Nazi's invented it!

Basketcase
 
I'd like to know more about the effects of running the same number of blades on both props vs. different number

Wonder which is quieter?
 
Basket,

Did you add the counter-R to your existing set-up. How much better does it perform than before?

What engine/prop combo do you have--is it a 2-1 or a 2.3-1?

I am really considering putting it on my 572--It is already a beast, but you can always have more. Since I have got it on this new boat I thought I might just trade the upper units.

I hope the four or five others that you mentioned read this and respond. I am curious to the prop combo for that 572.

I have to admit I thought it would be quieter than what it is (It is quieter but not what I expected)--at least from everything I have read and what is advertised.
 
Ditto , to what Farron said ! . 4 blade Master Blaster and 3 blade narrow Sensenich ,Great combo
I personally run a 84" 3 blade super wide and a 80" three blade narrow Sensenich w/ a 2.3/1 belt drive ( pics in album ).... fantastic push , good cruise , and quiet .
With this combo my motor still has power to spare , so when mother nature turns the ice back into water , I'll be doing some experimenting and trying out two new combo's
#1 4 blade Super wide w/ a 3 blade narrow
#2 3 blade Super wide w/ a 3 blade medium
Will be interesting to see what the outcome is !?!

In talking with guys that have run a 3 x 3 w/ the same paddle width , they say that they have experienced a chop / cavitation or backwash , if you will , between the two blade sets .

Several boats around here are running paddles w/ a multi blade warpdrive behind them and they work good , but I know the BIG paddle and narrow blade works better :wink:
 
Alaska,

Please post your results of the different combo's when you get around to doing that experiment.

sh
 
You may want to give the airboat prop guy at Sensenich a call. His name and phone number is findable on this forum. They have run every test imaginable for counter rotators. My set up called for an 80 x 78 3 x 3 mainly because I'm at 5,000 feet and lose up to 20% of the horsepower of my engine.
 
cavitation happened in wide blades in front and back. I haven't heard about any cavitation with the super wides. If u go to the 3.5 and the 2.3. I would say u would need a 4 blade super wide and a 3 blade wide blade sensenich props of course!! I guess u can say I'm partial to sensenich because I make them? :D
 
Shiggs,

Sorry so long for the delay in the reply...the grandkids bout' killed me yesterday :bigsmurf:

14 X 8 hull
425 HP/454 Chebby
2.3 Franklin long belt drive
L80K 3 bl with R80H 3 blade, (Sensenich wide and narrow blades)

Yes, the C.R. assembly was added to the boat after the long belt drive was already there. I carry a lot of crap on my boat for whatever I might need type situations. This makes my rig very heavy so I needed the C.R. for the extra ummph!
It was the difference between night and day as far as push, being quieter and fuel economy!

Hope this helps,

Basketcase
 
BASKET WROTE: It was the difference between night and day as far as push, being quieter and fuel economy!

I can vouch for that because I did a lot of pushin on that baot while he was learnin to turn around on the beach, LMAO gotcha basket love ya'll anyways
 
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