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S20 w/70HP Yamaha

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Thunderduck

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Propeller options for my rig ??? Currently turning a 3 blade aluminum 13.75 x 13 @ 5,200 rpms (about 20 mph). Does anyone offer a stainless steel wheel for my 70HP Yamaha ??? I'm thinking SS 14 x 11 pitch. Thanks in advance.
 
Stainless props are usually not recommended for HP under 150 ( performance vs cost ) . You can purchase one .but it is not likely you would see any improvement in performance .
According to the Prop Recommendation Chart that Bennington supplied to my dealer ,your recommended size is 13.8X13 .That is right there with what you are looking for .
 
Thanks Jack. The boat lives in Homosassa, Florida (shallow river w/ hard bottom). The limestone bottom just destroys Aluminum propellers.
 
If you do purchase a Stainless ,look into a Flo Torq hub . It could save your drive shaft . This one is a Mercury ,they are also made for Yamaha .
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Thunderduck said:
Thanks Jack. The boat lives in Homosassa, Florida (shallow river w/ hard bottom). The limestone bottom just destroys Aluminum propellers.
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If you run a SS prop and hit that (and it’s already destroying aluminum props), you will destroy your drive shaft. I wouldn’t do a SS for this reason in those conditons. Better and cheaper to fix aluminum props. If you are still going to give it a try, consider the flo torq hub above that Jack shared.
 
Thanks for the tip on the Flo Torq. The salesman recommended an aluminum prop to protect the engine but I want SS for my 150 HP Yamaha. Will now have the best of both worlds.
 
SS props are much heavier than aluminum so there is a point of diminishing returns vis a vis rotating weight. I personally run shallow and a stainless prop is much better when it comes to dealing with constant nicks from bottom contact, but I also have a big 250 V6.

If you are STRIKING hard bottom then an aluminum could save your lower unit gears from damage, but you really need to avoid running in those areas first and foremost. Any decent hub will potentially spin or break in the bore on a hard strike but that's really just a lottery ticket and no guarantee. Stick to known channels, have a good depth finder, read the water, go slow in unknown areas and trim up if needed. Your LU is not long for this world if you keep hitting stuff!
 
Yamaha makes the Talon (SS) in the 4.25 gearcase size
6EK or 6N6 series

I wouldn't go down to 11", I think a 12" might get you very close to 6000 RPM @ WOT
 
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