Pontoon Boat & Deck Boat Forum

I have a 22' Avalon with a 115FS Yamaha. I am considering a stainless prop and keeping the aluminum one for a spare. I am not necessarily looking for a performance gain but if it happened I won't complain. I figure having a spare on board is a good thing and the stainless seems it would be more durable.

I need some advice on what brand of prop is good and what if any differences I will see over the aluminum one.

I am not sure of the diameter or pitch of my current prop but it came with the motor. Currently WOT is about 5600 rpm and I get 23KTs GPS with 3 or 4 people on board. We usually cruise at about 3800rpm and 13kts.

Thanks

MAP wrote:I have a 22' Avalon with a 115FS Yamaha. I am considering a stainless prop and keeping the aluminum one for a spare. I am not necessarily looking for a performance gain but if it happened I won't complain. I figure having a spare on board is a good thing and the stainless seems it would be more durable.

I need some advice on what brand of prop is good and what if any differences I will see over the aluminum one.

I am not sure of the diameter or pitch of my current prop but it came with the motor. Currently WOT is about 5600 rpm and I get 23KTs GPS with 3 or 4 people on board. We usually cruise at about 3800rpm and 13kts.

Thanks

i run a 13p stainless on the 60 evinrude and ive noticed better performance and faster blowout recovery at high trim or sharp turns. I have a aluminum spare of the same pitch and there is a big difference.

I tried to go to a stainless prop and it didn't work out for me. I have a 90 hp and bought the same exact size and pitch as my aluminum one. It was however a different brand. My Rpm's went for 5,400 which was perfect to 4,500 , way to low. So be cautious on what you get as they aren't cheap. I ended up selling my to a member on here dahogman and fortunately it worked out for him.

Best advice would be if you could find a marina nearby that may work with you and allow you to try a couple different ones out.

Thinking 13 to 14p might be right. Agree with heat, need to get a dealer or prop shop to work with you finding the right prop. There is one downside, they won't bend if you hit an obstruction like the alum will.
doc

"There is one downside, they won't bend if you hit an obstruction like the alum will."

That to me is the upside, I don't want my props to bend if I hit something. Most things you hit won't affect a SS prop but will bend the Hell out of a alum. I have run SS props for over 30 years and have never had one hurt or hurt anything else on the motor. I have hit a lot of stumps and stuff with no problems. Some of my boats would do over 50 m.p.h. and I have hit things at those speeds and not a problem. I hate alum props they are usless once you hit something.

jimrs wrote:"There is one downside, they won't bend if you hit an obstruction like the alum will."

That to me is the upside, I don't want my props to bend if I hit something. Most things you hit won't affect a SS prop but will bend the Hell out of a alum. I have run SS props for over 30 years and have never had one hurt or hurt anything else on the motor. I have hit a lot of stumps and stuff with no problems. Some of my boats would do over 50 m.p.h. and I have hit things at those speeds and not a problem. I hate alum props they are usless once you hit something.

I agree completely....bottom line if ya hit something so hard that you'll break/bend a SS prop... chances are good that you're going to damage the lower unit anyway. One brush w/a sandy bottom and it's time to recondition the aluminum which is a pain and gets expensive quick....Alum's are great to keep in the boat as a spare.
One thing you may notice with SS props is more prop chatter or growling at slow idle....this is normal.

You’ll need to know some info about your motor before you do the switch:

1. What is your engine’s max RPM? (yours is probably 6000 rpm if your rev limiter is letting you get to 5600 now)
2. What is your current prop pitch?

As a general rule you’ll gain 200 RPM at wot on your engine for every inch of pitch you go down. If you’re running a pitch of 13 now and are getting 5600 rpm at wot you’ll get 5800 rpm if you drop the pitch to 12. Diameter also plays a role in that as you go down in diameter you’ll also increase you rpms at wot. However, you are going from an aluminum to a SS prop which changes things a bit. You see, an aluminum prop will “flatten out” when placed under load. Thus, an aluminum prop that has a pitch of 13 will flatten out to say a 12.5 under wot. SS props on the other hand don’t flatten at all under load so you may find yourself going down a little more in pitch to reach your desired rpm at wot. You want to shoot for your motor to run at its max rpm or a little lower with a light load on board.
If you do the switch I’d like to know what your results are in that I’m thinking about switching to SS myself. Good luck

slingshot wrote:You’ll need to know some info about your motor before you do the switch:

1. What is your engine’s max RPM? (yours is probably 6000 rpm if your rev limiter is letting you get to 5600 now)
2. What is your current prop pitch?

As a general rule you’ll gain 200 RPM at wot on your engine for every inch of pitch you go down. If you’re running a pitch of 13 now and are getting 5600 rpm at wot you’ll get 5800 rpm if you drop the pitch to 12. Diameter also plays a role in that as you go down in diameter you’ll also increase you rpms at wot. However, you are going from an aluminum to a SS prop which changes things a bit. You see, an aluminum prop will “flatten out” when placed under load. Thus, an aluminum prop that has a pitch of 13 will flatten out to say a 12.5 under wot. SS props on the other hand don’t flatten at all under load so you may find yourself going down a little more in pitch to reach your desired rpm at wot. You want to shoot for your motor to run at its max rpm or a little lower with a light load on board.
If you do the switch I’d like to know what your results are in that I’m thinking about switching to SS myself. Good luck

Good info.

Another thing...
My i/o is running a mercCruiser Alpha drive.
It has that plastic 'Flo-Torq II' hub between the prop n the lower unit drive shaft.
If i hit anything that hard, the plastic hub should break first, saving my lower unit.

That feature would make me feel better if i was running an SS prop.
Although im running an AL prop cause its Cheap!

Saves more money for BEER!!