better to be at the low end or top end of RPM?

[brodmann]

I've always preferred an aluminum prop. They're much lighter, so they're able to spin faster and since they have a slight bit of flex to them, I think it's better on the motor when accelerating quickly. I'm strictly a salt water guy, so there's little chance of stumps and logs and stuff for me to hit, so Aluminum is my "go-to". But, there is much more "slip" with aluminum I've noticed. For example, I went from a 17 pitch SS to a 17 pitch aluminum and picked up 1 MPH increase at WOT, but and increase of 5,000 RPM's. So, according to my calculations, the SS prop had right at 5% slip, where the aluminum prop had 13% slip. That's on a 2 stroke 115 Yamaha. The aluminum prop planes off much more quickly though. I've never paid much attention to brand names on props though. Never thought there was much difference between one brand and another.

 

[QBhoy]

I've always preferred an aluminum prop. They're much lighter, so they're able to spin faster and since they have a slight bit of flex to them, I think it's better on the motor when accelerating quickly. I'm strictly a salt water guy, so there's little chance of stumps and logs and stuff for me to hit, so Aluminum is my "go-to". But, there is much more "slip" with aluminum I've noticed. For example, I went from a 17 pitch SS to a 17 pitch aluminum and picked up 1 MPH increase at WOT, but and increase of 5,000 RPM's. So, according to my calculations, the SS prop had right at 5% slip, where the aluminum prop had 13% slip. That's on a 2 stroke 115 Yamaha. The aluminum prop planes off much more quickly though. I've never paid much attention to brand names on props though. Never thought there was much difference between one brand and another.

I’d say that the standard k series ally prop on a Yamaha (excellent engine) like that…is a great prop to be fair. They run better than any of the cheaper stainless props about.
But a good merc expensive stainless is hard to beat. Even a good old laser 2 is an exceptional thing for some boats

 

[QBhoy]

I've always heard, when it comes to props, weight doesn't matter. Once it's spinning that's probably true but I've wondered, for example, if putting a heavy 4 blade stainless on an alpha 2 would cause more stress on the shift mechanisms especially lower shift cable coming in and out of gear.

To be honest…it maybe can..when it comes to bigger blade heavy props like that. But I’d also add that there are excellent damping hub kits available now that will lessen such things.
But on that note. Some props are hugely heavier than others. The difference between an enertia 3 blade x7 and a tempest or rev 4 is very noticeable in weight.

 

[Texasmark]

I've always heard, when it comes to props, weight doesn't matter. Once it's spinning that's probably true but I've wondered, for example, if putting a heavy 4 blade stainless on an alpha 2 would cause more stress on the shift mechanisms especially lower shift cable coming in and out of gear.

My take, on pressed in rubber hubs, is that the shock is mitigated by the rubber interface. I had one plastic/brass replaceable insert hub prop and it had no room to give. It didn't stay long on my engine.