Hiya 9-R, Sorry for my late response.
As paul has said, my Suzuki had an ally prop. It was severely dinked so I looked into a replacement.
Peter B (Paul B's father) had a stainless prop on his outboard, and advised me about the slight speed increase, so I dug deep to find the answer
Basically from what I remember, The ally props, although a good all rounder and cheaper than the stainless are somewhat susceptible to flex when under speed/load.
The stainless steel props wont flex like the ally, they give a cleaner cut into the water and a far better grip on exit. A standard sized swap to stainless in my opinion is a worthy upgrade, you'll immediately notice a drop in vibration and you should see an increase in top end speed.
I went up a pitch as my WOT (Wide Open Throttle) reading allowed the drop in rpm whilst staying in the manufactures advised spec.
The advisory figures are 1" further forward per inch increase in propeller pitch per revolution. So in theory, Two props of the same diameter.... a prop with a pitch of 10 will advance your boat one inch further per prop revolution apposed to a prop with a pitch of nine.
You will loose approx. 200rpm per pitch increase or gain 200rpm at WOT opposite if going down a pitch
A lower pitch will give you a faster hole shot, but a loss of top end speed. A higher pitch will give you a better top end speed, but a slower hole shot...
Can you equal the loss of holeshot by replacing the ally prop with a stainless...? TBH, I'd need to try that one out.
I found the Honwave, as all inflatables go sky high if you hole shot, totally impractical in my opinion...
So that's when the Hydrofoil comes into play.
- Stingray Junior
To offer my experiences,
I bought a Solas Saturn Stainless 3x9.25x10. I'd suggest it gave me a 3-4 knots increase over the old standard 3x9.25x9 ally prop. However, paired up with the Stingray Junior, I've lost some of that top end but got a much more satisfying boat. It's up on the plane in no time, at much lower speeds, has deffo helped with the mpg, and no more highly annoying skyward bow under holeshot.
Take a look at the
"2 Go To Play" thread and see the difference in how the two Honwaves with the same outboards ride completely differently. Yes my 3.8ie is slightly longer and wider, but the difference is dramatic in slight chop with the Stingray hydrofoil. A much more pleasant ride, no pointing to the sky, nowhere near as much bounce, on a whole.... A lot better !
Here's how it looks...
- Stingray Junior And Solas Stainless Prop
- Solas Saturn 3x9.25x10
Figures & Speed....
Honwave (Floppy Floor) T38ie weighs in at 48kg
Suzuki DF15 @ 44KG
Lightweight Me @ 85KG + Whatever heavy gear I'm wearing
Fuel aboard, Anchor, etc... maybe 20KG
Top ever speed registered...
23.4 knots via Navionics GPS, Somewhere between Lismore to Benderloch (West Coast of Scotland)
- Navionics app on iOS
Hope that helps, and I haven't sent you to sleep
Martin
I'm not looking for general answers but specifics from experience. Not from what others have said or assumed but strictly from experiences from anyone who has tried and tested between Aluminum vs Stainless Steel. Not looking at impact, repair feasibility or wear resistance, only performance differences.
have a pint of Tetley... 
