Prop advice needed alloy to stainless

[Jonny H]

Im changing my prop over to a stainless which is a 13p.
Having spoken to two companies in the week one say I need to stay the same pitch but having spoken to another they say I need to drop down to a 12p if going to a stainless.
I know that the props are different makes one being a Solas but does anyone know which is right ?
Ive had chopper props before and bought stainless props for other boats ive had in the past, when running the engine higher on the transom but for a normal application would I need to change pitch just swapping to a stainless ?

[Nos4r2]

I'd drop an inch.

[Turbodiesel]

Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.

[BogMonster]

Originally Posted by Turbodiesel

Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.

That was the advice I got from Oakley Marine when I discussed props with them a couple of years ago, he said because the SS blades are stiffer and thus usually thinner on a stainless prop you can increase the pitch by an inch with no problems.

I didn't in the end, because I figured the risk of rotavating a rocky beach meant it was better to stick with a cheaper alli one so I just bent the prop not something more expensive.

[codprawn]

Originally Posted by Turbodiesel

Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.

Do they though? I have stainless but is there REALLY that much difference???

[spartacus]

Do they though? I have stainless but is there REALLY that much difference???

As far as I'm aware this would make a difference on a large engine, however the difference would be negligible on smaller outboards, probably anything under 50hp. Nice bit of bling though.

[jyasaki]

Stiffer blades, more weight. True, thinner blades, but also usually a more aggressive blade shape. Usually adds up to 100 to 200 rpm loss or so if diameter remains the same, from what I've seen.

If you could only try a single prop, I would say dropping an inch would be your best bet.

I would ask if you could try one and swap it out if it's wrong. If the supplier won't go for that, you might try different suppliers. Paying a bit more for that would be cheaper than getting stuck with the wrong prop.

jky