In most cases, by simply making a direct conversion to stainless in the same size as your aluminum prop, you will notice an improvement in both acceleration and top speed. The reason for this is very simple, but frequently misunderstood. Stainless is seven times stronger than aluminum. Propellers don’t have to be that much stronger so manufacturers can make them thinner and still be two or three times as strong. Thinner props cut through the water easier and this of course translates to better performance.
Stainless propellers generally cost a couple of hundred dollars more than an aluminum or composite propeller.
There are two situations where we don’t recommend stainless over aluminum or composite: smaller outboards in pleasure applications, (because the prop can be stronger than the gear case parts) and for very occasional boaters who are happy with the existing performance of their boat.