Stainless prop

[HD]

I have never purchased a stainless steel prop and I am entertaining the idea. What pitch? How do you determine which one? Are there different brands?

Pro's and Con's?

[The General]

Well one con is you hit a rock and instead of the prop bending you wreck internal parts.

[Wyofish]

Well one con is you hit a rock and instead of the prop bending you wreck internal parts.

Tearing up a lower unit at Stoke's Bay would not be fun. My boat came with a stainless, but I just use it as a spare.

[Lee Borgersen]

I've had the same S/S prop on my smaller lund since 1976 and I love it.  I did have to have it re-hubbed once. Every time I buy a new motor I've kept that prop on it. I also feel I've picked up a slight speed benefit with the S/S prop.

[deadeye]

Please note these are NOT my words

How To Choose Stainless vs. Aluminum

Many boats are factory-equipped with aluminum propellers. Aluminum propellers are relatively inexpensive and suitable for general purpose use. Stainless steel propellers are more expensive, but are far stronger and more durable than aluminum.
If you are looking to improve the performance of your boat, upgrading to a stainless steel propeller is the most cost-effective way to get better handling, acceleration or top speed out of your boat.
Will a stainless steel propeller damage my lower unit in the event of an underwater impact? Mercury engineers, conducting underwater impact testing, found no substantial difference in the amount of torque transferred to the propeller shaft between an aluminum and stainless steel propeller. Mercury’s Flo-Torq II hub system is designed to give way during an underwater impact – protecting the outboard and still providing you the ability to idle home safely.

Here are some general rules
The question is, what is your max rpm currently with normal cargo load. What is your engine's max operating range?

If it's 5,000-5,500 rpm, and you are currently seeing 5300 rpm max, you'd want a 18" uncupped or a 16" cupped prop. If it's only 5100 rpm, you'd want a 17" uncupped or 15" cupped prop.

If it's 5,000-5,500 rpm and you are currently seeing 5700 max rpm, you'd want a 20" uncupped or an 18" cupped prop. If it's way up to 5900 rpm, you'd want a 21" uncupped or a 19" cupped prop.