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.