Stainless Steel vs Aluminum Outboards


Material choices for outboard and sterndrive propellers are Aluminum and Stainless.

How does an aluminum propeller differ from a stainless steel propeller?

Aluminum Propeller

Aluminum boat propellers are relatively inexpensive, easy to repair, and under normal conditions can last for many years. They’re great for small and mid-sized boats. 

Aluminum boat propellers are lightweight at about 1/3 the weight of stainless and will flex to help prevent damage to your outboard motor if it strikes something.  

Aluminum boat props are available for nearly any outboard or sterndrive motor you may have. Leisurely boaters will be well suited with an aluminum propeller.

Typically black, sometimes off-white or gray, aluminum boat propellers will come in a painted finish. Aluminum is easier and less expensive to repair than stainless. However, due to the price of new aluminum propellers excessive damage is often better off replaced. When repaired in our facility, they will come out of the paint booth glossy black.

Stainless Propeller

Stainless steel boat propeller is more expensive, but much stronger and more durable than aluminum. If you are looking for better performance than can be provided by aluminum propellers, such as ultimate top speed or better acceleration, a stainless steel boat propeller may be a good option. This is due in small part to the material itself (less material flex), and largely to the designs and options available in stainless that are not available in aluminum.

Expanded options offered in stainless steel that you won’t often find in aluminum include counter-rotating sets, a large range of blade designs and sizes, and vents. For information about ventilation see our previous blog post.

Stainless steel boat propellers can come in a polished or satin finish and occasionally painted. Although stainless is more expensive to repair than aluminum, the price gap from repair to replacement usually makes it well worth repair. When repaired in our facility, stainless boat props go through a two-tumbler polishing process. We will re-paint a previously painted stainless as the material used will need protection from rusting.

Who benefits most from Stainless Steel?

Higher horsepower motors and performance boat owners especially take note of performance differences between aluminum and stainless steel boat props. Boats rated for speeds over 50mph will benefit from going to stainless steel. Stainless would also be recommended for boating in saltwater.

Tacoma Propeller always suggests carrying a spare propeller on board so you never lose a day of fishing or a weekend of fun. Aluminum is a cost-effective solution as a spare, even if your running prop is stainless steel.