Stainless Steel vs Aluminum Prop: What's The Difference?

Sales of new powerboats in the US in 2020 were at their highest levels in over a decade. Boat sales are likely to remain at historic levels in 2021 as Americans continue seeking ways to safely enjoy the outdoors.

Whether you're new to boating or you've been enjoying your boat for years, you'll eventually need a new propeller. How do you find the right one?

When you're looking for a prop for an inboard, outboard, sterndrive, or ski and wake boat, you have a lot of choices. Should you choose a stainless steel or aluminum prop? What other factors should you consider?

Find out the differences between stainless steel and aluminum propellers. You'll be able to buy your next prop with confidence.

Advantages of a Stainless Steel Propeller

Stainless steel propellers are very durable and last longer. The blades are thinner, which reduces drag. You have more design choices, so you can find the prop that works best with a particular type of boat.

The blades won't flex at high speeds. You get better performance and better fuel economy. This gives you an increased range per tank of gas.

If you want to improve the performance of your boat, upgrading to a stainless steel propeller is a cost-effective way to do it. You get better handling, acceleration, and speed.

Stainless steel is a popular choice for saltwater. This is partly because saltwater boats have higher horsepower.

Stainless steel props work well in abrasive environments like sandy, shallow water. If you run frequently in shallow water, you have a higher chance of hitting the bottom. The additional strength of a stainless steel prop is probably worth the price.

Many people think that a stainless steel propeller is more likely to damage your lower unit if you hit something underwater. Testing has shown that this usually isn't true, however.

Disadvantages of a Stainless Steel Propeller

The main downside of stainless steel props is the price. Stainless steel is a more expensive material than aluminum. A stainless steel prop can be twice as much or more than the price of an aluminum prop. Repairing stainless steel is more expensive.

Stainless steel props weigh twice as much as aluminum, so you need a more powerful engine. If your outboard is 125HP or less, stainless steel probably isn't the best option.

When you need a stainless steel prop, you may have to wait for the stock to come in. Stainless steel props are often back-ordered for weeks.

Stainless steel props are more attractive to thieves because they have a better resale value. You'll need to be sure to secure your boat.

Benefits of an Aluminum Prop

Aluminum propellers are affordable. They give you good performance under most conditions. Many pleasure boats come from the factory with an aluminum propeller.

For light fishing and general use, a standard aluminum prop will be fine.

Aluminum is lighter than stainless steel. If you hit something, the prop fails before any damage occurs to the shaft or seals. Repairing an aluminum prop is easy if it gets damaged.

You may find that buying a new propeller is cheaper than repairing the old one, though. You can find a replacement easily because most dealers have many aluminum props in stock.

Aluminum is a good choice for a spare propeller because of its affordability.

Disadvantages of an Aluminum Prop

Aluminum propellers can flex under high RPMs. This will cause a drop in pitch, which reduces performance. You also get lower fuel economy.

The blades are thicker than stainless steel. They create more drag, which lowers your top speed. However, if you don't spend a lot of time running at full throttle, you probably won't notice a slight reduction in your top speed.

Aluminum propellers don't work well in sandy conditions. They're also not ideal for motors with higher horsepower or for high-performance motors.

Although you can repair aluminum props more easily, they get damaged more easily too. In addition, once the prop shop has heated the aluminum to hammer it back into shape, the propeller isn't as strong as it was originally.

Other Prop Features to Consider

Metal is an important factor in choosing the best boat propeller. You have several other features to consider, though. Looking at construction and style elements help you maximize the performance you get from your prop.

Diameter and Pitch

To get the most out of your boat, you need a propeller that's the right size.

Diameter and pitch identify the size of the prop. The diameter is two times the distance from the center of the hub to the tip of the blade. Pitch is the theoretical distance the propeller will move forward through the water with one revolution. Both measurements are given in inches.

Larger boats need larger blades and/or larger diameter.

A higher horsepower motor lets the prop power higher RPMs, which will allow for a higher pitch. If you want more top speed, you can move up to the next pitch. The propeller doesn't add horsepower, though, so your engine has to have the power to get the recommended RPMs.

3-Blade vs 4-Blade Propeller

You can find propellers with different numbers of blades, but 3- and 4-blade props are the most common.

A 3-blade prop is less expensive and better at top speed. You get better fuel economy at wide-open throttle.

You have a larger selection of diameters and pitches for 3-blade props. However, they give you less control in the water.

A 4-blade prop gives you better acceleration. It has more surface area than a 3-blade prop, so the boat gets on plane quicker. You maintain the plane at a lower RPM, so you get better fuel economy.

4-blade propellers give you better control. They're also good for low-speed pulling. If your boat has added weight like live wells and water tanks, the traction from a 4-blade prop will help you get the boat on plane.


The hub is a shock absorber between the prop blades and the shaft. The two main types of hubs are pressed or interchangeable.

A pressed hub is semi-permanent. The prop shop fixes it in position with a high-pressure press. The prop installer inserts an interchangeable hub.

If you run frequently in shallow water where you have a higher chance of hitting the bottom, you should consider an interchangeable hub. The insert should break before the propeller itself or the prop shaft.

Buying the Right Propeller

To find the best boat propeller for sale, you need the best supplier. Deep Blue Yacht Supply has been providing superior products, technical expertise, and customer service for more than 15 years. We'll get you the right product on time from one of our many warehouses throughout the US.

Check out our large inventory of boat props. Whether you want a stainless steel or aluminum prop, you're sure to find what you're looking for.