Tips for Choosing Boat Propellers

Getting the right propeller for your boat helps determine how well your boat is going to perform out on the water, and there are many factors that go into choosing the right one. 

With so many different props available, picking the right one can seem a bit overwhelming at first. Here are some tips to help you determine which propeller types work best for you.

Material: Aluminum vs Stainless Steel Propellers

The first decision to make when it comes to choosing propellers is whether you want an aluminum or stainless steel propeller.

Aluminum

Pros: Less expensive and lighter in weight

Cons: Weaker and suffer from performance drop-offs. 

Stainless Steel

Pros: Stronger and maintain performance

Cons: Heavier and more expensive

NOTE: Propellers made of other materials also exist, but we’re focusing solely on aluminum and stainless steel props. 

As a general rule, if your outboard is 125HP or less, you should stick with aluminum props. This is because the additional weight of a stainless steel prop and its extra bite in the water both work against the outboard to reduce its effectiveness.

If you run in shallow waters frequently, there’s a higher chance your prop will strike the bottom, in which case the additional strength of a stainless steel prop is worth the additional price. With prop strikes being an issue, consider choosing a propeller with a replaceable insert that’s designed to break if the prop hits something. By being the weakest link in the chain, the insert should break before the propeller itself or the prop shaft, which would be far more expensive to replace. If you mainly run your boat in deeper water, then a pressed hub should do just fine.

Because aluminum isn’t as strong as stainless steel, aluminum propeller blades are usually thicker to stop them from flexing and bending at high RPM. Thicker blades cause more drag in the water, which reduces a boat’s top speed. If you don’t spend much time running at wide-open throttle, you won’t really notice a small loss of top-end speed.

The big downside to stainless steel propellers is the price. A stainless steel prop is typically double the price or higher of an identical-spec aluminum prop. For example, a 10x14 aluminum Solas Amita 3 can go for about $100 less than a 10x14 stainless steel Solas New Saturn.

If you’re ready to pay extra, a stainless steel prop will likely last you longer. As for performance, stainless steel appears to be better than aluminum, but out on the water it’s unlikely you’ll notice much of a difference between them. 

Blade Count: 3-Blade vs 4-Blade Propeller

Your next choice is whether to go with a 3-blade propeller or a 4-blade propeller.

3-Blade Propellers

Pros: Less expensive, better for top speed, don’t affect RPM

Cons: Offer less control in the water 

4-Blade Propellers

Pros: Better for acceleration and provide more control in the water

Cons: Lower the motor’s RPM

NOTE: Propellers with more and less blades also exist, but we’re focusing solely on 3-blade and 4-blade propellers. 

A 4th blade increases the prop’s surface area, which gives it more bite in the water. As a result, 4-blade props have a much better hole shot and acceleration than 3-blade propellers, so they can get a boat up on plane quicker and maintain it at a lower RPM, which improves fuel economy. 

The increase in surface area makes 4-blade props better at running offshore, where conditions are more variable. Plus, the additional bite provides better control of the boat, keeping it heading in the right direction at the correct speed.

The bite provided by a 4-blade prop is also better for low-speed pulling. If you’ve added a lot of weight to your boat — livewells, water tanks, tower, etc. — the extra traction from a 4-blade propeller could prove invaluable in giving your boat enough “oompf” to get it out of the water and up on plane again.

The added traction of a 4-blade prop creates additional resistance and drag in the water, which works against the outboard and reduces its RPM. If absolute top speed is your thing, a 3-blade propeller might be the better option. A 3-blade propeller is also more fuel efficient at WOT, because it generates less drag in the water. Three-blade props also offer a wider range of diameters and pitches. One less blade also means less material to manufacture, so 3-blades are usually cheaper than 4-blade props.

For general boating, a 3-blade prop will serve you well. However, if you run in rougher waters or carry a lot of weight on your boat, then a 4-blade propeller could improve your boat’s performance. Props are also easy to switch out, so consider investing in both a 3-blade and a 4-blade prop, and using them as needed. 

Solas Propeller Brand Recommendation 

A quality brand product performs better, lasts longer and is more cost-effective over time. One of the most popular propeller brands is Solas, which offers a vast range of 3-blade and 4-blade stainless steel and aluminum props in every diameter and pitch. 

Every Solas prop is designed, tested and manufactured in-house, so you’re getting a precision-engineered piece of equipment that will stand the test of time. Special casting processes allow for stronger, thinner blades that provide optimum performance in the water.

Whether you choose Solas or another brand of propeller, Boats.net has a massive variety of quality boat propellers at great prices. If you have any questions about our propellers or anything else, please contact us and we’ll be happy to help you out.