The 7 Best Boat Propellers for 2021
Quicksilver Black Diamond
Rhink Marine Three Blade Aluminum Prop
Ian Fortey Updated on August 19, 2021.by
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Buying a boat propeller seems like it should be an easy task. But there are actually so many factors you need to take into consideration. It can leave you scratching your head. Let’s cut through the confusion and take a look at the best boat propellers on the market today.
Choosing the Best Boat Propellers
You need to make sure you have the right propeller on your boat or things will work poorly. Boat propellers have the diameter and pitch inscribed in the hub. It may also be along the side of the propeller. Check your old prop for these numbers before buying a new one. If the numbers aren’t present for some reason, you can figure it out the old-fashioned way.
Diameter can be measured by hand. Measure from the center of your hub to the edge of the blade. That’s your radius. Double it and you have prop diameter.
We’ll get into propeller pitch later in detail. For now, if you’re not sure, know that pitch is measured in inches. An 18 inch pitch propeller would move 18 inches in the water with one revolution. More pitch equals more speed but slower acceleration. What you need depends on your particular boat and engine. Check with your engine’s manual or a specialist to find out the best pitch if you don’t know.
Most props are either three blades or four blade props. There is a difference in performance.
Three Blade Props: You will get a higher top speed out of a three blade propeller. They are typically less expensive as well. They take longer to get on plane, though. Most recreational boats have three blades.
Four Blade Props: These are better for tougher conditions as opposed to top end speed. Four blades work well in rough water. They will also be more fuel efficient. You will lose some RPM, though. You plane quicker with a 4 blade propeller. They tend to be more expensive overall.
What is Pitch?
The word pitch has been used frequently here to describe props. Pitch refers to the distance the propeller travels during one revolution. This is affected by the radius of the propeller.
There are two kinds of pitch for propellers. Constant pitch is the same at all points during the rotation. The pitch remains the same from the leading edge of the propeller to the trailing edge of the blade. But there is also progressive pitch. Progressive pitch starts lower at the leading edge. It then goes higher at the trailing edge. This number is calculated as an average across the whole propeller. Progressive pitch is typically just used for boats that want increased speed.
As far as most boaters need to know, pitch is like a gear ratio. You want your pitch to work with your wide open throttle or WOT. Your engine’s manual will tell you what your WOT is.
If you have a lower pitch than you need, your engine may go over the WOT RPMs. That’s not a good thing. It means you’re going to be straining your engine. This can cause engine damage or the engine may set up a rev limiter.
If you have more pitch than you need, the opposite happens. You’re going to lose RPMs. That’s going to make your engine struggle. So there are times when a low pitch propeller is what you want depending on boat speed. The right prop depends on what you do with your boat.
Pitch is measured in inches. It’s not set in stone, but if you move up or down two inches, your WOT will change by around 400 RPM. Keep that in mind when choosing the pitch for your prop.
You likely want a lower pitch if you’re moving heavy loads frequently. If you’re just cruising around, low pitch three blade props are great. If you want to up the ante a bit and go water skiing, then you can stick with low pitch and try four blades.
Stainless Steel Propellers vs Aluminum or Plastic
Most boat propellers are going to be one of these three materials. Aluminum props tend to be the most common. They are lighter and cheaper and can do a great job. However, stainless is definitely stronger. Stainless is also able to have thinner blades. If you want a top quality boat propeller, stainless steel is probably what you want. Most boats come with aluminum propellers. Large boats like yachts and small fishing boats alike.
Plastic props are more common on small boats. They require less power and the prop will do less work. The propeller blade on a plastic prop is going to be flimsy, as you might expect. Heavier boats can’t use these. They’ll have more drag than the prop can handle.
For optimum performance, stainless steel props are best. The boat’s performance will reflect this. However, you may see increased fuel efficiency with a lighter aluminum prop. Much of it depends on the type of boat and engine you have.
Basically, a stainless steel prop is going to last longer than the others. Up to five times longer, in fact. It can stand up to more abuse. You’ll be less likely to need to replace it as soon as another type.
Is a Stainless Steel Prop Always the Best Choice?
Many people think a stainless steel propeller is always the best choice. But for a lighter and smaller boat, that may not always be the case. As you saw, many aluminum props are extremely high quality. Aluminum props can deliver better hole shot and increase speed. They give great fuel economy and have a wide pitch range. Whether you want a lower pitch or something higher, an aluminum prop could work fine.
The other big consideration is price. Aluminum props are cheaper. That price difference can be very significant.
The Bottom Line
The biggest concern you need to keep in mind is sizing. So many boat owners have messed up and bought the wrong size prop. Don’t feel too bad if it happens to you. The numbers can look confusing. Just make sure you check and double check before you buy.
Installation should be easy for any prop. When in doubt, check online or ask a pro. Stay safe and have fun.