How to choose the right propeller for your boat

Choosing the right propeller for your boat

Choosing the right propeller for your boat can be a bit hit and miss.

Considerations include boat design, weight distribution, running characteristics (RPM) and how and where it will be used.

When choosing the right propeller for your boat you’ll also want to consider the material used (aluminium or stainless), number of blades and pitch.

A lower pitch allows you to build up RPM quickly which is good for big boats with a heavy load.

But there will be less forward travel with each revolution so not good for top speed.

A higher pitch is slower to build up RPM resulting in lower pulling power and acceleration but a greater top speed once the vessel winds up.

You’ll also need to know how to read the prop. Meaning – how to identify the size, diameter and pitch of a propeller.

Most props have a series of numbers on the side or inside the hub.

A three blade prop, 18.75 inches in diameter with a 19 inch pitch will have the numbers 3 X 18.75 X 19.



Numbers are printed on the side of your prop tell you the number of blades, diameter and pitch of your prop.

To determine the size of your boat propeller look for the numbers inside the hub

If they are not printed on the side of the prop, look for the numbers inside the hub of the propeller to determine diameter and pitch.

Stainless or aluminium

Typically creek boats run aluminium props as the material is softer. This will result in less damage to the engine if you hit something. However they’re more flexible which results in lower performance.

Stainless props are more expensive due to higher performance. However better used for offshore vessels because hitting a hard object with a stainless prop can result in damage to the shaft.

Aluminium props are cheaper and can be “sacrificed” when hitting something. In other words, the prop, instead of your motor, is damaged.

Because I’ve been operating for years at Hinchinbrook and know my way around. Plus I prefer to fish open water for big barra, I run a stainless prop on my boat.

You can check out some of our fishing action videos > here <

Number of blades?

For choosing the right propeller for your boat you may also want to consider the number of blades.

Three blades is most popular and typically more efficient.

Four blades have better grip and better for cats because they create more lift in the transom.

Choosing the right propeller for you boat requires trial and error.

Marine dealers can assist in choice of prop for your boat as they encounter these issue regularly.

Often, your dealer can supply two or three props for testing when you buy a new motor for a small fee.

This is because boat design, load and the running characteristics of your vessel all play a part.

Watch our video as we chat to marine mechanic Matt Solis from Barneys’s Marine Hervey Bay for some tips and considerations when choosing the right propeller for your boat.




Choose the right prop to get better performance and fuel economy

One way to tell is to run at WOT (wide open throttle) or flat out!

Try a higher pitch prop if your RPM is too high.

However if it's too low and you'll need to try a prop of lower pitch.

Contact your local dealer or consult your manual for optimum RPM ranges for your engine.

As you can see, choosing the right propeller for you boat is not an exact science!



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About The Author

Ryan Moody

Ryan Moody started his fishing career on the reef boats before catching bucket list marlin for the likes of champion heavy tackle angler Johnno Johnson, INXS and the King of Sweden. Branching out in the late 80's to guided barramundi fishing, Ryan has made a name for himself as a Big Barramundi specialist and to date has put clients onto over 2000 metre plus barra. That is over 2 kilometres of metre plus barra! With attitudes changing from 'keep all you can' towards catch and release, Ryan has decided to share his extensive knowledge and hopefully inspire people of all ages to get out from behind the computer screen/TV and into the fishing outdoors lifestyle he has spent his life perfecting.

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