3 or 4 Blade Propellers for SMALL Boats?

Join host Ryan Wood as he explores how boat performance changes with 3 vs 4 blade propellers. Conventional wisdom is 3 blade props are better for top end speed, and 4 blade props are better for acceleration and hole shot (time to get on plane). See if this holds true (or matters at all) for a small boat.

Boat: Carolina Skiff JV 15
Motor: 25 hp Yamaha 4 stroke
3 Blade Propeller: OEM Yamaha 9 7/8 x 11 1/4 f (Aluminum)
4 Blade Propeller: Solas Amita 10-2/5 x 11 (Aluminum)

It is recommended to go down slightly in pitch when switching from a 3 to 4 blade prop. Boat propellers arte identified by their diameter (1st number) and the pitch (2nd number).

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Thanks for watching RWood Outdoors!

[RobertPeniston]

Let's not get too critical. He took the time and energy to do the video. I enjoyed it.

[robertyouens]

Nice simple demonstration with the expected results. You want to see 5700 to 6000 rpms at full throttle to assure you are in the ECU optimal mapping curve. With a heavy boat weight, to low motor hp, as you are running, what you gain with a 4 blade is reduced slippage. When properly pitched you will improve hole shot and improve fuel effeciency (up to 10%) with a 4 blade due to reduced slippage. You will typically lose about 1 to 2 mph at top end (due to increased blade surface area), but gain about 10% in fuel effeciency if operated at a moderated planning speed (not wide open). The lighter the boat and the higher the speed the less improvement you will see with a 4 blade... that is why you see racing boats running 2 and 3 blade props (because slippage is not as much of an issue).

[ronniehenson]

When you guys go to a 4 bladed prop, drop down 1 size in pitch and keep the engine in the correct recommended RPM range and you can have the best of both worlds hole shot and top speed or at lease the same speed you had before the swap.

[jobhoogeboom]

I have an little 12 foot aluminum v-bottom aluminum boat with an 2010 20hp Yamaha 4 stroke. I recently installed a 4 blade propellor of an Honda 20hp 4 stroke. The boat definitely gets on plane much quicker. And it can even get on plane with 4 persons now.

[fiveowaf]

I've tried 3 and 4 blade propellers on my 14 foot Polarkraft with a 20hp Mercury. I have really found little difference in top speed, or lift onto the plane, but slightly prefer the 4 blade, I definitely notice more bite when for example shifting to reverse and then back to forward. One of the problems in comparing is variations in design, some recommend dropping the pitch going to a 4 blade, with other props the pitch seems it can be kept the same on a 4 blade. It's really hard to get a definitive answer since even a slight change in the wind strength can affect my top speed by a couple of mph, so by the time you change the prop. you cannot guarantee the exact same conditions. All I can conclude is that while they provide very similar performance, the 4 blade does work better a little better for me and my boat, but again that could be just the fact the 4 blade suits the setup and gives the perfect rpm on the top end whereas the 3 blade tends to over rev in one pitch and bog a little in the higher pitch. There are just so many variables.

[dustin]

That boat needs a 90's two stroke 50hp. I can't believe any dealer would even sell a boat like that with a 25hp motor.

[rogerjackson]

throw a 75 on it with 25 stickers...thats what we do up here

[Rlip]

I had a similar boat with a 70hp Yamaha 2005 2 stroke great combo! Good on fuel too

[Crazyreseller]

To put it simply, your boat is underpowered.

[isajakwa]

thanks for spending a lot of time making this very usefull video.

[kameranspahn]

Just get a 50 man it would fit that boat perfectly even if it’s not “rated” for a 50 you can always strengthen up the transom if needed but you be able to hit 25 mph a lot quicker and easier than what your working with. Good and informative video man🍻

[davidking]

the test in the future you may want to consider is getting out the chart for you motor to see at what rpm your torque first starts to peak and run the test at that rpm range. The 4 prop will increase the efficiency for a given fuel burn by pushing more water. High rpm runs over a period time is a good way to burn up /pit your props when you start air rating the water at high rpm spin

[Drunken_Hamster]

Not gonna lie, I think you should get twice as much motor, lol.

[sargepent]

What's more important is the pitch. I recently changed my prop pitch and while I lost little holes hot speed, it had a higher cruse speed with lower rpm which equals fuel savings. Plus I can troll slightly faster with the same engine speed. Best is to have your local marine service provider supply you with the best prop for your specific boat

[jerrygray]

Did you really say "hammer down" with a 25hp motor?

[edwardabrahamiii]

Yup i miss my grandpa being around i use to take boat rides with em on his little 16ft lund boat with a 25 yamaha that 16ft lund was light he had trim and tilt on his 25 yamaha it would fly over the shallows even if it only got a top speed of 27mph

[SouthFlaDiver]

Drop the pitch on the 4 and you'll gain back top end and better shot

[roughym]

If the 4 blade prop has the same pitch as your 3 blade prop then you're not going to achieve the manufacturers recommended rpm at WOT. In which case you may damage the gear case of your motor over time. What pitch is the 3 and 4 blade props?

[danielhaglund]

I like 4-blades as well. That hydrofoil will cost you top end speed. As many have said you are over pitched. If you want to run that 4-blade you could try to remove the hydrofoil and raise the engine a bit. The 4-blade will grip better so you can run the motor higher and you already have smart tabs so the hydrofoil may be overkill.

[Silentroller]

Raise the motor up like 3” on the transom, you’ll be able to run a higher pitch prop.