Testing 3 Blade vs 4 Blade Propellers What’s the Difference Between 3 and 4 Blade Outboard Props

any amount of your support is very appreciated, Thank You... Prop Clear!!!

[curtis-thebicentennialist]

Back in my boat racing days, we'd take several props to the lake and test them. The 4 blade is the correct type for your boat but I'd take 3 or 4 props at 2" pitch intervals in order to get the rpms close to 6k. Dropping 1 or 2" pitch might get your speed up a little as well as maintain mpg and on-plane time. A good dealer will let you try several props and allow you to purchase the one that best suits your application.

[mohamhead]

I was always told to drop 2 pitches down when going from a 3 blade to a 4. That would bring your max engine rpm up too. Plus stronger acceleration as a bonus.

[pauln]

Had a good read of the comments, know nothing about the difference between using a 3 or 4 blade prop. So thanks for taking the time to do this. EIRE.

[junkyardspecial]

Why would anyone thumb down, honest review?Nice vid captain...

[intrademan]

Good job Bro, may bien! It helped me decide to switch to 4-blade props as top speed is NOT a priority but fuel savings and better handling is!

[MikeWMiami]

Another thought on pitch. If a lesser pitch is unavailable, check with a quality prop shop like FJ Prop Miami to see it they can make an adjustment. Back in the day I was with Pitman Photo Offshore Racing and for a while Mercury supplies our engines so they could test engine mods on our boat. There prop guys, Dennis Cavanaugh, actually in Fond Du Lac would adjust our props to fit exactly what Mercury wanted. It’s definitely possible and probably not that expensive to have done. Sorry fir the long comment. Great video by the way.

[terryg]

1st class comparison test!!! I just changed over to a four blade on my boat and it really improved the perfromance.

[michaelh]

Where I am, we usually don't have many days of slick, calm water. I have a 24ft with twin 150s. I went from 3 blade to 4 blade. What a difference! When fighting swells or strong current, I have a lot more torque to push through.

I try not to run more than 2/3 throttle as it makes a big difference in fuel consumption with 2 strokes.

[itscorky]

Changing from a 3 blade to a 4, I definitely had more bottom end torque (Have the 4.3 inboard). Great for water skiing. The good news, going to a 4 blade helped me with my WOT. I no longer have to worry about blowing the engine since WOT hit exactly 200 RPM below my redline at a perfect pitch. Top end speed was the same at 55 mph. Could go faster with the 3 blade, it would just blow the motor. Dropped the RPM down dramatically helping fuel economy at cruising speeds at around 30 mph. Happy I made this change!

[besimtitiz]

I can't wait to watch your next trip to the Bahamas with the New 4 Blade Propeller Capt. Be Safe & Take Care!!!

[brianfencker]

Great test Cap. When I test props, I always test it with full fuel and a load that corresponds to 2 person. I usually pick the prop that reaches the mid range between low/high WOT rpm limit f.ex. 5.500 rpm within the limit of 5.000-6.000 WOT rpm. In your case, I would pick 1" lower pitch so your WOT rpm could reach close to 5.500 rpm. I really looking forward to your next trip to the Bahamas and see your fuel usage. Navigate safe.

[djdavidj]

I just replaced the prop on a fresh water runabout. The only prop in stock was a 4 blade. I decided to go with 4 blades because a lot of time is spent manuvering around other boats in the marina and also docking to a houseboat. I found that the four blade prop gave me way more control at lower RPMs. Even reverse was noticeably improved.

[brianblizzard]

I concur with what most have said about too much pitch on that prop. Your engine is not at its HP potential at 5100 rpms at a very light load. You may see the reverse of what you want when you are loaded for the Bahamas. I would take your prop and numbers to a reputable prop shop and see what they say. In many instances, they can change pitch a size or two with your prop. Keep us posted capt!

[maxxgraphix]

I had a Mercury Vengence 14 x 19 and my max speed was 45 on a good day. Most of the time 43mph. It would also loose speed in turns when pulling a tube. I tried a 15.5 x 17 3 blade and it caused vibrations. I switched to an Apollo 14.25 x 19 and the boat felt sluggish getting to top speed. The Apollo has a lot of cupping. Hole shot was ok, but after that took forever to hit 40. I got a Solas HR4 14 x 17 4 blade. Hole shot was fantastic, on plane 3 seconds and got to 40mph much quicker. Top speed was about 45mph at 4700 rpm. My boat is heavy being a 99 Sea Ray Sundeck 240 with a 5.0. Also pulling tubes, no problem for the 4 blade. It doesn't slow down in a turn. Just set it to the speed you want and leave it. In smooth water I bet it will hit 47mph and a light load. But like others said, you are over propped at 5100rpm. You could try a better blade like the Merc Revolution.

[michaelrutledge]

Of course a boat running at a higher rpm will consume more fuel. You need to get the engine running at the same rpm’s in order to determine data, unless your motor cant turn a 4-blade prop at 5700rpm. All in all, a good effort to compare the two though. Keep at it, Cap.

[andrewfyakim]

Hi Capt... this is great information. I think a lot of us would benefit by changing props. I cannot change my prop from on the boat; I'd need to be in the water or on the trailer. It's easier for me to be in the water... I see below there are some who recommend a lower pitch; it would be nice to have access to multiple props to get try them all out. But, buying a large variety of props would be expensive. I've also been thinking about raising my engine about an inch as the anti-cavitation plate is under water when I'm running on plane. It measures out to be correct when out of the water, but runs a bit bow high unless I use the trim Thank you for the hard work it took to put this video together!...

[frankmmiii]

Before even watching the video I can tell you I used to fly model planes with a couple guys who were engineers. They would experiment with one bladed props and a counter weight. They told me that they were more efficient than the two bladed props and had success with it. I can see that the fewer the blades the less resistance you will have making your "screw" more efficient.

[edkonvang]

nice comparison! i never had 4 blades on my boat but i always thought 4 blade would be better. Now, after watched your video. the 4 blade is off my list. thanks for the video!

[Nauticalcraze]

I think it would be cool to see videos anywhere overnighters in Florida. Catch clean and cook Miami, Keys, Tampa just anywhere .... you have great content all the time. Keep up the great work Captain!!

[violetsydney]

3-Blade Propellers

Higher top speed: 3-blade propellers generally have a higher top speed than 4-blade propellers.
Better acceleration: 3-blade propellers also have better acceleration than 4-blade propellers.
Less drag: 3-blade propellers have less drag than 4-blade propellers, which can lead to improved fuel efficiency.
More efficient at higher speeds: 3-blade propellers are more efficient at higher speeds than 4-blade propellers.
4-Blade Propellers

Better handling: 4-blade propellers provide better handling and stability, especially at low speeds.
More grip in the water: 4-blade propellers have more grip in the water than 3-blade propellers, which can be beneficial for boats that are used for towing or carrying heavy loads.
More efficient at lower speeds: 4-blade propellers are more efficient at lower speeds than 3-blade propellers.