# 4 blade vs 3 blade prop



## tom_in_orl (Dec 9, 2006)

I didn't think that they existed but I stumbled upon a 4 blade prop for my motor. Right now I am running 10 3/8 x 12 pitch 3 blade. I am planning on moving up to at least a 13 pitch. The 4 blade is a 10 x 11. Should I be looking for the same pitch in the 4 blade or should I go down?


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## Guest (Jan 8, 2007)

Get a same pitch with 4 blades prop but u will lose alittle bit top speed but u will able to raise it higher and run shallow. 4bp had a better grab with water.

4 blades propeller= a lot quicker hole shot, better thrust power in crusing speed, and running shallower in higher engine position. U can tow your kids sking no plm.

3 blades propeller= better performance, more top speed, and less cupping in high engine position for shallow water.

I had a 4 blades prop on my keylargo, I lost 3 mph and a whole a lot better hole shot and run real shallow but it's worth it for me but I broke it. Back to normal 3 blades prop.


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## tom_in_orl (Dec 9, 2006)

I did some more looking and found a 13 pitch but its a composite material


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## orlgheenoer (Dec 10, 2006)

I would get the 4 blade since you have a 30hp.

Its not like your gonna lose speed.


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## Tom_C (Dec 10, 2006)

> I didn't think that they existed but I stumbled upon a 4 blade prop for my motor. Right now I am running 10 3/8 x 12 pitch 3 blade. I am planning on moving up to at least a 13 pitch. The 4 blade is a 10 x 11. Should I be looking for the same pitch in the 4 blade or should I go down?



You need to know your RPMs first :


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## Ron_W. (Dec 14, 2006)

If you plan to jack the motor and run shallow don't get to exited about the 4-blade. Most small outboard 4-blades are shaped for high thrust, low speed applications like sailboats and pontoon boats. This type of blade design is not suited for jack plate running at a high motor hiegth. I needed a spare prop for my Noe's 25hp Merc so I bought an aluminium 4-blade from I-boats. I pushed the Noe fine but even with a couple inches of jack it cavitated badly and was virtualy useless. The prop had some factory cup and more prop work could have made it marginaly functional. 

Test #2
I was able to try a Power Tech 4-blade stainless prop courtesy of Thresher. Again it was disapointing, while the preformance was better than the aluminum it was still far below the 3-blade stainless Vengance with custom cup work that I normaly run. The Power Tech has a small factory cup and is better designed for speed and it worked well on Threshers Gladesman but on the Noe with a Bob's jackplate and 6" set back it did not preform. I'm sure with some time and money it could have been tuned to work well but I did not see $400.+- being worth the risk.
I believe someone on the Gheenoe forum custom set up a power tech 4-blade and got it working well but still runs a three blade most of the time if I recall there post accurately.

As for your prop pitch I would guess a 4-blade at 12p and a 3-blade at 13p would have you running in the mid 5000rpm range.


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## Guest (Jan 8, 2007)

Forget about the 4 blades prop. Get a 3 blades prop 10x14 pitch. 2 more inch pitch will lost 400 rpm but more top speed.

4 blades prop is best suited for gladesman 18 due to flatbottom hull and will run shallower than gheenoe classic.

Gheenoe classic is best for 3 blades propeller and a high speed boat due to kinda like a vee hull.

I need to get my 40hp back so I can run mid-40 mph on light weight gheenoe lol.


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## orlgheenoer (Dec 10, 2006)

The gheenoe runs shallower then the gladesmen [smiley=thumbsup.gif]


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## kicker (Dec 16, 2006)

This is a pretty interesting topic. When I bought my boat it had a 3-blade stainless prop, I also have the stock 3 blade aluminum but I havent tried it. Ive been thinking about looking into a 4-blade prop as I get cavitation in turns (im sure has alot to do with the shape of the hull too) and thought it would help once I get a JP and raise the motor up. Alot of friends that I bass fish with, occasionaly get together for a day and everyone tries each others props.

Would anybody on here be interested in something like that?

o yea, im running a 04 25hp merc.


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## tom_in_orl (Dec 9, 2006)

Check out this thread http://www.microskiff.com/msforum/YaBB.pl?num=1167177502

A bunch of us will be there but now that I think about it.....It would be a few mile run to get out of the Manatee zone.


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