Prop Advantage/Disadvantage

[Ron Moss]

In the interest of GPH is it more or less adventageous to run a four blade prop over a three?

[ondarvr]

For an accurate answer you need to supply a great deal more information.

It will depend on the Boat, load, motor, HP, lower unit and what you plan to do with it.

[BrassMonkey]

Originally Posted by ondarvr

For an accurate answer you need to supply a great deal more information.

It will depend on the Boat, load, motor, HP, lower unit and what you plan to do with it.

A Correct four blade will run better #s than a Correct 3 blade in most cases.
Props are a Black Art!!
What is the perfect prop for our boats?Thats the Million $ Question.

[tomictime]

in god we trust, all others bring data. In general however a 3 blade will out perform a 4 blade for MPG/GPH. The 4 blade will have a better hole shot and perform better in rough water - for scientific reasons, mostly related to blade loading. The extra blade does not come free tho, it results in higher drag.

here are a couple of things to DO to take the "black art" out of it:

Buy props from experts, who almost always offer exchange till you get it "right"..Maybe not the lowest price, but will save you a bunch in the long-run

run the curves and let facts speak for themselves. here is the data on flatwater for my 3 blade. From a MPG point of view it is 20% better than the best 4-blade I could find. I went thru 4 of them on the boat. The 4-blade is a much better rough water prop tho.