3 vs 4 blade props, (a little info)

[Bifflefan]

So I had (still have) a 3 blade 14.5x19p alum prop. It was fresh out of the prop shop. Installed it and all in all it works fine, nothing to write home about.
Last weekend I swapped it out for a new 15x18p 4 blade and WOW what a difference.
Both props are alum and both made by Michigan Wheel.
Aside from the new vs old hub style they are direct replacements for each other. (Per Michigan Wheel)

Here is a list of what I found:
Similarities:
Both move the boat through the water.

Differences:
4 blade:
Has way less torque steer,
Better hole shot,
Better top speed,
Better boat control, at all speeds,
No porposing at all with trim tabs flat, (that is an issue with the 3 blade)
Pulled up a skier with little effort, 3 blade was a struggle.

I ran both on the same lake, same day and same boat loads with the same activities.

IMHO the 4 blade is hands down the better choice in my apples to apples comparision.

I will not be using any 3 blade again unless its an emergency.

 

[steelespike]

Re: 3 vs 4 blade props, (a little info)

In general a 4 blade will usually out perform a 3 in low to mid range.especially hole shot staying on plane at reduced throttle,more responsive, resists venting,usually
smoother and responds better around the dock.Allows higher outboard mount.Where they usually fall down is top speed. They don't all do all these things better it depends on the 3 blade style.I think your amazing difference is partly from a 3 blade
that while freshly repaired may have been a little blow par from age or design.
Do you have any rpm and speed figures for both props?

 

[Bifflefan]

Re: 3 vs 4 blade props, (a little info)

I didnt write anything down, having to much fun at the time...
While I may be off on the top speed, with a full load of people and pulling a 4 person loaded tube, i can hit about 38 MPH @ 3500 RPM. this is as fast as i turn the old girl. this is the same speed i can do by my self with the 3 blade, and the same RPM. maybe a 100 or so RPM difference.

I didnt think of the prop being old and causing some lose in performance.

I still love the 4 blade, and as for balls out blowing my hair off, that is what my racecars are for.....