Originally Posted by TRBenj
Kyle, in theory, the fewer the blades, the more efficient the prop. Ive found the 3-blades Ive run to be a bit faster than the 4's. I think that the large blade surface area found on the modern CNC props largely levels the playing field between 3 and 4-blades, at least for applications with relatively low loads (skiing and footing). If youre show skiing or running a wakeboat with 2k lbs of ballast, I hear the 4's still do better for the big loads, especially out of the hole.
Tim, it's been a while since I have inspected one up close, but the large blade surface area thing is not necessarily a function of CNC machined props, but rather an Acme design feature. When I compared two similarly sized props, one an Acme and the other an OJ XMP, the Acme had more surface area per blade. This was several years ago. But as far as I know, OJ has not varied the design of their 3 blade props from a blade area perspective. You can see the measurements I took and a side by side picture of the two props in the link below. Both companies make very good props. But, as I'm sure you know, they are different and perform differently.
Acme vs. OJ XMP 13x12 3 Blade Prop Comparison
From the article:
The Acme has an approximate blade size of 8 3/16” across the blade (vertical
in the picture) and 5 1/8” from hub to the edge of the blade. At first glance,
the surface area of the blades appears larger on the Acme. From my
measurements, it appears that the Acme has about 1” on the OJ on the vertical
blade measurement. From hub to edge, they are about the same.
The OJ has an approximate blade size of 7 3/16” across the blade and 5 1/8”
from hub to the edge of the blade.
Previous: 1993 Prostar 205
Red 1998 Closed Bow Ski Boat, PCM GT40, 310 hp, Standard Gear Reduction, Acme 4 blade, Perfect Pass SG/Zbox.
Tyler Ski Club
Be kind. Have fun.