playing with props.

[Boatsb]

So I figured I might gain a bit of cruise speed going from 3 to 4 blades.

1966 41c.
8v53's and a 7.5kw genny
250 to 270 gals fuel
Full water
Lots of spare parts and tools (500 lbs) plenty of personal items.
4 full grown men.
3/4 inch transom wedge no trim tabs.


Started with a pair of 21 x 24 4 blades with #4 cup.

I also have a pair of 2r x 23 3 blades with #3 cup.

2200 rpm and 16.2 kts.

It seems slow at idle but still runs 4.2 kts at 650 rpm.

Finishing up some cooling system maintenance then I'll probably do a full range of runs and documentation.

Any suggestions on what props to try?

By the way the 4 blades are just so smooth

[Boatsb]

2200 rpm

[SKYCHENEY]

Good lookin' wake.

[Boatsb]

That's at 16. I have hit 21 before. Just figured I'd be easy on the pumps. Impellers and cooling systems need work. That's for this weekend.

She rides so well on plane.

[Boatsb]

Rogers 34 at 23 kts.

[dsharp]

The 3 blade prop is supposed to be the most efficient. But, every 41 wth 8-53's that I ever saw had 22x22 or 22x24 Michigan Dyna-Quads.I don't remember what those engines are supposed to turn but, I thought it was 2400 rpm

[Boatsb]

The 3 blade prop is supposed to be the most efficient. But, every 41 wth 8-53's that I ever saw had 22x22 or 22x24 Michigan Dyna-Quads.I don't remember what those engines are supposed to turn but, I thought it was 2400 rpm

2750 to 280p I believe.

I'm not sure but I think it was original with 24 x 24 4 blades.

[dsharp]

I had forgotten that they spun them that high. That engine always made me nervous on a shake down run. It seemed like you were lying beside a screaming bomb. What does the number on the cup designate? Putting a cup in the blade wasn't very common in this part of the world. Usually it would take about 50 rpm off the WOT

[Finalee]

That looks faster than 16.

[bobk]

The 3 blade prop is supposed to be the most efficient. But, every 41 wth 8-53's that I ever saw had 22x22 or 22x24 Michigan Dyna-Quads.I don't remember what those engines are supposed to turn but, I thought it was 2400 rpm

Everything I've read or heard says fewer blades = more efficiency. A one bladed prop is theoretically the most efficient, but the vibration is hell. Seriously, a good prop shop will provide the best advice.

Bobk