New Prop & Prop Harmonics

[janus2]

Hey All,
I have an E35 MKIII Hull#211 M25-21hp Universal.
Right now I get an odd howling noise at 2000 RPM and above.
I am told it's a prop issue. (Prop Harmonics)

Anyone familiar with this?

The current prop is a 3 blade 15x11RH.
Another interesting note is that the motor is rated for approx 3000 rpm but at present we can only get 2400-2500 rpm out of her. Could this be a result of what I believe to be an oversized prop? I'm sure that the boat originally came with a 2 blade prop, but don't know the size.

I am wondering if anyone knows what the original prop was for my boat.
Also if anyone has any recommendations as to a better fixed prop for my boat, I would be grateful.

Thanks, Steve Wallace, Campbell River, BC.

 

[evm]

Thats a lot of prop

Hey All,
I have an E35 MKIII Hull#211 M25-21hp Universal.
Right now I get an odd howling noise at 2000 RPM and above.
I am told it's a prop issue. (Prop Harmonics)

Anyone familiar with this?

The current prop is a 3 blade 15x11RH.
Another interesting note is that the motor is rated for approx 3000 rpm but at present we can only get 2400-2500 rpm out of her. Could this be a result of what I believe to be an oversized prop? I'm sure that the boat originally came with a 2 blade prop, but don't know the size.

I am wondering if anyone knows what the original prop was for my boat.
Also if anyone has any recommendations as to a better fixed prop for my boat, I would be grateful.

Thanks, Steve Wallace, Campbell River, BC.

Not knowing much about it I would say that your are over proped. My E39 has the same size on a 30 HP yanmar 3hmf which appears to be a good match for this 20000 pound boat.

Regards, Ethan

 

[RON CARTER]

Prop noise

Steve. We had much same problem with Azgard, 35-3 hull 127 1983 over many years starting with p.o. We even did a complete engine change to the new 25 xpb model with a few more hp and noise persisted.. Problem prop was rh 16 x10 Federal Michigan 3 blade and noise was at 1400 to 2000 rpm with a clean hull and would vary to 1700 to 2300 with growth on bottom. I believe problem is not enuff space between prop blades and hull. We loaded all our specs into prop firm computer and they came out with 14 x 9 which has been perfect for us... no noise, better speed at various rpm, etc Prop is "Campbell Sailer" 3 blade made in Nanaimo, sold in Vancouver by www.westbynorth.com Norm Ross, price was 475.00 but that was 2005 so expect another 100 now Talk to them Ron