Port shaft noise. Let me know your thoughts regarding it.

I hit some rocks a couple years ago. The port side had the most mangled prop and the engine was killed and wouldn't restart.(starter relay failed, I don't understand why). I motored on stbd side back to the marina, 10hrs mostly in the dark.

Later I had to go about a mile to a lift to inspect damage, change props. I fired up the port side hoping it was at least usable to help control the boat going into the lift. I didn't exceed 1,000rpm, I was surprised by a 'singing' sound and thought maybe I'd damaged that transmission.

There's been talk of fine tuning the prop edge to prevent singing. My port prop was mangled, blades literally torn, some pieces missing, and folded over...certainly not equivalent to just an edge needing a fine tuning.

We put the new props on, much to my relief the singing was gone. I had never heard of props 'singing' at that time. I thought perhaps some unusual, erratic vibrations or thrust was being transmitted up the shaft to the trans causing something inside to 'sing'.

Bad prop-boat was 'singing', new prop-singing stopped. I don't really know where it came from, it was a first for me.
 
After about 50hrs if use this season it is still the same noise at the same rpms. One more thing I will check in the fall is to slide the shaft back and inspect the area of the shaft that rides in the cutlass bearing to see if there is something such as a burr that could be creating the noise. Others than that it but be prop sing.
 
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One thing you could try is to have a diver run an emory cloth over the leading edges of the singing prop. That edge should be rounded. The trailing edge should have a sharp edge. Make sure he knows the difference between leading and trailing. Oftentimes a small change in the way the water flows over the prop can change or eliminate the harmonic sounds
 
An interesting read and i appear to have the same thing happening on my port side. Albeit my noise is not quite as loud and it is only there at idle speed. As soon as i bump the throttles its gone. I just bought this 420 DB and of course on survey no one noticed the sound. I noticed it on its maiden 150 mile voyage home as i was pulling out of the marina at mile 1. No vibrations or sounds otherwise and the boat ran great the entire time. But that sound is there at idle. My boat was ran onto rocks last year. A reputable shop replaced all of the running gear (struts, bearings, shafts, props, etc). Now i'm wondering if either the port is out of alignment, or if that new port prop is just singing...
Curious, did you ever figure out what your noise was coming from?
 
An interesting read and i appear to have the same thing happening on my port side. Albeit my noise is not quite as loud and it is only there at idle speed. As soon as i bump the throttles its gone. I just bought this 420 DB and of course on survey no one noticed the sound. I noticed it on its maiden 150 mile voyage home as i was pulling out of the marina at mile 1. No vibrations or sounds otherwise and the boat ran great the entire time. But that sound is there at idle. My boat was ran onto rocks last year. A reputable shop replaced all of the running gear (struts, bearings, shafts, props, etc). Now i'm wondering if either the port is out of alignment, or if that new port prop is just singing...
Curious, did you ever figure out what your noise was coming from?

I have not figured out where it is coming from. I have a little over 120hrs on it this season and the noise has not changed at all. This winter I am going to pull the props and have the prop shop redo the anti-sing edges. I am also going to unbolt the shaft from the tranny and slide it back out of the strut a ft or so and check to see if there is something on the shaft itself that is making the noise such as a burr or something of that nature. Other than that we are stumped. I am not concerned with it being a problem but I would like it to get resolved. Hopefully one of the above procedures will be the cure.
 
Did you ever find out what the whining noise was? My port trani is whining when I put it in gear... either forward or reverse.
 
Did you ever find out what the whining noise was? My port trani is whining when I put it in gear... either forward or reverse.
It ended up being prop sing. I had the prop shop put anti-sing edges on the props and the noise went away.
 

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