shaft shrill/wine

[Bill Poot]

Just took position of a Pearson 33-2 with a Yanmar 18 horse diesel. On moving the boat to home port, engine ran well all the way for 10 hours. On throttling back, at about 800 to 1000rpm, a shrill noise was herd from, what we believe, is the shaft area. I could move the throttle up and down through the shrill area. Any experience or insight????

Thanks,

Bill

 

[kenn]

Does the boat have a stuffing box? Was it re-packed, or tightened recently? If so, it might be a bit too tight, and has dried up. You can try loosening it a little, or maybe dribble some water on the shaft when it is turning to see if that stops it.

Just a guess...

 

[Steve Dion]

I have heard that the prop can create this sound. Nothing wrong, but just a frequency that resonates from the prop tips.

 

[Stu Jackson]

Three things to check, two already covered: stuffing box, prop blades or cutlass bearing. Dem's da only movin' things down dere mon!

 

[Witzend]

The installation of graphite packing seems to be more susceptible to this sort of sound since the impression is that the packing is almost dripping less. Back the nut off to drip more and see if it quits down.

 

[greg17887]

I have the same problem. The only thing I have not replaced or done is the cutless bearing. So I will haulout the boat and replace the cutless bearing.

 

[Benny]

As long as it is not a continuous noise pointing to a bad cutlass bearing or a faulty transmission I would not worry much about it. I would keep it under observation and would try to pinpoint the source to prevent a buddying problem from developing further. Unless you have a dripless I would definitely readjust the packing gland as it would be the most probable source. I would run the engine through its paces while tied at the dock observing the motion of engine and shaft while I would try to replicate the noise. Excessive engine vibrations and worn motor mounts could induce play and take shaft out of alingment momentarily. Whinning noises that come and go are sometimes very hard to diagnose. Good luck.

 

[RichH]

Common problem if the FLAX packing in the stuffing box has totally dried out due to the boat being out of the water for a LONG time.

First, identify exactly WHERE the 'squeel' is coming from. Just put a long 'hose' to your ear and move it around near the stuffing box, back of the hull, etc. with the prop turning at the rpm that causes the 'loudest squeel' and the boat tied to the dock. Dont get your necktie, etc. wrapped around the spinning shaft when holding the hose to your ear.

If you identify the sound coming from the stuffing box and are 'mechanically inclined', just open the adjusting nuts a wee bit until you are getting a 'quick succession' of drips, turn on the engine and engage the prop to let the flowing water spread all over the packing, tighten back to 'normal' and let sit a few day. The water from the 'drips' spread over the packing surface should begin to move (by capillary action) more water into the packing, the packing will absorb more water and begin to soften and swell back to normal dimensions, etc. The sound should stop as soon as the packing fully 'wets-out'.
If this solves your problem, at next normal haulout, replace the packing with GFO braided 'teflon - PTFE' packing.

If the boat has a 'drip-less' packing system (shaft seal, etc.), further investigation is mandated .... pronto.

 

[Maine Sail]

Others have given good advice. Here's one more area to consider. Often times if a prop has worn the tips of the blades or over time they have become a sharper edge rather than a squared off edge the prop can make a whistling noise or create a harmonic vibration that sounds like a whistle or squeal at certain RPM. The fix, if nothing else pans out, is to have a prop shop balance and condition the prop and its edges.

 

[Alex Dare]

singing

Sounds like you have a singing prop. Fairly common on new props out of the box. What happens is the sharp squared off edges of the prop blade cause a resonance to develop at certain shaft speeds. The fix is to take a file and very slightly blunt off that sharp edge. Or you can just ignore it

 

[Warren Milberg]

As indicated by the above posters, you probably have a packing gland packing issue that may be resolved by either adjusting the compression nut or replacing the packing material. Having recently replaced my packing gland material with braided teflon PTFE, it did whine for a few hours and required a number of compression nut adjustments during the break-in period.

Also alluded to by Stu, make sure your transmission is full of the right fluid. I think a lot of sailors tend to ignore checking the transmission fluid on a regular basis.

 

[truckman]

Can I file my prop myself

I think my new prop on my 2005 Catalina has been singing to me all along. At 2100 to 2900 rpm's. It only does it in forward or if you put it in nuetral while sailing. It does not make the shrill whine while tied to the dock in forward at 2100-2900. My question is can I just file the edges down a bit. My prop shop said they will do it for free. I was just trying to save myself the trouble of pulling and reinstalling in the water. Anyone done this one? Also my prop shaft only has room for a castle nut and no room for the addtional lock nut. What was Catalina thinking?

Truckman

 

[Maine Sail]

Also my prop shaft only has room for a castle nut and no room for the addtional lock nut. What was Catalina thinking?

Truckman

Catalina machines their shafts to ABYC standards and as such it should have more than enough room to fit the thin nut and the thick nut. If you can't fit both I would guess your prop may be installed incorrectly with a key binding or a prop that was not properly fitted to the shaft...

This is what the nuts should look like:

 

[truckman]

Main, This is what came with the boat when I purchased her. Do you think that the prop hub is too thick. As it sits I only have room for the castle nut. The prop is seated properly on the shaft. Also I was wondering if the whine I here could be from the Shaft sinks?

Thanks,
Dave

Catalina machines their shafts to ABYC standards and as such it should have more than enough room to fit the thin nut and the thick nut. If you can't fit both I would guess your prop may be installed incorrectly with a key binding or a prop that was not properly fitted to the shaft...

This is what the nuts should look like:

 

[JoeD]

Just had this happen to me

The very same thing happened to me last week. The end result was motor mounts sag and put pressure on the shaft causing the shaft to contact the shaft log. Found two broken mounts. When I disconnedted the shaft from the Hurth V-Drive the back of the engine when down almost an inch.

First thought it was stuffing box but the noise traveled thru the shaft. This is the first time have seen this happen in all my years of boating. So I now need new Motor Mounts and a cutlass bearing. Was real lucky that found it when I did or would need a new shaft log also.

Joe