Singing propeller - help!

[max]

I have just been told that the annoying whining noise that now develops between 1700 and 2200 rpm is caused by a 'singing propeller'. This follows the fitting of a new prop and stern seal to the Volvo 2030 which is fitted in my Westerly Pentland.

It has been suggested that if I lightly file the leading edges of the prop next time it's hauled out this will sort it. Given that this may not be until January I am in danger of being driven completely mad by then.

Any advice about how else to sort it would be gratefully received.

(I could of course sail most of the time but some members of the family, when aboard, have yet to be reconciled to the fact that sailing vessels tip under sail!)

Thanks.

 

[Twister_Ken]

Semantics

Do NOT use the word tip in earshot of family members. It is associated with unpleasant thoughts like tip-up, tip-out, rubbish-tip, tip-in, etc

Instead, pull your Breton cap down a little more firmly, take a lungful of old navy shag from your salt-stained briar and proclaim, "Ah, she's heeling nicely to a friendly sailing breeze."

 

[max]

Re: Semantics

Point taken entirely! Alternatively I could buy a cat or simply not take them with me.

 

[Chris_Stannard]

I would be careful of filing the edge of your propellor since you might unbalance it and it would then viabrate, which could be worse. Howeve the noise might be caused by a nick in the leading edge of one of the blades, in which case removing any rough edges might help.

Who told you the noise was caused by the propellor and have your checked with the manufacturer/people who sold it to you?

Only other practical suggestion is not to motor between 1700 and 2200 rpm.

Chris Stannard

 

[max]

I was told that it was 'singing' by the engineers who fitted it.

And unfortunately 1700 to 2200 is absolutely the ideal cruising rev range for 5 - 6 knots. Sods law!

 

[jleaworthy]

When I had this problem with a new propeller I was told by Mike French of Brightlingsea, the supplier, that the unpleasant noise was caused by votices being shed from the blunt TRAILING edges of the propeller blades. The only solution was to haul out and to carefully file those edges and then to try again. Eventually it worked!!

 

[philip_stevens]

I fully concur with your post.

I sailed on a container-ship with a singing prop that was almost unbearable (at certain revs at certain cargo weight), and this was caused by the trailing edge. The prop company, Stone-Manganese, had the ship ballasted as far down by the head as possible, constructed a tent over the prop - still under water - filled the tent with air, so that the divers were able to work in the dry, and then ground the trailing edge of the five blades of the prop. Result - silence.

regards,
Philip

 

[johnt]

Re: Semantics

or you could stop trying to carry full sail in a force 5!........reduce sail and sail upright I say ......you go just as fast !

 

[Guest]

As one of the developers of the U.N. "Silent Prop for subs". Fix the trailing edge of your prop the cavitation is what is causing the singing!
Good Luck
Gene

Keep on Learning!!

 

[zephyrsailor]

max i know someone who would be easily bribed into diving on ur boat to file ur prop!

 

[airbubble]

Re: a tip does wonders with

fuel barge staff, waitors or waitresses and the like !
just be carefull not to tip-over.

you could tip your family overboard.......

 

[airbubble]

from your description; indeed the prop.
Definitely the TRAILING edge though. Prop manufacturers can and should supply you with a prop that already has an anti-singing edge. You should easily see it on the rudder side. If this is not enough (as it has not been with VETUS and Radice props for some time now) you can indeed easily file a flatter slope on the trailing edge. We preferred to actually do this both sides of the trailing edge and sort of round-off the possibly (too)sharp edge you created. It is often so that the standard trailing edge does not have its anti-singing edge far enough towards (over) the blade tip.

Other solutions:
change the shape of the hull to alter the water flow towards the prop.
always sail in circles whilst using these revs. The changed waterflow around the rudder will stop the singing.
Throw a big log in front of your boat and try to catch it in your prop. It might take a few runs, as this only happens when you DONT want it. The damage to the prop will stop the singing.
Don't be afraid of causing unbalance. You'd have to file away abit before that happens and furthermore, a singing prop is 110 % well balanced. Because it is so well balanced, it sings. If one of the blades is slightly out of tune, again the singing is gone. So hit one blade with a hammer might solve this.

Look at it the other way; they have actually sold you a perfect prop and it is singing a way happy and nicely with your boat at a happy speed !

 

[ponapay]

The same has happened to me and I have found the cure through trial and error.

I have found that when the shaft is stopped in one particular position the singing stops and peace reigns. The shaft is now marked and stopped in the same position every time when sailing.

On lift out I found that there was one blade which ended up just clear of the hull shading and, presumably, out of the waterflow.

 

[hans]

I see you have gotten some good advice on your singing prop already. We had the exact same problem - and at the same revs - after changing engine and prop on our 31´Monsun in Tromsø a couple of years ago. I only discovered what it was from these "reader-to-reader" pages...

We found a leaflet called "Around the engine" from Vetus at the London Boat Show, where there is a diagram showing where and how much to file off your propeller blades. However before we had the boat hauled the problem simply dissapeared - after approx 300 engine hours. No more singing propeller at any revs. What exactly has happened with the propeller I do not know, but I am very pleased with the result....

So maybe patience is good medicine for a season or two? Good luck!

Hans
Oslo, Norway

 

[max]

Thanks to everyone for the advice various.

Amazingly, and thankfully, the problem seems to have stopped of its own accord after about 15 hours of running. I can only assume that the this is something to do with acquiring a bit of dirt and verdigris (?) which has taken the shine and therefore the perfect flow off the prop surface.