pearley Posted June 14, 2018 Report Share Posted June 14, 2018 (edited) We have just had our stern gear replaced, the prop because I'd taken a chunk out of it due to hitting something solid and the shaft, cutlass bearing and dripless stern gland (Volvo stuffing box) due to wear. On leaving the dock and heading up the canal we now have a whine in forward gear only from tickover to just over 1000 rpm. With the previous propellor there was about one finger of shaft exposed between the prop and hull. I can now get two fingers in easily. This gives less than an inch clearance between the end of the shaft and the leading edge of the rudder blade. Could this be the cause? It's a Vetus prop, shaft and bearing with a Vetus badged Centaflex coupling. Just the gland seal is Volvo Penta. Edited June 14, 2018 by pearley Link to comment Share on other sites More sharing options...
Hudds Lad Posted June 14, 2018 Report Share Posted June 14, 2018 sounds like you've got a Millennial round your prop 1 1 Link to comment Share on other sites More sharing options...
nicknorman Posted June 14, 2018 Report Share Posted June 14, 2018 Could be prop singing. Usually more of a screech than a whine and over quite a narrow rev range. Link to comment Share on other sites More sharing options...
Boater Sam Posted June 14, 2018 Report Share Posted June 14, 2018 (edited) At certain blade speeds you can get a "chirp" which is more of an off board noise, easier to hear from outside or in a nearby boat. This is dependant on the blade shape and edges and the position relevant to the rudder and hull. A "whine" after repair because of a damage event would suggest gearbox or stern gland to me. Particularly if noticeable on board. Did they hammer the blade off the shaft? So what precisely is the noise like? Edited June 14, 2018 by Boater Sam smellings Link to comment Share on other sites More sharing options...
Cheshire cat Posted June 14, 2018 Report Share Posted June 14, 2018 I think the words "with the previous propeller" are significant. I bet the previous one was more substantial than the replacement. I and others have complained about whining propellers. It is annoying if you suffer from it. In our case it was impossible to ignore. Sometimes filing the edges does the trick How far the shaft extends beyond the stern gland seems to affect things too. Our noise didn't go away until we replaced the propeller. Link to comment Share on other sites More sharing options...
Boater Sam Posted June 14, 2018 Report Share Posted June 14, 2018 Cheap prop used? Happens a lot. Go see Crowthers for a proper one. Link to comment Share on other sites More sharing options...
pearley Posted June 14, 2018 Author Report Share Posted June 14, 2018 2 hours ago, Boater Sam said: At certain blade speeds you can get a "chirp" which is more of an off board noise, easier to hear from outside or in a nearby boat. This is dependant on the blade shape and edges and the position relevant to the rudder and hull. A "whine" after repair because of a damage event would suggest gearbox or stern gland to me. Particularly if noticeable on board. Did they hammer the blade off the shaft? So what precisely is the noise like? It's a whine increasing in intensity until just over 1000 revs when it disappears. Stern gland is a dripless Volvo one and was replaced. Bearing was replaced. 2 hours ago, Cheshire cat said: I think the words "with the previous propeller" are significant. I bet the previous one was more substantial than the replacement. I and others have complained about whining propellers. It is annoying if you suffer from it. In our case it was impossible to ignore. Sometimes filing the edges does the trick How far the shaft extends beyond the stern gland seems to affect things too. Our noise didn't go away until we replaced the propeller. Engineer has been back and tapped shaft further into the coupling. Whine when in gear whilst still tied up seems to have gone now. We'll see/hear properly when we move tomorrow. 2 hours ago, Boater Sam said: Cheap prop used? Happens a lot. Go see Crowthers for a proper one. Old and new props are both Vetus Link to comment Share on other sites More sharing options...
Bee Posted June 15, 2018 Report Share Posted June 15, 2018 I would guess that this is prop singing, usual cure is apparently filing the edges to sharpen them but when I had a singing prop it just went away eventually, I think that when the prop grew a coating of what is probably metal deposits from the anodes and hull it changed it just that little bit. I try not to think about that too much. Link to comment Share on other sites More sharing options...
Tony Brooks Posted June 15, 2018 Report Share Posted June 15, 2018 8 hours ago, Bee said: I would guess that this is prop singing, usual cure is apparently filing the edges to sharpen them but when I had a singing prop it just went away eventually, I think that when the prop grew a coating of what is probably metal deposits from the anodes and hull it changed it just that little bit. I try not to think about that too much. I suspect a few nicks from stones altered the vibration frequency of one or two blades a little. Link to comment Share on other sites More sharing options...
Scholar Gypsy Posted June 19, 2018 Report Share Posted June 19, 2018 This is what I did - involving some filing, as described on an earlier post here (link is in the blog). Worked a treat.https://nbsg.wordpress.com/2016/11/05/blacking-and-no-more-singing/ Link to comment Share on other sites More sharing options...
pearley Posted June 19, 2018 Author Report Share Posted June 19, 2018 (edited) I have been sent a pdf from Vetus showing what to do. Very much the same as you. We'll have to live with it until our next dry docking by which time it might well have gone or changed. Edited June 19, 2018 by pearley Link to comment Share on other sites More sharing options...
Señor Chris Posted June 19, 2018 Report Share Posted June 19, 2018 (edited) 2 hours ago, Scholar Gypsy said: This is what I did - involving some filing, as described on an earlier post here (link is in the blog). Worked a treat.https://nbsg.wordpress.com/2016/11/05/blacking-and-no-more-singing/ When you say "an angle of 30 degrees", does that mean 30 deg to the edge of the blade and 60 deg to the face? Edited June 19, 2018 by Señor Chris Link to comment Share on other sites More sharing options...
Scholar Gypsy Posted June 19, 2018 Report Share Posted June 19, 2018 17 minutes ago, Señor Chris said: When you say "an angle of 30 degrees", does that mean 30 deg to the edge of the blade and 60 deg to the face? No, a 30 degree angle between the file and the face of the blade. I kept going until the tip had reduced in thickness by about 50%. if you enlarge the photo in my blog you can see the size of the filed area - the shiny bit, about 2mm. I reckon I halved the thickness of the tip from 2mm to 1mm (sin (30deg) = 0.5). Link to comment Share on other sites More sharing options...
Señor Chris Posted June 19, 2018 Report Share Posted June 19, 2018 12 minutes ago, Scholar Gypsy said: No, a 30 degree angle between the file and the face of the blade. I kept going until the tip had reduced in thickness by about 50%. if you enlarge the photo in my blog you can see the size of the filed area - the shiny bit, about 2mm. I reckon I halved the thickness of the tip from 2mm to 1mm (sin (30deg) = 0.5). OK, thanks - I'm out of the water at the moment so I'll give it a go. Link to comment Share on other sites More sharing options...
BruceinSanity Posted June 19, 2018 Report Share Posted June 19, 2018 2 hours ago, pearley said: I have been sent a pdf from Vetus showing what to do. Very much the same as you. We'll have to live with it until our next dry docking by which time it might well have gone or changed. People have been known to do it underwater. Filing the prop, that is. Link to comment Share on other sites More sharing options...
Boater Sam Posted June 19, 2018 Report Share Posted June 19, 2018 As well. Link to comment Share on other sites More sharing options...
pearley Posted June 20, 2018 Author Report Share Posted June 20, 2018 21 hours ago, BruceinSanity said: People have been known to do it underwater. Filing the prop, that is. I know and I've filed dings myself but the amount Vetus and Simon talk about is quite considerable and fairly specific. To do it properly would need fairly clear water, at least enough to see one blade at a time, not something easily found around Birmingham. I'll see how it is after a stones, etc have been kicked up and taken their toll on the prop. singing prop info.pdf Link to comment Share on other sites More sharing options...
WotEver Posted June 20, 2018 Report Share Posted June 20, 2018 1 hour ago, pearley said: singing prop info.pdf Interesting info, thanks Link to comment Share on other sites More sharing options...
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