Guido999
New member
Hi All,
Apologies - long post coming….
I have a dilemma and a slight mystery I’d like any advice on how to solve. I have had my Storebro 410 Commander for about five years now and have done a couple of hundred hours of very happy cruising around the Irish Sea….I’ve tended to service her myself and this year, after her service I also had her lifted and anti fouled etc. As the starbord shaft seal was beginning to show a little too much weeping and the jubilee clips were going rusty I decided to have new PSS seals put on both props. I didn’t do this myself as it would have been too much for me but had an excellent boat engineer that did it for me when she was out of the water.
When the job was done, on relaunch it became immediately apparent that the starbord prop had a really bad vibration above 2400rpm that gets worse and worse at higher revs (so definitely not a ‘harmonic’ issue). There’s a video of this here:
There was no noticeable vibration before we lifted her and the only work done on the running gear was changing the prop seals. This involved uncoupling and sliding back the shafts. Having looked through the forums and discussed extensively with the engineer, the new vibration comes down to the following possible causes, that we are working slowly through:
1. Propeller issue - there is indeed a very large ding in starbord prop - but it has been there for at least four years, but the vibration only started after the shaft seals were changed;
2. Shaft issue - we have taken the shaft off and rolled it on a machine shop floor and it seems to roll completely straight (albeit we don't have the facilities to properly test prop balance or whether the shaft is running true);
3. Couplings - both engines are fitted with R&D flexible couplings. Visually the starbord coupling looks to be in the same condition as the port coupling (which has no vibration issues).
4. Cutlass bearing - The starbord cutlass bearing was indeed absolutely knackered and after lifting the boar for the second time we have now replaced this, but the vibration has continued unabated when we put her back in again.
5. Engine mounts - they don't look obviously knackered, although it is hard to tell....but if engine mounts are the problem it doesn't explain why we went from no vibration to immediate bad vibration when just changing the prop seals.
6. An alignment issue between engine and shaft - we have to lift the Boat out again to test this one.
7. The PSS seals themselves have done something: I haven’t read anything anywhere to suggest that PSS seals could cause such bad whipping, so although this is the only thing that was changed, this seems unlikely?
So the bottom line is that something changed when we changed the shaft seals. It doesn't seem like it is the props or the shaft being bent or dinged, because the vibration wasn't there before lifting her to change the seals. We had high hopes that it was the cutlass bearing as it was so obviously knackered - so we changed this, put her back in again, but the vibration was still horribly evident. The only possible thing we can think is this:
The boat was built in 2008 and, to my knowledge, the shafts have never been removed before. When the starbord shaft was removed to change the seal, the R&D coupling was taken off - when we put it back on again we didn't necessarily put it back on again in exactly the same position (it is circular with six bolts so there are six possible positions it could be put back together in).
If there had been a slight distortion in the coupling (it is flexible) because over the last fifteen years the engine has moved slightly / the mounts have settled or softened - the R&D coupling might have hidden a change in alignment by shaping itself accordingly - hence no vibration before changing the seals. If we didn't then locate the coupling it in exactly the same orientation, then could this cause enough of a new misalignment to create the whipping shaft? Does that sound feasible? Has anyone had this experience before?
So my dilemma is this: Our next step is to lift her for the third time (argh!!), install a new R&D coupling and this time check and adjust the engine alignment. Although it doesn’t seem like it would be a shaft or prop issue, there is a large ding in the starbord prop (which has always been there). See below for a pic of it from a couple of years ago.
So I am debating whether to have the troublesome shaft removed and send it and the prop to a specialist to test / balance and clean etc…The trade-off is this - if I do send it off, it is going to take a good few weeks of the summer season to get them back and installed (I’ve already lost six weeks so far); if I don’t send them off and just get a new coupling fitted and the engine aligned, then if this still doesn’t fix the vibration I am going to kill myself for not sending them off and it will cost me another few hundred on a lift!!!
At the moment I am leaning toward sending them to a specialist anyway, because the starbord cutlass bearing was knackered, but not the port one, because there is a starbord prop ding and because the original shaft seal was knackered on the starbord side only, it makes me think there was something going on, on the starbord shaft already - but maybe the R&D coupling simply concealed the problem until we buggered about with the coupling…so maybe better to get the prop done anyway?
So does anyone have any advice or thoughts on this for me? In particular thoughts on our diagnosis so far or if there’s anything else that we should be checking as well.
Many thanks in advance for all of your help with this!
Best wishes
Guy.
Apologies - long post coming….
I have a dilemma and a slight mystery I’d like any advice on how to solve. I have had my Storebro 410 Commander for about five years now and have done a couple of hundred hours of very happy cruising around the Irish Sea….I’ve tended to service her myself and this year, after her service I also had her lifted and anti fouled etc. As the starbord shaft seal was beginning to show a little too much weeping and the jubilee clips were going rusty I decided to have new PSS seals put on both props. I didn’t do this myself as it would have been too much for me but had an excellent boat engineer that did it for me when she was out of the water.
When the job was done, on relaunch it became immediately apparent that the starbord prop had a really bad vibration above 2400rpm that gets worse and worse at higher revs (so definitely not a ‘harmonic’ issue). There’s a video of this here:
There was no noticeable vibration before we lifted her and the only work done on the running gear was changing the prop seals. This involved uncoupling and sliding back the shafts. Having looked through the forums and discussed extensively with the engineer, the new vibration comes down to the following possible causes, that we are working slowly through:
1. Propeller issue - there is indeed a very large ding in starbord prop - but it has been there for at least four years, but the vibration only started after the shaft seals were changed;
2. Shaft issue - we have taken the shaft off and rolled it on a machine shop floor and it seems to roll completely straight (albeit we don't have the facilities to properly test prop balance or whether the shaft is running true);
3. Couplings - both engines are fitted with R&D flexible couplings. Visually the starbord coupling looks to be in the same condition as the port coupling (which has no vibration issues).
4. Cutlass bearing - The starbord cutlass bearing was indeed absolutely knackered and after lifting the boar for the second time we have now replaced this, but the vibration has continued unabated when we put her back in again.
5. Engine mounts - they don't look obviously knackered, although it is hard to tell....but if engine mounts are the problem it doesn't explain why we went from no vibration to immediate bad vibration when just changing the prop seals.
6. An alignment issue between engine and shaft - we have to lift the Boat out again to test this one.
7. The PSS seals themselves have done something: I haven’t read anything anywhere to suggest that PSS seals could cause such bad whipping, so although this is the only thing that was changed, this seems unlikely?
So the bottom line is that something changed when we changed the shaft seals. It doesn't seem like it is the props or the shaft being bent or dinged, because the vibration wasn't there before lifting her to change the seals. We had high hopes that it was the cutlass bearing as it was so obviously knackered - so we changed this, put her back in again, but the vibration was still horribly evident. The only possible thing we can think is this:
The boat was built in 2008 and, to my knowledge, the shafts have never been removed before. When the starbord shaft was removed to change the seal, the R&D coupling was taken off - when we put it back on again we didn't necessarily put it back on again in exactly the same position (it is circular with six bolts so there are six possible positions it could be put back together in).
If there had been a slight distortion in the coupling (it is flexible) because over the last fifteen years the engine has moved slightly / the mounts have settled or softened - the R&D coupling might have hidden a change in alignment by shaping itself accordingly - hence no vibration before changing the seals. If we didn't then locate the coupling it in exactly the same orientation, then could this cause enough of a new misalignment to create the whipping shaft? Does that sound feasible? Has anyone had this experience before?
So my dilemma is this: Our next step is to lift her for the third time (argh!!), install a new R&D coupling and this time check and adjust the engine alignment. Although it doesn’t seem like it would be a shaft or prop issue, there is a large ding in the starbord prop (which has always been there). See below for a pic of it from a couple of years ago.
So I am debating whether to have the troublesome shaft removed and send it and the prop to a specialist to test / balance and clean etc…The trade-off is this - if I do send it off, it is going to take a good few weeks of the summer season to get them back and installed (I’ve already lost six weeks so far); if I don’t send them off and just get a new coupling fitted and the engine aligned, then if this still doesn’t fix the vibration I am going to kill myself for not sending them off and it will cost me another few hundred on a lift!!!
At the moment I am leaning toward sending them to a specialist anyway, because the starbord cutlass bearing was knackered, but not the port one, because there is a starbord prop ding and because the original shaft seal was knackered on the starbord side only, it makes me think there was something going on, on the starbord shaft already - but maybe the R&D coupling simply concealed the problem until we buggered about with the coupling…so maybe better to get the prop done anyway?
So does anyone have any advice or thoughts on this for me? In particular thoughts on our diagnosis so far or if there’s anything else that we should be checking as well.
Many thanks in advance for all of your help with this!
Best wishes
Guy.
