annageek
Member
We were heading into Newton Creek a couple of weekends ago. With full revs near the entrance (it was a spring tide and we were heading in on the ebb) I noticed the engine tone drop barely perceptably and a short while after a horrible noise. It was a sort of periodic squealing / screaching noise that corresponded with the engine revs. I have no idea what it was but you could feel it through your feet. However, I dropped the revs to the minimum to just make progress against the flow and managed to get moored. My partner dove on the prop and she found a ton of weed mangled around it - the sort of light green, wet-cotton-wool type stuff.
Anyway, since then, there's been a slight, but very noticable 'wobble' in the prop shaft where it enters through the stern gland. Video with slo-mo here:
. The gland is a touch more drippy than it was before, thought no deluges yet. Before all of this, I'm pretty sure it was running almost perfectly true with no discenrnable wobble. Weirdly, at full revs, the wobble all but disappears, but it's definitely there at everything from tickover to 95%.
Hand rotating the shaft shows the run out is between about 1mm and 2mm (measured by looking at the shadow of a torch on a ruler - not a DTI!). Not a huge amount, but despite the flexible shaft coupler, this vibration looks to be coupled into the engine and the whole thing's moving a bit more on the engine mounts.
Questions are:
1. Any idea what could have happened?
2. Is 1-2mm runout too much / potentially damaging for the gearbox / stern gland etc.
The boat seems to run OK. I can't repeat the problem with the screaching noise, even after running at full revs for several minutes to test. My preference is to see out the rest of the season and take a closer look when she's out of the water over winter.
Just for context, it's a 26' Westerly Griffon with a Volvo Penta MD7A 13hp engine.
Anyway, since then, there's been a slight, but very noticable 'wobble' in the prop shaft where it enters through the stern gland. Video with slo-mo here:
Hand rotating the shaft shows the run out is between about 1mm and 2mm (measured by looking at the shadow of a torch on a ruler - not a DTI!). Not a huge amount, but despite the flexible shaft coupler, this vibration looks to be coupled into the engine and the whole thing's moving a bit more on the engine mounts.
Questions are:
1. Any idea what could have happened?
2. Is 1-2mm runout too much / potentially damaging for the gearbox / stern gland etc.
The boat seems to run OK. I can't repeat the problem with the screaching noise, even after running at full revs for several minutes to test. My preference is to see out the rest of the season and take a closer look when she's out of the water over winter.
Just for context, it's a 26' Westerly Griffon with a Volvo Penta MD7A 13hp engine.
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