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Propeller repair

CaptAWOL
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CaptAWOL Engager

CaptAWOL

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Yesterday approaching the narrows to Llangollen, I had a thud in which the engine slowed and the whole boat shook, from then I had a constant rattle/ vibration on the tiller. Today I reluctantly ventured into the weed hatch to find damage to one of the prop blades.

Before I go through the process of googling, I thought I'd ask For suggestions as to repair

Tomorrow I will advise CRT of this, boat draught is 28 inches

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MoominPapa Veteran II

MoominPapa

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Tomorrow I will advise CRT of this, boat draught is 28 inches

According to my Nicholson's the maximum draught for the Llangollen is 27" to Trevor, and 24" for the remainder. I wonder if that will affect CRTs reply.

 

MP, who's at Grindley Brook, heading in the same direction in a 34" deep boat.

 

I'm interested in the replies to the original query as I had a similar experience when (I think) the prop was entirely stopped by a jammed log at I was turning under the junction bridge at Great Haywood. There was a thump, and a loud whirring sound. I instinctively went for reverse, and said log shot out the back. No apparent damage, but I can feel a few nicks in the leading edge of the prop that should probably be dressed next time it's out of the water. Do Blackstone boxes whir when slipping with a jammed output?

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MtB Veteran II

MtBDonate to Canal World

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Today I reluctantly ventured into the weed hatch to find damage to one of the prop blades.

 

 

 

What damage, exactly?

 

Had to imagine minor damage causing the effect you describe. That would take half a blade missing or something really major as the propshaft just doesn't rotate all that fast.

 

What engine, box and reduction do you have? Is that a JP2 in your avatar?

Edited by Mike the Boilerman
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Slim Influencer

Slim

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Can't help with suggestions as to removal but Crowthers in Oldham are the people for repairs. Really helpful. Recently had them clean up, re pitch and balance my 17 x 12 prop. Took about 4 hours to do and a fair amount of that time was for it tocooldown. Cost about £150

 

Don't have contact details but google Crothers Propellers and it will come up

 

Frank

Edited by Slim
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MtB Veteran II

MtBDonate to Canal World

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Hmmmm good photo, but I'd class that as so trivial as to be ignorable.

 

I think the vibration you describe is caused by some other damage.

 

(Subject to you telling us what engine and reduction you have.)

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dor Veteran II

dor

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In my experience that is a little more than trivial. I've known less damage than that to set up quite a vibration, particularly at certain revs.

There is a good chance that the prop can be taken off in the water - a good boatyard should manage it. If not, marinas with slipways often offer a slip out on their trailer, stand for an hour or so and back in for a modest sum. Cost me about £80 I think for a few hours on the slipway at Swanley Bridge.

 

If it was a big bang, it could have taken out a previuosly weakened engine mount, or damaged one that had been previously good. Also could have caused some damage to the couplings depending on how it is set up.

 

Looks fairly typical of a prop picking up a large log and jamming it between the blade and the skeg.

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MtB Veteran II

MtBDonate to Canal World

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In my experience that is a little more than trivial. I've known less damage than that to set up quite a vibration, particularly at certain revs.

 

 

Yes but you have a modern fast revving engine. The OP appears to have a JP2.

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Tony Dunkley Influencer

Tony Dunkley

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That tailshaft looks a bit small on diameter in the photo, and there's too much of it unsupported between the outer bush and the propeller boss.

The kink at the tip of one blade isn't very serious and will be a relatively easy fix, but the tailshaft may well be bent, and certainly should be checked.

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CaptAWOL Engager

CaptAWOL

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Most likely a flat battery

Fully charged battery, getting a resistance turning flywheel seems to be on the injection of 1 cylinder inlet & exhaust valves operating as they should, checked inside and nothing obvious

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MtB Veteran II

MtBDonate to Canal World

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Fully charged battery, getting a resistance turning flywheel seems to be on the injection of 1 cylinder inlet & exhaust valves operating as they should, checked inside and nothing obvious

 

 

That is to be expected, the compression stroke provides substantial resistance!

 

Are you saying the resistance is missing on cylinder 2?

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Claude Collaborator

Claude

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I don't think the dent in that prop blade is trivial at all. It could be ignored if you wish, but will certainly make a difference in terms of vibration and long term wear of stem gland etc.

 

I had a similar dent repaired at Noris in Isleworth and it made a big difference.

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CaptAWOL Engager

CaptAWOL

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That is to be expected, the compression stroke provides substantial resistance!

 

Are you saying the resistance is missing on cylinder 2?

Numpty moment must of occurred, couldn't of had one decompression valve in properly when testing rotation of engine. Solved starting problem, clutches gone in starter motor and replaced today
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MtB Veteran II

MtBDonate to Canal World

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Numpty moment must of occurred, couldn't of had one decompression valve in properly when testing rotation of engine. Solved starting problem, clutches gone in starter motor and replaced today

 

 

What excellent news. A numpty moment if INFINITELY preferable to a broken crankshaft moment, which is what I was wondering!

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