Damage resulting from fouled propeller

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12 Year Plan B-)

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Yesterday my prop got fouled with a length of anchor warp. The whole boat was shaking and there was an awful grinding sound. It sounded and felt like I had gone aground on a sand/mud/gravel bottom. I lost any meaningful propulsion but the engine didn't stall.

My question is, what was the grinding sound? I initially thought that the shaft coupling bolts must have sheared but it all looks ok. Nothing has sheared on the propeller end either: it still engages positively when the engine is in gear and rotates smoothly, which suggests the gear box is not trashed. The engine is a Yanmar YSB8. Does anybody know if my setup features any kind of clutch? Could I have trashed that?

Thanks in advance
 
There is a plate clutch in the YS transmission. Its purpose is to shift between forward and astern gears. Can't really say if your grinding noise was it slipping, but I'd think that the engine would stall before that happened if the clutch was in good condition in the first place.
Propellors with debris wrapped around them can cause nasty sounds and vibrations.
If things seem OK now, I'd just be thankful and carry on.
Maybe you should check for a slightly bent shaft.
 
I would inform my insurance and ask for their guidance as to what I should do next.
A friend of mine had a rope wrap itself round his prop and didn't give it another thought. After speaking with the insurance company about the incident they had the boat hauled out onto the hard for inspection. The result was that the P-bracket had been slightly bent necessitating its removal and re-attachment, internal reinforcement for the bracket, re-alignment of the engine, etc. The bill from the yard was substantial but the insurers picked up the tab.
 
Consider fitting a prop cutter after the problem is sorted. My 'Stripper' cut through 1inch manilla holding a crab pot off Felixstowe, and has done good work on other occasions.
 
yerffoeg said:
Consider fitting a prop cutter after the problem is sorted. My 'Stripper' cut through 1inch manilla holding a crab pot off Felixstowe, and has done good work on other occasions.
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I had a rope cutter on my shaft when I fouled a pot marker, 5 metres off the SHM going into Ayr, but I still fractured my P bracket and bent the shaft. Not overly convinced by their efficacy.
 
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Quiddle said:
I had a rope cutter on my shaft when I fouled a pot marker, 5 metres off the SHM going into Ayr, but I still fractured my P bracket and bent the shaft. Not overly convinced by their efficacy.
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There lot of rope utter on the market , which one I you have ? Although I don't have one on this boat , we had stripper on two other boats and they have came in handy many a times , they do work I give them that . If I had to fit a rope cutter it be a stripper .
 
A few weeks ago we had a prop fouling incident whilst motoring back from the Scillies with no wind. Just off Lizard point pushing against 1.5 knots of tide, we crossed a very large and thick area of kelp. We definitely heard a distinct change in engine note so the prop had obviously struggled somewhere along the lines. We still had full propulsion and forward and reverse gears, but boat speed was adversely affected.

We could also hear a knocking sound, which was concerning, particularly after maintaining 8 hours of consistent engine hum. We stopped the boat and engaged forward and reverse in an attempt to clear the problem. The knocking sound improved but didn't go away.

I later spoke to an engineer about the problem as I was concerned about a bent shaft (or other damage), and he advised that any fouling would likely present itself with unusual noises, whether rope or kelp. Used the boat a couple of weeks later and all was fine.
 
alexincornwall said:
A few weeks ago we had a prop fouling incident whilst motoring back from the Scillies with no wind. Just off Lizard point pushing against 1.5 knots of tide, we crossed a very large and thick area of kelp.
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....ermm, where exactly were you? If it was genuinely kelp sounds like you were nearly aground. What time and day was it, how far off the light? I think you may mean a large patch of floating weed, kelp doesn't float.
 
fisherman said:
....ermm, where exactly were you? If it was genuinely kelp sounds like you were nearly aground. What time and day was it, how far off the light? I think you may mean a large patch of floating weed, kelp doesn't float.
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Ok fair, but slightly pedantic point. I'll correct with floating weed then. Approx. 1.5nm 24m of water, 1300. Whatever it was, it was thick.
 
Had me worried for a moment! The weed gathers where two tides cross, as the last of the SW bound ebb and first of SE bound flood off the point, along with any other floating debris, plastic, discarded rope, netting, etc, (and fish). I always try to avoid if seen in time, if only for the sake of the water intakes.
 
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