Fouled prop - next steps?

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Balbas

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I was arriving at a marina last night and the engine suddenly stopped. Wouldn't re-start unless out of gear, and when going into gear it immediately stopped again.

With the pressing need to avoid crashing into expensive yachts I abandoned the engine and we made it into a berth without playing expensive skittles.

Once safely tied up we spotted some thin dark line trailing from the boat, so reeled it in -there must have been 30m of it. Unable to pull it loose of the prop, and feeling unwilling to get in the water in a marina and with the approaching gloom I restarted the engine and crashed it into gear giving it loads of revs - knowing that I have a rope cutter on the prop shaft - and it now seems to go in and out of gear at idle again without problem. But... The tail of the line that I cut off is still attached. Obviously it's still bound up around the shaft, although no longer preventing rotation.

Question - can I safely leave it for now (we're on a family long weekend) and get it sorted when I can get to the drying grid. Or do I need to get it looked at immediately - I don't have a mask or wetsuit with me and I don't think the marina would be happy with me popping over the side...
 
Perhaps if you get the tail round a winch it will now free off. Running the engine in reverse keeping all fingers clear, may help.
 
Did you check that the shaft was turning again after putting it into gear and giving a lot of throttle. At least you would know nothing sheared in gearbox. Or check that you are getting thrust against mooring lines. I wouldn't worry too much if the boat is secure with no leaks and you can crawl to a nearby drying grid later.

I had a huge sheet of plastic melted to my prop. many years ago. The engine did run in gear but sounded like a can full of ball bearings being thrown around. Luckily the BUKH DV20 has a spring loaded gear which disengages if prop. locks up. It makes a racket until the engine is turned off but just re-engages without a problem. I expect that something would shear in other setups.
 
Invite some people over for coffee and biscuits or an early beer. On your foredeck. About fifteen lifted the stern of a First 35 enough for me to be able to get to its prop in a dinghy and cut a ball of net off.
 
Cardinal said:
Perhaps if you get the tail round a winch it will now free off. Running the engine in reverse keeping all fingers clear, may help.
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Unfortunately the remaining tail is just long enough to reach the stern. Definitely won't get it to a winch.
Mistroma said:
Did you check that the shaft was turning again after putting it into gear and giving a lot of throttle. At least you would know nothing sheared in gearbox. Or check that you are getting thrust against mooring lines. I wouldn't worry too much if the boat is secure with no leaks and you can crawl to a nearby drying grid later.

I had a huge sheet of plastic melted to my prop. many years ago. The engine did run in gear but sounded like a can full of ball bearings being thrown around. Luckily the BUKH DV20 has a spring loaded gear which disengages if prop. locks up. It makes a racket until the engine is turned off but just re-engages without a problem. I expect that something would shear in other setups.
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We've got good forward and reverse thrust against the mooring Iines, as much as normal I'd say.
anoccasionalyachtsman said:
Invite some people over for coffee and biscuits or an early beer. On your foredeck. About fifteen lifted the stern of a First 35 enough for me to be able to get to its prop in a dinghy and cut a ball of net off.
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Unfortunately we're away from home, so I don't see that bring likely at the moment.

So my concerns are - will it bind up again, and if I leave it for a bit will it damage anything (cutless bearing)?
 
Cardinal said:
Can you not tie an extension piece to the tail and so reach a winch?
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No, I don't think I can. Anyway it's a couple of mill at most - it's not mono filament and not whipping twine - seems to be some kind of stranded nylon - so I don't think I'd get purchase on a winch.
 
I would tie a knife to the end of the boat-hook and try to shorten the tail as much as possible, check carefully the stern gland or equivalent and hope for the best.
 
I popped up to the marina office this morning. Their scissors wouldn't cut it, so I looked really closely - appears to be Kevlar twine.
 
Balbas said:
Unable to pull it loose of the prop, and feeling unwilling to get in the water in a marina and with the approaching gloom I restarted the engine and crashed it into gear giving it loads of revs - knowing that I have a rope cutter on the prop shaft - and it now seems to go in and out of gear at idle again without problem.
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I'm delighted that your cutter has done its job ... but I'd be very worried about crashing an engine into gear at high revs, rope cutter or not. Personally I would try gentle revs for a few seconds in the opposite direction to which the engine was running when it jammed and then try pulling it out. However, my props are near the surface on narrow sterns so ducking under to free them is not difficult. :)

Richard
 
Balbas said:
So my concerns are - will it bind up again, and if I leave it for a bit will it damage anything (cutless bearing)?
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There’s only one answer to this question and that’s to go over the side and have a look. I suspect that nothing else will give peace of mind.

I dived on a friends boat on Friday to clear a pick-up buoy line and look over the prop and shaft. A 5 minute job but very reassuring for the owner.
 
You just might be very unlucky and have the remainder melt into a hard plastic ring on the shaft, this could then get into the nitrile of the cutless and start mangling it. Seen it once, the whole 'rubber' disappeared. It's a peace of mind thing, you won't want it to pop into your head when you are in less than perfect circumstances sometime in the future.
 
You need to visually inspect it. Get into the water or find a diver to do it.

Why risk causing serious damage to the prop, shaft, engine or any mountings?
 
Sandy said:
You need to visually inspect it. Get into the water or find a diver to do it.

Why risk causing serious damage to the prop, shaft, engine or any mountings?
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An engine-stall propwrap can easily bend a propshaft, damage coupling and even break rubber engine mounts. Also as others have said can damage cutless bearing if bits of wrap left behind. Look internally as well as at the prop/cutless/P-bracket itself.
 
I'd want someone to look at it but they need to be very wary of the rope cutter. I carry a mask for our own purposes. Don't really need a snorkel or wetsuit. If you can't buy one I'd ask a likely person on a neighbouring boat if you can borrow one, you might find a volunteer to get wet for you that way.

Once we picked up something on our prop that stalled the engine, and found later that the gearbox output shaft seal had got displaced by the shock, revealed by the gearbox oil emptied into the bilge...
 
I like the idea of a foredeck party. We have done this on a small boat and a Sadler 32 effectively. Depending on conditions, an underwater camera or inspection device might also work.
 
jwilson said:
An engine-stall propwrap can easily bend a propshaft, damage coupling and even break rubber engine mounts. Also as others have said can damage cutless bearing if bits of wrap left behind. Look internally as well as at the prop/cutless/P-bracket itself.
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Got a heavy line around ours while 'helping' a lifeboat. Forced it into gear ( as we were ourselves getting into danger) Bent shaft and damaged stern gear...lots of dosh!!
 
Norman_E said:
If you are in a marina, just ask the office if they have a diver on the staff.
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Health and safety can make this expensive. A friend lost something in Brighton some years ago but a diver would have involved a minimum of three, two in the water and one standing by. His son, a qualified diver, snorkelled it when nobody was looking.
 
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