fouled prop, cleared, now prop shaft won't turn freely

[skwanderer]

As I was pulling into my slip at dusk, I lost both engines one right after the other (have twin screws), e.g., the engines died as soon as I put into gear, under load. With help of searching through this forum (after I managed to get back into the slip with a lot of help), I deduced the problem was maybe something had bound around the props.

The next day I dove in and found my second spring line had fallen over the side and was bound up in the props. I cut it lose, but the line was very taught (given the line was still secured to the side up top when it became entangled).

The next day when I started to take the boat out, I heard a high pitched squealing sound like that of a loose fan belt in cold weather coming from the area around the shaft log/stuffing box. I was already untied from the dock at that point, so I just motored slowly around for a bit to see if the noise would stop. The squealing went away after a few minutes, but the prop shafts do not rotate freely at idle now. When in neutral, I should be able to manually give them a turn, rotating them at the coupler/stuffing box area, but they are very stiff and don't freely rotate at all. I did motor a few more minutes just to see if the stuffing box area got warm, and it did on the port one (not the starboard one). The port prop is the one that got tangled first and most. Also while underway I looked to see if there was any wobble in the prop shaft or anything else awry, but nothing seemed out of orbit.

All I can tell so far is that the props on both don't freely rotate at idle, nor can I even rotate them by hand. Thoughts as to why and what's going on with this new damage I've now self-inflicted?

[flyingfin]

Must have been a strong spring line! It may have got so tight it twisted the shaft and now it is binding in the cutlass. Time for a haul out

[skwanderer]

Originally Posted by flyingfin

Must have been a strong spring line! It may have got so tight it twisted the shaft and now it is binding in the cutlass. Time for a haul out

Yes, it was a very long and strong line

I was afraid that a haul out and cutlass inspection/repair/replace may be in order...

My propshaft is 1.5 inches diameter and prolly around 4-6 feet long, so I don't know how much torque it would take to bend it.

[Manateeman]

The shaft maybe fine but it is just part of a system. Engine beds? Coupling?
Strut? Lot of places to check.
M Crew

[tkeithlu]

My "most likely" bet is that the line got between the prop and the bearing, and is wrapped very tightly. If that's the case, at most you will have to remove the props and cut away the very tight rope. That's not a disaster, or involve damage to your power train.

[skwanderer]

Indeed, in the murky water (and short breath) I had to take a look, maybe there is more line still wound up down there between strut and prop.
Here's what it looks like normally: https://www.cruisersforum.com/forums...ture24482.jpeg

I've no idea how strong the struts are to take a yank sideways like the fouled line did.

[FuneSF]

I had a similar fouling on my boat. The bow line (a long one) wrapped around the prop while motoring at around 2700 rpm. There was a fair amount of damage.

The problem with our type of foulings is that the angle of taught line actually pulls the shaft and engine aft when it wraps around the shaft. You would think it would pull the shaft into the boat. But, the opposite happened. This throws everything out of alignment. It pulled my shaft aft into the rudder and put a hole in it.

I have had the boat at the yard for repairs the past two months. I needed the rudder repaired; new engine mounts; new shaft; prop rebalanced; new dripless shaft seal; new cutlass bearing and the transmission repaired. It has been a bit of an ordeal..

Good luck. You were likely running the engine at a much lower rpm. Hopefully, you will escape this fate.

[skwanderer]

Originally Posted by FuneSF

I had a similar fouling on my boat. The bow line (a long one) wrapped around the prop while motoring at around 2700 rpm. There was a fair amount of damage.

The problem with our type of foulings is that the angle of taught line actually pulls the shaft and engine aft when it wraps around the shaft. You would think it would pull the shaft into the boat. But, the opposite happened. This throws everything out of alignment. It pulled my shaft aft into the rudder and put a hole in it.

I have had the boat at the yard for repairs the past two months. I needed the rudder repaired; new engine mounts; new shaft; prop rebalanced; new dripless shaft seal; new cutlass bearing and the transmission repaired. It has been a bit of an ordeal..

Good luck. You were likely running the engine at a much lower rpm. Hopefully, you will escape this fate.

OMG!!! What an ordeal. Thanks so much for sharing. That's really helpful!
It is definitely humbling to admit it is self-inflicted, but I'm learning so much, and glad it happened in my home port.

[skipgundlach]

BTDT - mooring line, Archimedes at work, jacked the tranny out of the transmission, breaking the bell housing mounting plate in the process...

[fstbttms]

When a synthetic line gets pulled into the bearing housing, heat from friction will frequently turn a portion of the line into a ring of one of the hardest substances know to man. When this happens, nothing short of a hacksaw or hammer and chisel will cut through it. It is possible that you still have some melted line encircling the shaft.

[skipgundlach]

Originally Posted by fstbttms

When a synthetic line gets pulled into the bearing housing, heat from friction will frequently turn a portion of the line into a ring of one of the hardest substances know to man. When this happens, nothing short of a hacksaw or hammer and chisel will cut through it. It is possible that you still have some melted line encircling the shaft.

I once dove on a buddy's boat with exactly that situation.

I wound up going back to our boat and fetching a hammer and utility (not maintained like my wood-use tools) chisel. It came off once I'd split it, but it wasn't moving otherwise, and to try to saw it or otherwise abrade away the surface would have been very difficult not to mention maybe damaging the shaft...

[Tillikum]

If you had a very strong line wound around both shafts and pulled tight between them until your shafts wouldn't turn - effectively making each shaft a sort of windlass pulling against the other, I would suspect you have bent one or both shafts, or perhaps even damaged the bearings and/or skegs.

If neither shaft will rotate freely in neutral as they did before, what else could it be?

You could take the engine & props up to high speed and see if you get vibration and/or noise to confirm this, but at this point a haul out and a straight edge applied to the shafts would be more prudent IMHO. And if the straight edge doesn't do it, next a dial indicator on a fixed base. If your hull is steel a standard magnetic base, if not something else would have to be rigged up.

[skwanderer]

Originally Posted by Tillikum

If you had a very strong line wound around both shafts and pulled tight between them until your shafts wouldn't turn - effectively making each shaft a sort of windlass pulling against the other, I would suspect you have bent one or both shafts, or perhaps even damaged the bearings and/or skegs.

If neither shaft will rotate freely in neutral as they did before, what else could it be?

You could take the engine & props up to high speed and see if you get vibration and/or noise to confirm this, but at this point a haul out and a straight edge applied to the shafts would be more prudent IMHO. And if the straight edge doesn't do it, next a dial indicator on a fixed base. If your hull is steel a standard magnetic base, if not something else would have to be rigged up.

I did motor about for a little bit, running up to full comfortable running speed (1800 rpms) for a few minutes, mainly to see if something was wobbly or out of balance, and I didn't see anything that stuck out to my eyes. Also I felt the area behind/around the stuffing box/shaft log to see if it was warmer/getting hot, and it was getting warmer on the port for sure, not much at all on the starboard shaft (the port prop fouled first, worst and early in the disastrous experience)

As for next steps, will get a diver to examine the shaft, cutlass and strut visually to see if anything looks amiss (can't hold my breathe that long). Also phoning around for haul out availability. As well, getting new gland in the stuffing box.

Thanks for all the shared experiences, outcomes and suggestions! Much appreciated.

[Dooglas]

Originally Posted by tkeithlu

My "most likely" bet is that the line got between the prop and the bearing, and is wrapped very tightly. If that's the case, at most you will have to remove the props and cut away the very tight rope. That's not a disaster, or involve damage to your power train.

I'm with Keith. My first guess would be that a strand or strands of the spring line are wrapped around the shaft and jammed between the prop and the cutlass bearing. Might as well start with the simplest possibility before moving on to damaged cutlass bearing, bent shaft, something pulled out of alignment, etc.

[Mickeyrouse]

I had that happen once with a crab trap toggle. The line got pulled so hard into the bearing that it actually melted the line- under water. I don’t mean fused- melted. Of course, a haul-out was the next order of business, though it probably could have been done by a diver, which I used the NEXT time that happened....