First breakdown

[bluelapsing]

Hi guys, 

 

At the end of an eventful two days on our first trip from Church Minshull we’re happily moored at the top of the Audlem Flight. 
 

The engine, unfortunately, is not so happy. The tiller locked and acceleration vanished with no apparent cause coming through lock 9/10. We’ve had a look in the weed hatch and from behind the boat and nothing’s wrapped up in there. We were lucky enough to be 100m away from a couple who had a look and suspect there’s an issue with the prop shaft coupling mechanism. 
 

I’ve attached a picture, which probably won’t be of much use, but has anybody experienced anything similar/have any ideas/advice for if we’re not able to get it running in the morning? 
 

Many grateful thanks in advance 🤞❤️
 

 

[alan_fincher]

With the engine not running, and neutral selected on the gearbox, can you turn the propshaft (and hence the prop) by hand?  If the stern gland is sensibly packed and tightened it should be quite easy to manually rotate the prop shaft.

[nicknorman]

Tiller locked - could the prop shaft have moved back so that it’s hitting the front of the rudder?

[ditchcrawler]

Had you just been in reverse by any chance, rudder locked and no drive indicated the shaft and prop have slipped in the coupling and are fouling the rudder.

 

[bluelapsing]

1 minute ago, alan_fincher said:

With the engine not running, and neutral selected on the gearbox, can you turn the propshaft (and hence the prop) by hand?  If the stern gland is sensibly packed and tightened it should be quite easy to manually rotate the prop shaft.

We can now, but only after a bit of poking around. The tiller was refusing to turn to the right full-stop, but now steering is restored and there doesn’t seem to be a major issue with the prop itself after digging around. 
 

The other concern we want to allay/monitor/maybe fix is the possibility of the same thing happening again once we go into reverse again, as that seemed to be when it all went horribly wrong…

 

 

3 minutes ago, ditchcrawler said:

Had you just been in reverse by any chance, rudder locked and no drive indicated the shaft and prop have slipped in the coupling and are fouling the rudder.

 

 

Yes!!!

6 minutes ago, nicknorman said:

Tiller locked - could the prop shaft have moved back so that it’s hitting the front of the rudder?

This sounds like an accurate diagnosis of the problem.
 

Is there a relatively quick and painless solution, or would we be best advised to prepare for a prolonged stay? 😩

[agg221]

To reiterate and slightly expand on Alan's comment above. With the engine switched off and the gearbox in neutral, if you open up the weed hatch and turn the prop by hand, what can you see rotating? If everything rotates back to and including the shaft into the gearbox then nothing has sheared right off. If you then try putting it into gear in forwards and try the same thing, does it get really difficult to turn? If so, can you see the flywheel on the engine moving (you are not trying to turn it over, just check everything is solidly locked together and moves in the right direction)? Then try the same again in reverse. If everything works then you should have drive in forwards and reverse.

 

Next, I would CLOSE THE WEEDHATCH and start the engine and, with the deck boards up so you can see what happens, try engaging first forwards and then reverse and see if everything is OK. Watch for whether everything is rotating as it should, and whether anything moves forwards or backwards (engine on its mounts, or the shaft relative to the gearbox). If yes, you have an indication of where the problem lies, if no then for now everything is OK.

 

At that point I would carry on, taking it gently. I would engage reverse early and aim to stop just inside the bottom gates, as you have plenty of space then for the boat to stop if you lose reverse. You don't have too many more locks to go for a while, so if it works in forwards you should be able to get to somewhere that someone can take a look at it. The centre of Market Drayton is not too far and once you are up Adderley you won't need reverse again for a while.

Alec

 

 

[springy]

Looking down the weed hatch how close is the prop to the rudder/how big is the gap between the prop and the end of the stern tube - if the shaft has moved outwards there may be an obvious line visible on the shaft indicating its normal position. Similarly the inner end of the shaft may have an obvious line where it went into the clamp. Are the four clamp bolts tight ?  Does the shaft have a lot of visible keyway at the clamp end ? (rotate the shaft to check) If so its also possible that the key has dropped out though it may be still inside the coupling. If the key is still there and there is more than a couple of inches between the prop and the stern tube, loosening the clamp bolts may allow you to push the shaft back into the clamp and re tighten the clamp bolts.

 

springy

[nicknorman]

10 hours ago, bluelapsing said:

We can now, but only after a bit of poking around. The tiller was refusing to turn to the right full-stop, but now steering is restored and there doesn’t seem to be a major issue with the prop itself after digging around. 
 

The other concern we want to allay/monitor/maybe fix is the possibility of the same thing happening again once we go into reverse again, as that seemed to be when it all went horribly wrong…

 

 

 

Yes!!!

This sounds like an accurate diagnosis of the problem.
 

Is there a relatively quick and painless solution, or would we be best advised to prepare for a prolonged stay? 😩

from the picture it looks like the prop shaft is clamped by 4 bolts - the 4 bolts to the right of the coupling. Check they are tight. If not, slacken until you can push the prop shaft fully in, then tighten evenly.

 

If they do seem tight then it would be worth checking the diagnosis by putting boat into fwds and then reverse and seeing if there is any axial movement of the prop shaft - it has some different colouring (gold/silver/black) to help that. And I suppose check that the entire engine /gearbox isn’t moving fwds and backwards -which would indicate broken engine mounts (unlikely). And of course check that the prop shaft is actually rotating when in gear.

 

If it is moving axially even though the bolts are tight then you would need to undo it and wrap some very thin shim stock around the prop shaft in the area of the clamp, so that the clamp bolted up tight to the prop shaft.

[Bod]

One item not mentioned, is the propellor firmly fixed to the shalf?

Engine stopped, gearbox in neutral, weedhatch open, reach down touching the propellor, feel right down the blades to the centre, there should be a hexagon nut with a split pin through to secure the nut.

You are checking to ensure both these are present, and not loose.

[Tracy D'arth]

It could also be that you have unshipped the rudder from the bottom cup and it has moved forward into the prop.

[Tony Brooks]

2 minutes ago, Tracy D'arth said:

It could also be that you have unshipped the rudder from the bottom cup and it has moved forward into the prop.

 

Especially as the markings on the shaft by the flange clamp and gland show no real signs of it moving back far enough for the prop to hit the rudder.

[nicknorman]

17 minutes ago, Tony Brooks said:

 

Especially as the markings on the shaft by the flange clamp and gland show no real signs of it moving back far enough for the prop to hit the rudder.

It certainly looks as though the prop shaft was more or less fully home when the photo was taken, but this was after some “poking around” which freed the rudder, and then use of fwd gear (AIUI), so I thought it worth checking that the coupling wasn’t slipping and shaft pulling out in reverse gear (which is when the problem arose).

[bluelapsing]

Morning all, 

 

Happily we bumped into (read “knocked on the window of”) a marine engineer last night who’s kindly taking a stab at it right now. 
 

The rudder and the bottom cup are fine and he thinks the issue isn’t drastic. The root cause seems to be a worn part (image attached) which he found after unscrewing a big yellow disc…

 

I did read him all your messages and after a good half hour of poking around he’s hopeful that it might start soon!! 
 

Thanks for all the detailed help 🤝

[Tony Brooks]

1 minute ago, nicknorman said:

It certainly looks as though the prop shaft was more or less fully home when the photo was taken, but this was after some “poking around” which freed the rudder, and then use of fwd gear (AIUI), so I thought it worth checking that the coupling wasn’t slipping and shaft pulling out in reverse gear (which is when the problem arose).

 

I agree, well worth checking, but if the shaft had slid back, but is now back in place. I would expect to see signs of the shaft sliding in front of the gland, with the dirt/grease scraped off to a degree.

1 minute ago, bluelapsing said:

Morning all, 

 

Happily we bumped into (read “knocked on the window of”) a marine engineer last night who’s kindly taking a stab at it right now. 
 

The rudder and the bottom cup are fine and he thinks the issue isn’t drastic. The root cause seems to be a worn part (image attached) which he found after unscrewing a big yellow disc…

 

I did read him all your messages and after a good half hour of poking around he’s hopeful that it might start soon!! 
 

Thanks for all the detailed help 🤝

 

Looking back at the original photo that makes sense, you can see a polished section on the shank of that part that suggest it has been moving back and forth. Hopefully, just the big nut holding onto the gearbox shaft has come loose.

[Tracy D'arth]

Missed that in the photo.  I should have seen it.

You can plainly see that the drive flange has pulled out of the gearbox. There is no thrust plumbers block bearing on the prop shaft so the gearbox is taking all the thrust and the reverse in reverse gear. 

Unusual for the nut on the shaft to come undone.

[Tony Brooks]

11 hours ago, Tracy D'arth said:

Missed that in the photo.  I should have seen it

 

That makes two of us, yes, very unusual.

[robtheplod]

Fantastic forum, love how many people want to help....

[bluelapsing]

Morning all,

 

Massive stroke of good luck on our part, and huge amount of skill and experience and kindness on Darryl and Valerie’s end, meant me were able to get up and running by midday and haven’t had any mechanical problems since!!

 

We’ve made it to Norbury Junction now and will definitely stop for a little while to get the engine properly looked at. It did get mentioned in the survey that the engine could do with a service as there was something loose causing it to vibrate more than usual, but the surveyor was quite sure it would be fine for the initial journey. Darryl also thought it was odd that the nut should come loose as and when it did and said it could be fine forever now, but having stared down the barrel once we’re going to take his advice and get a professional opinion before we carry on. 
 

Time to soak up some sun and wi-fi and phone signal for now - enjoy the weather all and thanks again 🙏 

[Iain_S]

18 hours ago, Tracy D'arth said:

Missed that in the photo.  I should have seen it.

You can plainly see that the drive flange has pulled out of the gearbox. There is no thrust plumbers block bearing on the prop shaft so the gearbox is taking all the thrust and the reverse in reverse gear. 

Unusual for the nut on the shaft to come undone.

 

6 hours ago, Tony Brooks said:

 

That makes two of us, yes, very unusual.

Ours did, when reversing out of the moorings in Manchester. Bit embarrassing, as we had to get RCR in, because I didn’t have a socket to fit. Our nut was supposed to be secured by peening onto a flat on the shaft, which was near impossible with the gearbox in place. Now tight, but I’ll need to get it off sometime, as there is now an annoying gearbox oil leak from the rear seal.