Another cilling on the Middlewich Branch (Cholmondeston Lock)

[Theo]

Notice Alert

Middlewich Branch (Shrop Union Canal)

Starts At: Lock 4, Cholmondeston Lock

Ends At: Lock 4, Cholmondeston Lock

Up Stream Winding Hole: North of Benion’s Bridge No 4

Down Stream Winding Hole: Sykes Hollow North of bridge No 5a

Thursday 25 February 2016 14:00 until further notice

Type: Navigation Closure

Reason: Boat damage

Original message:

Navigation closed due to craft hung up in the lock chamber. Contractors to attend site today. Further updates will follow when available.

You can view this notice and its map online here:

https://canalrivertrust.org.uk/notice/6691/boat-sunk-at-cholmondeston-lock-middlewich-branch

You can find all notices at the url below:

https://canalrivertrust.org.uk/notices

Sad for someone. I hope that no one was hurt.

Nick

[Paul C]

At least there's good road access (to get equipment in, etc).

Edited February 25, 2016 by Paul C

[junior]

I was there earlier. Nobody hurt. Lovely couple, very sad but taking it well.

 

Commercial Boat Services on site now and I expect it'll be reopened in the morning.

[Theo]

Private or hire boat?

[junior]

Private or hire boat?

Private.

[Guest]

I was there earlier. Nobody hurt. Lovely couple, very sad but taking it well.

Commercial Boat Services on site now and I expect it'll be reopened in the morning.

Any insight on what actually happened?

[WotEver]

Any insight on what actually happened?

Well you see, on every lock the uphill gates have this big lump of concrete....

 

:::coat:::

[Guest]

Well you see, on every lock the uphill gates have this big lump of concrete....

 

:::coat:::

Chortle....

[frangar]

Well you see, on every lock the uphill gates have this big lump of concrete....

:::coat:::

It's easy to be flippant.......

 

Even those of us who have boated for quite a while can't say we haven't had the odd close shave....I know I have....it's quite sobering how quickly things can go wrong and escalate.

 

Please don't make fun of someone else's misfortune....,one day it might be you!

 

Gareth

[dor]

Lock now cleared.

[Guest]

frangar, on 26 Feb 2016 - 12:21 PM, said:

It's easy to be flippant.......

 

Even those of us who have boated for quite a while can't say we haven't had the odd close shave....I know I have....it's quite sobering how quickly things can go wrong and escalate.

 

Please don't make fun of someone else's misfortune....,one day it might be you!

 

Gareth

 

I think that perhaps was more aimed at me asking what might on the face of it be a very obvious question.

 

I was curious though how such an event can happen as unless your boat is particularly long I find it intriguing how this type of accident happens. It must be down to getting distracted in most cases or in rarer ones some sudden failure that empties the lock much quicker than was expected.

 

What ever the cause it's still interesting to know,

[Guest]

Sorry to hear this, a real shame for the owners. Hope damage is minimal. There but for fortune....

[Guest]

catweasel, on 26 Feb 2016 - 1:18 PM, said:

Sorry to hear this, a real shame for the owners. Hope damage is minimal. There but for fortune....

 

yes I should have appended this to my post.

[WotEver]

Please don't make fun of someone else's misfortune....

I wasn't. If you take the time to look at my quote you would see that I was making fun of Martin's question.

 

Tony

[Keeping Up]

I was curious though how such an event can happen as unless your boat is particularly long I find it intriguing how this type of accident happens. It must be down to getting distracted in most cases or in rarer ones some sudden failure that empties the lock much quicker than was expected.

 

One possibiilty that can make this happen, is that some locks will occasionally defy logic and draw the boat back towards the top gates when a bottom paddle is opened - in much the same way that opening a top paddle will draw the boat forwards to the top gate. It's not that common but I've experienced it a few times, particularly on deep narrow locks (such as this one is). One of the locks around the corner from there at Hurleston does it quite frequently if you have a longish boat. The stern is then above the cill as the lock starts to empty, and it is surprising how quickly it can turn into a potential disaster because at that point the lock is emptying very rapidly; it caught me out that way a few years back and by the time I had dropped both the bottom paddles the front cockpit was only inches above the waterline.

 

Of course I don't know if that is what happened here, but it is a possibility

[mrsmelly]

I hope it never happens to me. Funnily enough I think having a longer or full length narrowboat probably is the safer bet as you are always on the look out due to the obvious dangers of less room for fault. On a tiddly boat say 60 foot downwards the margin for error is far greater and its easier to become complacent.

 

Tim

[Paul C]

 

One possibiilty that can make this happen, is that some locks will occasionally defy logic and draw the boat back towards the top gates when a bottom paddle is opened - in much the same way that opening a top paddle will draw the boat forwards to the top gate. It's not that common but I've experienced it a few times, particularly on deep narrow locks (such as this one is). One of the locks around the corner from there at Hurleston does it quite frequently if you have a longish boat. The stern is then above the cill as the lock starts to empty, and it is surprising how quickly it can turn into a potential disaster because at that point the lock is emptying very rapidly; it caught me out that way a few years back and by the time I had dropped both the bottom paddles the front cockpit was only inches above the waterline.

 

Of course I don't know if that is what happened here, but it is a possibility

 

Cholmendeston Lock is completely normal and the water flows/forces behave completely normally. The only notable thing is its over 11' deep - but that in itself is no reason to cause a cilling.

[alan_fincher]

 

Cholmendeston Lock is completely normal and the water flows/forces behave completely normally. The only notable thing is its over 11' deep - but that in itself is no reason to cause a cilling.

 

That does not accord entirely with quite a few people who have reported that there are strong draws backwards and forwards in that lock, (though obviously that would more apply to filling it than emptying it, which would have been the case if this really is a "cilling").

 

Strong draws are reported when filling locks on the Middlewich branch, Wardle lock, in particular, being often quoted for it. I didn't really believe this until we were drawn very rapidly forward in the filling lock at Wardle.

 

Howevver, one of the recent sinkings in Chelmondeston lock appears to have related to the cill, but not been a cilling. It appears to have related to a boat coming up in the lock (rather than descending) and having had its stem held down by getting trapped under a wooden part of the cill.

 

In general it always seems to me that cillings should be rarer in narrow locks like these with small cills, as opposed to say a typical GU lock, simply because there is so much less cill to end up on. It doesn't seem to stop it happening though!

[Paul C]

 

That does not accord entirely with quite a few people who have reported that there are strong draws backwards and forwards in that lock, (though obviously that would more apply to filling it than emptying it, which would have been the case if this really is a "cilling").

 

Strong draws are reported when filling locks on the Middlewich branch, Wardle lock, in particular, being often quoted for it. I didn't really believe this until we were drawn very rapidly forward in the filling lock at Wardle.

 

Howevver, one of the recent sinkings in Chelmondeston lock appears to have related to the cill, but not been a cilling. It appears to have related to a boat coming up in the lock (rather than descending) and having had its stem held down by getting trapped under a wooden part of the cill.

 

In general it always seems to me that cillings should be rarer in narrow locks like these with small cills, as opposed to say a typical GU lock, simply because there is so much less cill to end up on. It doesn't seem to stop it happening though!

 

I'd attribute the strong flows entirely to its depth (strictly, the drop/rise) due to the forces of the water due to the head (pressure difference of water due to its difference in height).

 

I can offer an explanation of the cill interaction. Last year, an incident occurred where a boat entered the lock (going uphill) and struck the cill hard instead of slowing down. It loosened it, and soon after the cill buffer completely detached. I don't know how long in between the two events occured, but the cill buffer was quite worn/smashed up anyway, and was loose for a period of time. I think they "tried" a quick fix too for a while, to get the lock more/less running again (its a pain to do singlehanded with no cill buffer!) but it didn't work and they had to fix it properly.

 

ETA all the locks on the Middlewich branch are deeper than average, if that makes sense. Without looking them up, I think Wardle is about 9'9" and the others all 11'+, my memory escapes me but one of them is 11'11" and Cholmendeston is 11'3".

Edited February 26, 2016 by Paul C

[Guest]

The late Maureen always used to warn about Wardle lock, and the effect of drawing the boat towards the gates.

[Theo]

 

One possibiilty that can make this happen, is that some locks will occasionally defy logic and draw the boat back towards the top gates when a bottom paddle is opened - in much the same way that opening a top paddle will draw the boat forwards to the top gate. It's not that common but I've experienced it a few times, particularly on deep narrow locks (such as this one is). One of the locks around the corner from there at Hurleston does it quite frequently if you have a longish boat. The stern is then above the cill as the lock starts to empty, and it is surprising how quickly it can turn into a potential disaster because at that point the lock is emptying very rapidly; it caught me out that way a few years back and by the time I had dropped both the bottom paddles the front cockpit was only inches above the waterline.

 

Of course I don't know if that is what happened here, but it is a possibility

 

Not at all sure if that defies logic. Water being drawn off at the bottom means that there could easily be a vertical circulation set up:

 

1. A layer of water at the bottom of the gate moves forward out of the paddles.

2. Water towards the top gates moves down to replace the water moving forward out of the paddles.

3. Water at the top moves back to replace the water moving down.

 

Nick

[Paul C]

I suppose certain locks can defy logic, but none of them defy the laws of physics.

[WotEver]

I suppose certain locks can defy logic, but none of them defy the laws of physics.

However, understanding exactly how those laws are performing in a specific environment at any one time can be pretty elusive.

 

Tony

[MtB]

The late Maureen always used to warn about Wardle lock, and the effect of drawing the boat towards the gates.

 

 

I've only done Maureen's lock once, and the thing that struck me was all the stress and bad temper going on there, as other boaters tried to hurry us through.

 

It's not as though we were being slow, more that we were not quite as fast as the military thought we ought to have been, there only being two of us....

[Paul C]

I think they did a crude mod recently to Wardle lock, by setting some kind of stop so the top paddles can only be 3/4 opened?