Ramming the lockgates?

[NigelJ]

Bottom gates. No cill. And no rubbish - I looked for that first.

It's far more likely to be rubbish between the cill and the gates.....

 

As I've said. Bottom gates. No cill. Bottom gates are hinged at the top by a large metal (steel?) loop bracketed to the lock wall. I assume the gates are hinged in the same way below the water line, out of sight. I guess the loop/bracket could twist at the join under pressure; a vulnerable spot. more likely than the whole gate twisting.

The problem with this post is that the symptoms that you describe don't actually point to the cause you describe.

 

Lock gates don't have a hinge that can bend, and what you describe sounds like an object that has fallen into the lock and is preventing the gate from sealing against the cill

 

Bottom gates. No cill. See my other replies.

It is possible the gate had twisted, from memory Middlewich Three have composite gates, which most peiople would call steel gates as they are steel except for the heel post and the mitre post. The metal bit can (and does) sometimes bend, which is why BW don't use them so much anymore

 

However, debris on cill is more likely

[NigelJ]

Ok guys and gals. Last word from me on this. I was only theorising about the bent hinge but I do know the difference between top gate and bottom gates. I said 'bottom gates'. So why all the references to a cill, and stuck debris, when bottom gates don't have cills? I'm no canal engineer but after maybe 1,000 + locks (and, no, I've not counted them) in the last 3+ years, I've never encountered this particular problem of the tops of the bottom gates sealing tight but with a large (8-inch, till me+water pressure forced it to 2-inch) gap at the bottom. Not just a leaky gate. And might not be bent hinge; might be something stuck under one of the bottom gates - very unusual and I couldn't feel any obstruction. So I told BW as I doubt it would correct itself.

 

And also, what's all this clever talk of nosing up to the bottom gates of an empty lock, and managing the current and all that? Who's in so much of a hurry that they can't tie up at the bollards/rings and wait for the lock to empty? if you're that impatient, take up motor racing instead

 

PS I'll see if I can find out from BW what the lockgate problem was. If I'm wrong, no problem, I'll have learned something either way.

[RLWP]

Nigel, all gates have a cill to close against, otherwise what stops the water leaking out? At the bottom of the bottom gate it is a step about four to six inches high. The gate closes against this to seal itself. As I said earlier the hinge at the base of the gate is a simple pin working in a socket in the gate. It isn't the same as the top strap.

 

I spent a happy fifteen minutes getting a sunken bit of wood out from between the cill and the bottom gate by Yarningdale common once.

 

Richard

 

More: Here's a mitred bottom gate on the Wey and Arun:

Edited January 12, 2011 by RLWP

[blodger]

Ok guys and gals. Last word from me on this. I was only theorising about the bent hinge but I do know the difference between top gate and bottom gates. I said 'bottom gates'. So why all the references to a cill, and stuck debris, when bottom gates don't have cills? I'm no canal engineer but after maybe 1,000 + locks (and, no, I've not counted them) in the last 3+ years, I've never encountered this particular problem of the tops of the bottom gates sealing tight but with a large (8-inch, till me+water pressure forced it to 2-inch) gap at the bottom. Not just a leaky gate. And might not be bent hinge; might be something stuck under one of the bottom gates - very unusual and I couldn't feel any obstruction. So I told BW as I doubt it would correct itself.

 

And also, what's all this clever talk of nosing up to the bottom gates of an empty lock, and managing the current and all that? Who's in so much of a hurry that they can't tie up at the bollards/rings and wait for the lock to empty? if you're that impatient, take up motor racing instead

PS I'll see if I can find out from BW what the lockgate problem was. If I'm wrong, no problem, I'll have learned something either way.

It's not so much about speed but efficacy and emulating the working boatmen of yesteryear for whom the canal was built and whose working practice cannot be bettered by today's weekend boaters/gin pallaces

[Hairy-Neil]

As I said earlier the hinge at the base of the gate is a simple pin working in a socket in the gate.

 

Or the opposite. The Slea Navigation locks have a large iron socket let into the wooden cill structure

[ymu]

I said 'bottom gates'. So why all the references to a cill, and stuck debris, when bottom gates don't have cills?

Bottom gates do have cills, they're just outside the lock so you never need to worry about them.

[mayalld]

Bottom gates. No cill. And no rubbish - I looked for that first.

 

 

As I've said. Bottom gates. No cill. Bottom gates are hinged at the top by a large metal (steel?) loop bracketed to the lock wall. I assume the gates are hinged in the same way below the water line, out of sight. I guess the loop/bracket could twist at the join under pressure; a vulnerable spot. more likely than the whole gate twisting.

 

 

Bottom gates. No cill. See my other replies.

 

 

Saying it 3 times doesn't change the fact that bottom gates DO nave a cill.

 

If they didn't, water would simply escape under the gate.

 

You say "no rubbish", but how on earth do you know that? The rubbish that we are talking about is 4 feet under water, on the cill.

 

Finally, your assumpions about how the gates are hinged is quite simply wrong. the bottom end of the heel post is fitted with a "pintle" (a short iron shaft, sticking out of the bottom) that sits in an iron cup that is bonded to the masonry.

[Chris Pink]

Saying it 3 times doesn't change the fact that bottom gates DO nave a cill.

 

 

That's twice in two days I've agreed with you Dave. Please stop talking sense at once, it's all too strange for words.

 

 

It's OK, i see you're talking your usual crap about licences elsewhere.

 

Normality is assured.

[Mrs Tawny Owl]

It's possible that the gate had been lifted slightly, and on settling back didn't stand correctly on the pintle, or socket when it went back down.

 

This might well give the symptoms you mention as the bottom pivot would not be in the correct place. I now wait for those that know to tell me why this suggestion is wrong.

 

I've had trouble shutting a bottom gate on the Stratford, though it was upright, not tipped over, and the only way it would close was to bounce on the balance beam. It then seemed to settle properly and closed, so again something had got slightly out of true, or there was rubbish under it.

 

Sue

[NigelJ]

Okay okay. Mea culpa. You all know more about lock construction than I do and I'm happy to learn. Of course, if I'd thought about it, there has to be some kind of a cill under the bottom gates for them to seal at the base of the lock. And I appreciate being enlightened about the 'pindle' holding the bottom of the gate.

 

What concerned me on this occasion (last week) was the way the gate not only got nowhere near closing but swung back open. This usually happens when the gate balance has been distorted, leading me to guess either the top hinge or the bottom pindle (now that I know what that is) had been slightly bent. One can usually 'feel' an obstruction like rubbish or wood against a gate, even when it's under water. However, it might have been a chunk of submerged wood jammed agains the lock wall.

 

Anyway, I'll see if I can find out from BW what was wrong with it: gate gear, rubbish or whatever. I'm not at all interested in whether I'm 'right' or 'wrong' and I'll let you know what was the cause if I can.

 

Oh and thanks for the illustration, Richard. I looked for something like that via Google but nothing came up.

[alan_fincher]

Bottom gates. No cill. And no rubbish - I looked for that first.

 

 

As I've said. Bottom gates. No cill. Bottom gates are hinged at the top by a large metal (steel?) loop bracketed to the lock wall. I assume the gates are hinged in the same way below the water line, out of sight. I guess the loop/bracket could twist at the join under pressure; a vulnerable spot. more likely than the whole gate twisting.

 

 

Bottom gates. No cill. See my other replies.

If you think you have found a pair of bottom gates with no cill, please explain why, if you swing them closed, they come to an abrupt stop when the leading edge reaches the middle of the lock.

 

What do you think stops that first gate in it's tracks, rather than it just continuing to swing right round ?

 

The reason you can go no further is because there most definitely always IS a cill!

[RLWP]

<snip>

 

Oh and thanks for the illustration, Richard. I looked for something like that via Google but nothing came up.

 

No problem. It took me bloody ages to find a picture, and I still haven't found an illustration of the pintle and cup for you

 

Richard

[mayalld]

Okay okay. Mea culpa. You all know more about lock construction than I do and I'm happy to learn. Of course, if I'd thought about it, there has to be some kind of a cill under the bottom gates for them to seal at the base of the lock. And I appreciate being enlightened about the 'pindle' holding the bottom of the gate.

 

What concerned me on this occasion (last week) was the way the gate not only got nowhere near closing but swung back open. This usually happens when the gate balance has been distorted, leading me to guess either the top hinge or the bottom pindle (now that I know what that is) had been slightly bent. One can usually 'feel' an obstruction like rubbish or wood against a gate, even when it's under water. However, it might have been a chunk of submerged wood jammed agains the lock wall.

 

Two possibilities;

 

1. something resting on the cill that the base of the gate is riding up on, with the weight of the gate causing it to open as it falls back (think rising butt hinge)
2. Some gates on the T&M have a tendency to fall open, due to subsidence affecting the vertical alignment of the chamber.

[mayalld]

No problem. It took me bloody ages to find a picture, and I still haven't found an illustration of the pintle and cup for you

 

Richard

 

Tricky isn't it!

 

(just) shows a pintle at the extreme left.

[RLWP]

Tricky isn't it!

 

(just) shows a pintle at the extreme left.

 

Interesting. So that's a gate mounted pintle working in a socket like Hairy-Neil described for the Slea navigation

 

Richard

[mayalld]

Interesting. So that's a gate mounted pintle working in a socket like Hairy-Neil described for the Slea navigation

 

Richard

 

Yes.

 

I believe that these are the most common type.

[RLWP]

Yes.

 

I believe that these are the most common type.

 

I don't have enough experience of the bottom of lock gates to know. I'm pretty sure I've seen pictures of a cast iron pintle mounted into the cill that works in a cast iron socket in the gate. But as I said, I'm not an expert.

 

Richard

[NB Alton]

And also, what's all this clever talk of nosing up to the bottom gates of an empty lock, and managing the current and all that? Who's in so much of a hurry that they can't tie up at the bollards/rings and wait for the lock to empty? if you're that impatient, take up motor racing instead

 

It's not clever talk, this is a legitimate & traditional method of boating. It is not about being impatient, but as Blodger says it is about working efficiently & effectively. I do plenty of boating singlehanded with a deep draughted boat. If I was to tie up at the bollards at each lock I would spend a lot of time stuck on the bottom as many of these locations do not have sufficient depth. It is just a waste of time & energy to tie-up at each lock. The boat will happily sit with its fender resting on the lock gate, whilst I set the lock. This causes no damage to the lock gate or boat. Maybe you should try it some time, you might find it easier.

[RLWP]

It's not clever talk, this is a legitimate & traditional method of boating. It is not about being impatient, but as Blodger says it is about working efficiently & effectively. I do plenty of boating singlehanded with a deep draughted boat. If I was to tie up at the bollards at each lock I would spend a lot of time stuck on the bottom as many of these locations do not have sufficient depth. It is just a waste of time & energy to tie-up at each lock. The boat will happily sit with its fender resting on the lock gate, whilst I set the lock. This causes no damage to the lock gate or boat. Maybe you should try it some time, you might find it easier.

 

Helps if you have a good bow fender of course...

 

Richard

[mayalld]

 

And also, what's all this clever talk of nosing up to the bottom gates of an empty lock, and managing the current and all that? Who's in so much of a hurry that they can't tie up at the bollards/rings and wait for the lock to empty? if you're that impatient, take up motor racing instead

 

 

Put bluntly, it isn't about rushing around, it is about efficiency in working through a bottleneck.

 

In many parts of the system, there are a lot of people trying to pass through a lock on any given day. If it takes 15 minutes to transit a lock, no more that 4 boats per hour can do it. Get it down to 10 minutes, and 6 boats per hour. If you can reach the holy grail of 5 minutes per lockage, 12 boats per hour could pass.

 

People who tie up to bollards when they could avoid doing so will occupy the lock for longer than is necessary.

[Nine of Hearts]

Put bluntly, it isn't about rushing around, it is about efficiency in working through a bottleneck.

 

I don't even think it's that. For me it's not the time elapsed, it's the effort (especially as I single hand such a lot). Should be one for the oxymoron thread that those people who argue for a more relaxed approach take such issue with those who wish to make things easier...

[NB Alton]

Helps if you have a good bow fender of course...

 

Richard

Yes, but if you want to know how to make a good one, just attend my course .

 

Whoops I'm preaching to the converted with you Richard!

[mykaskin]

There are many gates on the system which don't stay shut when closed due to various reasons. Often the only way to navigate these locks single handed is to open a top paddle to hold the gate shut.

 

The reason there might be a gap when closed could be down to a few factors, but if it wasn't debris then the gate may have warped/twisted so it is no longer square and therefore meeting at the top before the bottoms do. The presure of the water will twist the gate back against the cill and other gate performing a seal which can be just as good as a none warped gate. I assume you didn't need the boat to bump open the top gate so the leakage can't have been too bad once filled.

 

There are many times when it is safer to put the boat in the lock mouth when possible to hold the boat in place. It is not nesseserily down to impatience, and if I want to cover a large amount of distance I am allowed too just as you are allowed to travel at your own pace.

 

Cheers,

 

Mike

[mayalld]

I don't even think it's that. For me it's not the time elapsed, it's the effort (especially as I single hand such a lot). Should be one for the oxymoron thread that those people who argue for a more relaxed approach take such issue with those who wish to make things easier...

 

Very true.

 

There are many reasons why one might wish to operate a lock efficiently.

[Guest]

There are many gates on the system which don't stay shut when closed due to various reasons. Often the only way to navigate these locks single handed is to open a top paddle to hold the gate shut.

 

Mike

 

Do you mean single handedly operating the lock?

 

I struggle to keep some of them on the T&M shut and find often the only way to do it is to open a paddle at the other end, (the one at Alweras is a right barsteward for it) is there a better way if somebody is on the boat too?

 

Just curious.

 

 

..

Edited January 12, 2011 by MJG