Missing paddles.

[Laurence Hogg]

I well remember the T&M paddles which emptied one lock into the other one in the pairs on heartbreak hill, they worked a treat saving a lot of water. The GU ones certainly worked well too (back in the 1970's).

The culverts are still there in most cases and some of the framework so reinstating them would be possible. Using sideponds should be mandatory where they exist as operable, perhaphs its time CRT "woke up" to reinstating that which saves water. As for the poor poster on here that thinks they do not work or save the amount they do peraphs he should be at the front of the queue for re education!

I dont think the GUCCo would have wasted their money on things that didnt help do what they wanted!

[Pluto]

Pluto, Marple is a conundrum, and for a flight I walk almost every day at the moment, it still holds riddles.

Hi Magpie, perhaps I can come over and have a walk down the flight with you. Nothing better than a discussion on site. On the French plan, some of the foreign descriptions do have discrepancies as they sometimes seem to rely upon hearsay. However, I put it up because it is one of very few contemporary drawings of paddle gear. Such foreign drawings can be reliable, as the Prussian ones I have for the mine canal in Zabrze, Upper Silesia, matches exactly the few descriptions of Worsley, on which it was based, made by workers in the mines.

[magpie patrick]

Hi Magpie, perhaps I can come over and have a walk down the flight with you. Nothing better than a discussion on site.

 

Nothing better or more sociable: PM sent

[tarboat]

As for the poor poster on here that thinks they do not work or save the amount they do peraphs he should be at the front of the queue for re education!

I dont think the GUCCo would have wasted their money on things that didnt help do what they wanted!

Were you referring to my comments Laurence? I stand by my statement that it is not possible for a sidepond to save 50% of water in a lock. I did not say that side ponds do not work, just that the amount saved is more like a third rather than a half. If you can prove otherwise I shall be pleased to see your explanation. 50% is possible when emptying directly from one lock to another alongside.

 

Cheers,

[magpie patrick]

Were you referring to my comments Laurence? I stand by my statement that it is not possible for a sidepond to save 50% of water in a lock. I did not say that side ponds do not work, just that the amount saved is more like a third rather than a half. If you can prove otherwise I shall be pleased to see your explanation. 50% is possible when emptying directly from one lock to another alongside.

 

Cheers,

Indeed, to save 50% with only one sidepond it would need to be infinite in area. It will be around a third if the side pond has the same area as the lock.

 

Split sideponds can save more so long as they are big enough. On the Rhine-Main-Danube locks three sideponds save 60% of the water, but they are each about the same area as the lock.

 

TBH, water wastage is a much bigger issue these days, leakage, paddles left open etc. If the canals only used that which was lost in lock operation there'd be less of a problem.

[Laurence Hogg]

Were you referring to my comments Laurence? I stand by my statement that it is not possible for a sidepond to save 50% of water in a lock. I did not say that side ponds do not work, just that the amount saved is more like a third rather than a half. If you can prove otherwise I shall be pleased to see your explanation. 50% is possible when emptying directly from one lock to another alongside.

 

Cheers,

Yes I was, but you have answered your own question in the above, what is the difference between a side pond and a adjacent lock? The side ponds as built were to hold the max quantity that would pass int them, do you not think that GUCCo engineers could not do their maths? Take a good look at Knowle locks or look up the engineering spec for them, the quantities are all there.

When those side ponds worked you emptied them in operation, not leaving water in them at all.

Edited August 29, 2013 by Laurence Hogg

[RLWP]

Take a good look at Knowle locks

 

You usually get a great opportunity while trying to recover from the tricky cross winds there

 

Knowle locks are actually a very neat bit of engineering. Not surprising really as they must be last seriously engineered lock flight designed

 

Richard

[tarboat]

Yes I was, but you have answered your own question in the above, what is the difference between a side pond and a adjacent lock? The side ponds as built were to hold the max quantity that would pass int them, do you not think that GUCCo engineers could not do their maths?

I don't understand what you are getting at in the above questions. I never suggested that the GU engineers could not do their maths. My original post was in response to another poster who stated that a sidepond would save 50% of the water in a lock.. If you pass the water directly from one lock into one alongside (as was once practised on the T&M on Cheshire Locks) you will be able to save 50% of the water. If you pass the water into a sidepond to store it before using it again in the lock, then you will save a lesser amount, which in typical cases is about a third. The only way to save more water is to use multiple sideponds at different levels as pointed out by Magpie Patrick above.

Edited August 29, 2013 by tarboat

[magpie patrick]

Yes I was, but you have answered your own question in the above, what is the difference between a side pond and a adjacent lock? The side ponds as built were to hold the max quantity that would pass int them, do you not think that GUCCo engineers could not do their maths? Take a good look at Knowle locks or look up the engineering spec for them, the quantities are all there.

When those side ponds worked you emptied them in operation, not leaving water in them at all.

 

There is one very big difference, a boat can go through an adjacent lock but not through a side pond, and that's why interconnecting paddles are so efficient: an ascending boat gets its lock half filled by the descending boat. Or alternatively a following boat finds one lock already half full (or half empty) and uses less water to set the lock.

 

This idea wasn't so efficient that companies built parallel locks just to save water though.

[Laurence Hogg]

I don't understand what you are getting at in the above questions. I never suggested that the GU engineers could not do their maths. My original post was in response to another poster who stated that a sidepond would save 50% of the water in a lock.. If you pass the water directly from one lock into one alongside (as was once practised on the T&M on Cheshire Locks) you will be able to save 50% of the water. If you pass the water into a sidepond to store it before using it again in the lock, then you will save a lesser amount, which in typical cases is about a third. The only way to save more water is to use multiple sideponds at different levels as pointed out by Magpie Patrick above.

 

Its obvious you have never used GU side ponds. the ones at Knowle are huge and used to empty completely into the chamber, there was as far as I can see no water loss if a boater used both, your argument doesnt make sense. Have you ever used a side pond?

[tarboat]

 

Its obvious you have never used GU side ponds. the ones at Knowle are huge and used to empty completely into the chamber, there was as far as I can see no water loss if a boater used both, your argument doesnt make sense. Have you ever used a side pond?

Yes, I have used a sidepond, thank you. GU or not It is not physically possible to empty a lock into a sidepond and then use that sidepond to refill said lock by 50%. You would have to have a sidepond of infinite size and no depth to achieve this. The reason the sideponds at Knowle are so large is to ensure that the maximum amount of water is saved, but when they empty completely into the chamber they do not fill it to half way. You have to allow for the depth of the pond in order to provide a head for the water to move down into the chamber. If you don't believe me, go and look at the levels of the sideponds at Knowle relative to the lock.

[Derek R.]

Take a look through Google Maps at the aerial shots of Knowle and Maffers. The area covered by each of the two side ponds at any Knowle lock is in excess of the surface area of the lock - almost by a factor of two.

Dependent on their elevation in comparison to the maximum water level in the lock (and of course on depth, and most are heavily silted now) each pond would be easily capable of taking at least one quarter of a lockful. Two obviously makes a half - 50%.

 

The side ponds at Maffers are equally large in area. Although it's a crude and inaccurate way of gauging their capacity by simply looking at aerial photography, it does give some measure of size in relationship to area alone.

 

The claim they might only retain one third or less collectively, must surely be down to displacement by silt, weed and general rubbish - plus, any leakage occuring.

[tarboat]

Take a look through Google Maps at the aerial shots of Knowle and Maffers. The area covered by each of the two side ponds at any Knowle lock is in excess of the surface area of the lock - almost by a factor of two.

Dependent on their elevation in comparison to the maximum water level in the lock (and of course on depth, and most are heavily silted now) each pond would be easily capable of taking at least one quarter of a lockful. Two obviously makes a half - 50%.

 

The side ponds at Maffers are equally large in area. Although it's a crude and inaccurate way of gauging their capacity by simply looking at aerial photography, it does give some measure of size in relationship to area alone.

 

The claim they might only retain one third or less collectively, must surely be down to displacement by silt, weed and general rubbish - plus, any leakage occuring.

At last I see why Laurence is getting so worked up about this. At no point did I state that the sideponds at Knowle retained one third or less collectively. My original post was in response to another poster stating that sideponds saved 50% and I argued that this was not possible using a single sidepond. In a subsequent post, and also in a post by Magpie Patrick we both stated that to achieve greater efficiencies required the use of multiple sideponds. If there are two sideponds at different levels serving the same lock then it could well be possible to achieve 50% water saving. This does not negate my statement that many people believe that a single sidepond can save 50% of the water and that this is a fallacy.

[Pluto]

 

You usually get a great opportunity while trying to recover from the tricky cross winds there

 

Knowle locks are actually a very neat bit of engineering. Not surprising really as they must be last seriously engineered lock flight designed

 

Richard

Only in the UK, lots have been designed and built outside Britain.

The economising lock at Minden is an interesting example of multiple side ponds, in this case built into the chamber walls. Although there are four side ponds on each side, they estimate that only 2/3rds of the water is saved.

 

[Philip]

Sorry to drag up this old topic, but to go to the original question it appears the Llangollen Canal was one such waterway to have had its gate paddles removed. Picture in the link is from the 50s.

 

http://collections.canalrivertrust.org.uk/bw192.3.2.5.2.55

 

 

There are also pictures of other locks on the Llangollen to be found in the archives showing centre paddles. The ground paddles were of the type still found to this day at Beeston Stone Lock and there is still one remaining 'swan-neck' ground paddle on the second lock down at Hurleston, although a pawl has replaced the peg on a chain.

 

Again looking through the collections you'll find 3 of the 4 locks on the Middlewich Branch had gate paddles fitted, there's a picture of Minshull Lock from the early 70s and it still had one then. No evidence of Wardle Lock having had a gate paddle, presumably because the T&M company looked after the Wardle Canal, though strangely it is now painted in Shropshire Union grey.

 

It looks like the Shropshire Union company had a system of 3 upper paddles (two ground, one gate) on all of its narrow locks. I wonder why the gate paddles were removed on all but some of the locks on the former Birmingham and Liverpool Junction section?

Edited April 14, 2015 by Philip

[Ray T]

As we have wandered a little, does anyone have a photo or a drawing of the culverts on the Grand Union locks at Hatton?

 

Richard

 

As this topic has been resurrected,

 

Courtesy of Mykaskin:

 

 

Not Hatton, but similar style.

Edited April 14, 2015 by Ray T

[Derek R.]

This is not a practice to be recommended on a GU staircase. Inexperienced hands may allow water to flood over the bottom gates onto craft below (and maybe lockside), and closing the intermediate gates will result in fiercely slamming them with the water flow unless the top paddles are dropped at the appropriate time and water movement stabilised.

 

Close intermediate gates and fill the lower chamber with water from the full top chamber. No drama, no accidents.

 

Mike's 'Snow Cold' video is excellent.

[fittie]

It is not unusual for there not to be enough water in the top lock to fill the lower lock - this might be due to low level in the pound below or a leak.

You may only find out when you try to cross the cill but not in the case of the video. If the water is running over the lower gates there would be no need to run more water down as the lock would be full and you would be able to cross the cill.

[Pluto]

The problem on British canals is the amount of rubbish in them. Using this technique is fine if it is the regular method, as on the Canal du Midi. However, on British locks, which as we know are rarely cleared of rubbish, water flows associated with the method will deposit rubbish on the sill and create excessive wear of the seal and the possibility of a large item becoming lodged.

[Neil TNC]

This method of filling a double lock is also the official way on the Grand Canal in Ireland. This is Belmont, with Alan the roving locky in control.

 

 

As you can see the top gate racks (paddles) are rather fierce on Grand Canal locks (no NPBC baffles here!) and the centre gates on many of the double locks do not have ground racks (paddles), so without a rather waterproof front end it would be rather slow work filling the second chamber the conventional way. As for missing gate paddles, in Ireland there are only a handful of locks that do not have the standard array of 4 unbaffled gate paddles. For a laid back county, the Irish canals must have some of the fastest filling locks we have ever experienced.