Staircase locks - differing chamber depths

[Tim Lewis]

3 hours ago, Dav and Pen said:

In France and also in Ireland the double locks and also the odd triple are worked with middle gates open and water cascaded from the top gates until the level is reached. At a double on the grand canal in Ireland we nearly lost our NB as the water arched  over the cill straight into the front well, luckily the doors were shut. It took a lot of shouting to get the lockies attention.

The earliest staircase locks I know of were built built in France in the 1600’s at a place now named after them Rogny les Sept Ecluses. They are now bypassed by 5 locks.

 

 

 

 

Castelnaudeay (sp)

 

 

[Derek R.]

That looks positively dangerous.

[TheBiscuits]

On 04/02/2021 at 11:59, magpie patrick said:

Odd structures arose in many places although as a general rule the Brits and Irish seem to have been more level headed than those on the continent - I don't think we had any round locks or ones with four or even five entrances for example - there was one with two separate upper entrances on the Arbury Canals but that's it. 

 

 

There are some odd ones.

 

Diamond

Wyre Lock on the River Avon  :  https://canalplan.org.uk/place/dsem 

 

 

Cruciform

Upper Lode Lock, River Severn  :  https://canalplan.org.uk/place/0ood

 

 

 

Dunno what you'd call it - Lozenge?

Aynho Weir Lock, Oxford Canal  :  https://canalplan.org.uk/place/9mcg

 

 

 

Not even going to try and describe the shape ... (The full lock, not the little bit)

Leeds Lock, Aire & Calder Navigation  :  https://canalplan.org.uk/place/v682

 

 

[David Mack]

There's also the strange Lock 11 in the Fourteen Locks flight on the Crumlin Arm of the Monmouthshire Canal which has 'shelves' at different heights on either side.

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[magpie patrick]

Okay okay, I hear you, we have some odd  ones! 

The Sea Lock at Cefn (the local name for that lock with shelves) is in an "almost" staircase of three, the locks are bratch style - and I once did sums as to how much extra water it used and how much shallower it would have to be. It adds something like 50% to the volume, and to compensate the locks (About 11 feet each) would end with a thirteen footer top and bottom and a seven foot one in the middle. It was probably a passing place as it's a three in the middle of several twos. 

 

The others all have logical explanations except lower lode. I know it was lengthened but I don't know why they didn't do a proper job. 

 

Leeds lock has been two locks side by side, and when extended it became a very odd structure indeed. 

[ditchcrawler]

2 hours ago, David Mack said:

There's also the strange Lock 11 in the Fourteen Locks flight on the Crumlin Arm of the Monmouthshire Canal which has 'shelves' at different heights on either side.

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Isn't that like the one in the Ellsmere museum 

[magpie patrick]

10 minutes ago, ditchcrawler said:

Isn't that like the one in the Ellsmere museum 

No, those bays are actually in the lock - they are different depths. When the lock is full a boat can be moved over onto them. 

 

The lock is in the middle of a bratch style three-rise, amidst a sequence of bratch style two-rises. I've heard various theories as to why this lock was built like this, the most plausible is it was a passing place, an ascending boat could move sideways in the full lock, the descending boat could then move into the lock, move sideways out of the way so the ascending boat could go central again and proceed into the top lock. I measured the bays some years ago, they are big enough and the right shape, the non-towpath bay is quite shallow, it would have had about two feet of water over it, the towpath side about four foot six inches, suggesting they expected loaded boats in one direction only. Whether it was ever used as a passing place is another matter. 

 

Alternative suggestions I've heard are that there was a wharf here and this meant a boat could be loaded and unloaded without blocking the canal (serving what? And why two bays) or that its a dry dock - the trouble is it floods every time you fill the lock and again, why two bays. 

[TheBiscuits]

14 minutes ago, magpie patrick said:

or that its a dry dock

 

Drat! forgot that one ...  Anyone know which it is?

 

 

(Obviously I know because I took the picture!)

[magpie patrick]

35 minutes ago, TheBiscuits said:

 

Drat! forgot that one ...  Anyone know which it is?

 

 

(Obviously I know because I took the picture!)

Hatherton Branch - second lock up - is it still in use? 

 

There were a few lock/dry dock combinations related to the Canal du Midi - two rises in which the lower chamber could be overfilled to get a boat onto the ledge. 

 

Rather more drastic is the dry dock at Portna on the Bann in Ireland which involves draining the canal and blocking the navigation! It is related to a staircase lock as Portna is a double lock 

Edited February 5, 2021 by magpie patrick

[Derek R.]

That arrangement at Leeds Lock, though probably not intended, would be useful if a tug was towing lighters. Room for several vessels if using the bottom-most gate and the top-most.

[TheBiscuits]

16 hours ago, magpie patrick said:

Hatherton Branch - second lock up - is it still in use? 

 

It certainly was when I took that photo in 2019.

[Pluto]

2 hours ago, Derek R. said:

That arrangement at Leeds Lock, though probably not intended, would be useful if a tug was towing lighters. Room for several vessels if using the bottom-most gate and the top-most.

This is the plan for enlarging Leeds Lock circa 1870. At the time, locks were being enlarged elsewhere on the navigation to allow compartment boats to operate efficiently. There were plans for compartments to carry general cargo, and some were fitted with hatches to protect the cargo. It was expected that these would work up to Leeds, hence the enlargement of the lock .There are some compartments in the background of the view of Clarence Dock. 

[magpie patrick]

19 hours ago, Pluto said:

This is the plan for enlarging Leeds Lock circa 1870. At the time, locks were being enlarged elsewhere on the navigation to allow compartment boats to operate efficiently. There were plans for compartments to carry general cargo, and some were fitted with hatches to protect the cargo. It was expected that these would work up to Leeds, hence the enlargement of the lock .There are some compartments in the background of the view of Clarence Dock. 

 

 

I admire your archiving Mike - species have evolved and gone extinct in the time it takes me to find things!

 

Do my eyes deceive me or is the upper (northern) lock of the pair slightly smaller? The proposed extension to the lock was built like that as can be seen from other photos - it must take a while to fill if the extension gates are used. 

 

[Pluto]

The upper lock is indeed smaller, and is, I think, the last remaining lock from the 1777 enlargement of the A&CN. These improvements were the result of the promotion of the Leeds & Selby Canal by supporters of the L&LC in Leeds. The A&CN locks were smaller than those on the L&LC, not surprising as they were built 70 years previously, so the improved A&CN seems to have been built to L&LC standards, with Leeds Lock being the same size as those on the L&LC. The lock alongside was built during the improvements of the 1820s, and is slightly wider and longer, with the subsequent extension by means of a new lower gate being added circa 1870.

[Heartland]

Well when Tom Rolt encountered Blandshardstowns locks, could this be the Irish Way ?

 

 

[Dav and Pen]

53 minutes ago, Heartland said:

Well when Tom Rolt encountered Blandshardstowns locks, could this be the Irish Way ?

 

 

Defiantly they still do the same. Bit dodgy with a narrowboat especially if the keeper wanders off.

Edited February 17, 2021 by Dav and Pen
Spell

[matty40s]

4 minutes ago, Dav and Pen said:

Defiantly they still do the same. Bit dodgy with a narrowboat especially if the keeper wanders off.

I think I've seen MikeAskin do this at Bascote too!!

[Ronaldo47]

On 03/02/2021 at 16:09, Tacet said:

A fast way to ascend a Bingley-style staircase (when no-one important is watching) and all chambers are at the low level (i.e. the previous boat has descended) is to draw all the intermediate and the top paddles at then drop each set (working uphill) when the relevant chamber has made the correct level.

In the Queen's jubilee week of  1977, the Foxton staircase did not have a lock keeper, and arriving at the bottom lock we found a boat unable to complete its descent due to low water level in the passing pound. I therefore adopted a similar method,  opening all the paddles in the top five locks in order to raise the level in the passing pound to allow the descendng boat to cross the entrance cill, and then went back up shutting them all.

Edited February 19, 2021 by Ronaldo47
Typos