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Widest & Deepest narrow locks. Where are they?


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The reason for my question on the width of oversize narrow locks was due to a spate of comments some years ago by Laurence Hogg who made the point that many working “Narrow Boats” were built as much as 7’-3”/4” wide. 
So if this was in fact the case where did they operate?
I have in the back of my mind that some of the S&W sponsored canals were built to 7’-4” but I may be mistaken. That said, I have seen printed dim’s of 7’-4” beam locks but again I cannot recall where.  So maybe my question should have been where did craft with a beam of between 7’-1” and 7’-6” operate on what are now “generally known” as narrow canals.

My curiosity was re kindled more recently when I came across a modern 7’-4” nb in a 7’-0” marina mooring (presumably a Welsh refuge).

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4 minutes ago, oboat said:

 

The reason for my question on the width of oversize narrow locks was due to a spate of comments some years ago by Laurence Hogg who made the point that many working “Narrow Boats” were built as much as 7’-3”/4” wide. 
So if this was in fact the case where did they operate?
I have in the back of my mind that some of the S&W sponsored canals were built to 7’-4” but I may be mistaken. That said, I have seen printed dim’s of 7’-4” beam locks but again I cannot recall where.  So maybe my question should have been where did craft with a beam of between 7’-1” and 7’-6” operate on what are now “generally known” as narrow canals.

My curiosity was re kindled more recently when I came across a modern 7’-4” nb in a 7’-0” marina mooring (presumably a Welsh refuge).

 

Those are good points well made and reinforce the view I often express that there is no such thing as a standard narrow boat, and thus also no such thing as a standard narrow lock, there are subtle but important variations in length and beam and it is unreasonable to expect, for example, that a GU Town Class narrow boat can go everywhere on "narrow canals" - the designers of such boats never dreamt anyone would try and take them up the Chesterfield Canal for example - it doesn't mean they won't fit, it means the designer never intended them for such far flung waterways

Edited by magpie patrick
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22 hours ago, alan_fincher said:

"Widest" "Narrow" Lock is something of a contradiction in terms.

How do you define a " narrow" lock, please?

 

If you mean a lock not wide enough for two 7 foot narrow boats, then there are plenty that have either achieved that by accident, such as the many on the Rochdale where the walls have moved inwards, or by design, such as those on the River Stort.

 

If however you mean a lock built as a "generous" narrow boat size, then the lock width on something like the Aylesbury arm is probably closer to 8 feet.

How you quantify the "weir" locks on the Oxford is another matter again.  The gates are one narrow boat wide, bu the lock are three narrowboats wide, providd two of the boats are not full length.

Interesting 2nd comment on the Aylesbury is that consistent all the way down?

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9 minutes ago, magpie patrick said:

 

Those are good points well made and reinforce the view I often express that there is no such thing as a standard narrow boat, and thus also no such thing as a standard narrow lock, there are subtle but important variations in length and beam and it is unreasonable to expect, for example, that a GU Town Class narrow boat can go everywhere on "narrow canals" - the designers of such boats never dreamt anyone would try and take them up the Chesterfield Canal for example - it doesn't mean they won't fit, it means the designer never intended them for such far flung waterways

Unfortunately this "Standard" concept has now been reinforced in print with lazy journals now quoting 6'-10" as the max beam of a Nb. and several "official guides" quoting 7'-0" for just about anything.

What I now find even more amusing is that CRT after touting 6'-10" as a max nb size, the new licence fee size dim cuts in at 7'-1".

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The new Lock 3E on the Huddersfield Narrow, outside Kirklees College, has been built much wider than standard - certainly over 8ft. I've no idea why.  I've tried to find a pic with a boat in it to get an idea, but can't yet.

 

Here we are.  This is Cygnet below the lock.  I think the lock is that wide - I don't remember any narrowing on going in.  If so, then this 'narrow' lock is over 9ft wide.

 

 

Lock 3E.jpg

Edited by Mac of Cygnet
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44 minutes ago, magpie patrick said:

 

Those are good points well made and reinforce the view I often express that there is no such thing as a standard narrow boat, and thus also no such thing as a standard narrow lock, there are subtle but important variations in length and beam and it is unreasonable to expect, for example, that a GU Town Class narrow boat can go everywhere on "narrow canals" - the designers of such boats never dreamt anyone would try and take them up the Chesterfield Canal for example - it doesn't mean they won't fit, it means the designer never intended them for such far flung waterways

The Royal Commission volume IV, 1908, does give some dimensions which suggests a variation in narrow lock width, with the SUC and Griff Colliery arm given as 6ft 10in, and the Chesterfield at 6ft 10.5in. Most of the other narrow canals give the usual 7ft, though some are given as slightly wider. As a generalisation, the first narrow canals had a length of lock based on the flats and barges in the NW, so 69ft, with a little bit added on for the rudder, resulting in the standard 72ft. The breadth was originally suggested as 6ft by Brindley, but a meeting of all the then narrow canal companies decided upon 7ft, as described in my book below. Measurement was not particularly well standardised then, so early narrow canals often tend to be slightly generous. By the 1790s, the mid-period narrow canals were built to a minimum, so the locks are tight, while the post 1810 narrow canals tend to the generous as a little excess in dimensions was found to be useful in operation. I haven't done any detailed examination of the figures for this, but it seems to work when looking at a few canals. Given the lack of standardised measuring implements, there will probably always be some variation. I suspect each engineer had his own standard measuring tools which had to be followed on the canals he built. Perhaps someone can get their ruler out…

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51 minutes ago, Mac of Cygnet said:

The new Lock 3E on the Huddersfield Narrow, outside Kirklees College, has been built much wider than standard - certainly over 8ft. I've no idea why. ...  a pic with a boat in it to get an idea, ...

spacer.png

 

 

A few thoughts on Lock 3e here and a picture of the earlier location of lock 3E (both from 2016)

 

 

spacer.png

 

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50 minutes ago, Richard Fairhurst said:

The widest narrow lock is probably that one in the Fourteen Locks (Cefn flight) on the Monmouthshire's Crumlin Arm with a layby at the top...

I would put that down to being a special, say a One & a half lock. CRT give the Mon& Brec as 8'-5" with a headroom restriction at Ashford Tunnel. That said, CRT are renown for not keeping STUFF up to date.
Work some time ago should now have made the 8'-5" into 9ft.
But M&B is not in England. I would be interested to know if the original 9ft has in fact been recovered?

Edited by oboat
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The original lock 20 of the BCN at Aldersley was 10ft, which may be regarded as a Simcox Lock and Stenson on the Trent and Mersey (Brindley) 12ft 4in. Amongst the many listed above some are wide locks. But is Tuel Lane the deepest, what is the depth of the Kennet & Avon Lock at Bath that takes boaters onto the Avon. The thing I recall about that lock is is the chapel roof adjacent that states "prepare to meet thy god"

 

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1 hour ago, Richard Fairhurst said:

The widest narrow lock is probably that one in the Fourteen Locks (Cefn flight) on the Monmouthshire's Crumlin Arm with a layby at the top...

 They don't really count as narrow, being designed for vessels over 8 feet wide! 

 

46 minutes ago, Heartland said:

The original lock 20 of the BCN at Aldersley was 10ft, which may be regarded as a Simcox Lock and Stenson on the Trent and Mersey (Brindley) 12ft 4in. Amongst the many listed above some are wide locks. But is Tuel Lane the deepest, what is the depth of the Kennet & Avon Lock at Bath that takes boaters onto the Avon. The thing I recall about that lock is is the chapel roof adjacent that states "prepare to meet thy god"

 

 Bath Deep Lock is just under 19 feet deep - it is user operated and thus is the deepest user operated lock on the system - it is, however, wide! Bath Deep Lock combines the fall of the former Bridge Lock (9) and Chapel Lock (8) and is more or less on the site of Bridge Lock - nothing remains of either of the old locks and one can't easily tell where Chapel Lock was other than the obvious - it was next to the Chapel you refer to.

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3 hours ago, oboat said:

Interesting 2nd comment on the Aylesbury is that consistent all the way down?

Yes.    CRT even  undertook to maintain the extra width when the towpath under Bridge 16 (?  The one between Broughton Lock and the ring road bridge) was renewed a couple of years back.  

There was also, at one time,  a plastic boat moored at Circus Field which took advantage of the extra width.  Cannot remember how wide it actually was though.

 

N

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10 hours ago, oboat said:

 

The reason for my question on the width of oversize narrow locks was due to a spate of comments some years ago by Laurence Hogg who made the point that many working “Narrow Boats” were built as much as 7’-3”/4” wide. 
So if this was in fact the case where did they operate?
I have in the back of my mind that some of the S&W sponsored canals were built to 7’-4” but I may be mistaken. That said, I have seen printed dim’s of 7’-4” beam locks but again I cannot recall where.  So maybe my question should have been where did craft with a beam of between 7’-1” and 7’-6” operate on what are now “generally known” as narrow canals.

My curiosity was re kindled more recently when I came across a modern 7’-4” nb in a 7’-0” marina mooring (presumably a Welsh refuge).


When descending a 71’6” x 7’ 0.75” wide ex-GUCCCo boat through many of the nominally 70’ x 7’ single leaf gated locks of the BCN it is necessary to use the additional width of the lock over and above that of the boat to angle the boat to enable the bottom gate to swing past the bow of the boat.

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On 14/11/2022 at 09:58, Pluto said:

The Royal Commission volume IV, 1908, does give some dimensions which suggests a variation in narrow lock width, with the SUC and Griff Colliery arm given as 6ft 10in,

Grand Union boats of more than 7ft wide regularly used the Griff Colliery arm so this is likely to be incorrect (unless some bridge hole widening was carried out between 1908 and the 1930's). There were no locks on the arm, just 3 bridges, only one of which  was known to be tight (in height) where cratches of empty boats had to be taken down. This is the Coventry Road bridge which was rebuilt to full navigational dimensions in 1970 after traffic had ceased.

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On 14/11/2022 at 10:50, Richard Fairhurst said:

The widest narrow lock is probably that one in the Fourteen Locks (Cefn flight) on the Monmouthshire's Crumlin Arm with a layby at the top...

 

Picking up on this one again - the other distinguishing feature of narrow canals isn't just the width of the boats (approx 7 feet) but their length - 70-72 feet, broad canals and rivers have varying lock lengths from around 55 foot to well over 80 foot, but narrow boats are (or were) very much "about 70 foot long. 

 

The south Wales canal boats were short - the Mon and Brec were 64 foot long, the Glamorgan and Neath were 60 foot (and boat approx 9 foot wide) - the Swansea was the closest to narrow boat standard and 69 foot by 7 foot 6 inches. 

 

Incidentally, if the Glamorgan were defined as narrow it would undoubtedly have had the deepest narrow lock - the two rise at Aberfan had a fall of 29 feet so about 14 foot 6 for eaxh chamber. Only  apart of the wall survives now. Picture of them below taken from the linked website

 

http://www.alangeorge.co.uk/glamorganshirecanal_page2.htm

GlamorganshireCanal_AberfanLocks_Cropped_small.jpg

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Doesn’t it depend on the height of the pound above and the pound below for the actual drop?  Tardibigge alway feels very deep but is often a constant drop.  I didn’t consider any of the Ashton locks so deep last year. York Street always feels deep partly as the bridge hole and towpath inaccessibility at the bottom makes it feel dark - crew members often long deserted the boat going up.
As Marple pounds are short and some gates leaky it’s quite possible to have a very full pound then a very empty one so have the greatest drop. Perhaps at times  are the deepest narrow links in the system? 

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2 hours ago, Stroudwater1 said:

Doesn’t it depend on the height of the pound above and the pound below for the actual drop?  Tardibigge alway feels very deep but is often a constant drop.  I didn’t consider any of the Ashton locks so deep last year. York Street always feels deep partly as the bridge hole and towpath inaccessibility at the bottom makes it feel dark - crew members often long deserted the boat going up.
As Marple pounds are short and some gates leaky it’s quite possible to have a very full pound then a very empty one so have the greatest drop. Perhaps at times  are the deepest narrow links in the system? 


At any given moment in time that is of course the case. However every pound has a fixed weir level to give the designed/nominal fall of the lock.

 

Tardebigge top is 11’ 0” and as you state doesn’t tend to vary much.

 

It’s hard to imagine any state of variation in levels that would make a 13’+ lock appear to be anything other than very deep indeed.

 

Edited by Captain Pegg
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1 hour ago, Captain Pegg said:

It’s hard to imagine any state of variation in levels that would make a 13’+ lock appear to be anything other than very deep indeed.

 

 Agreed, and the factor most likely to reduce the fall is the upper pound being down rather than the lower pound being up - it is not uncommon at Marple to see pounds 18 inches down and still passable - 18 inches UP would be over the towpath. If the upper pound is down the apparent fall when looking at the lock won't be altered. 

It is for this reason that, to my eyes, Etruria top looks deeper than anything esle, it has rather more spare wall when full. 

 

As an aside, having grown up with Marple locks, it still takes me slightly by surprise elsewhere when I can step off the lockside onto the cabin roof with the lock empty!

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On 16/11/2022 at 08:59, magpie patrick said:

 Agreed, and the factor most likely to reduce the fall is the upper pound being down rather than the lower pound being up - it is not uncommon at Marple to see pounds 18 inches down and still passable - 18 inches UP would be over the towpath. If the upper pound is down the apparent fall when looking at the lock won't be altered. 

It is for this reason that, to my eyes, Etruria top looks deeper than anything esle, it has rather more spare wall when full. 

 

As an aside, having grown up with Marple locks, it still takes me slightly by surprise elsewhere when I can step off the lockside onto the cabin roof with the lock empty!


I think the Worcester & Birmingham mastered the narrow lock with their easy to operate and quick to fill and empty 7’ locks that are also very stable.

 

Deep locks are hard work.

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