Canals will have to close - there's not enough replacement gates

[Marc Hartley]

Thursday 6th June - Day 6 of the Explorer Cruise

I visited the R&CT Bradley Workshop, Thursday 6th June 2019, on day 6 of the BCNS Explorer Cruise.

 

There used to be five workshops making lock gates and everything necessary to maintain the canals, but now there are only two. It is a stark warning for boaters that in the days of British Waterways the five workshops made over 400 ‘leaves’, i.e. individual gates a year. Now according to C&RT each year the two workshops normally build 180 lock gates between them, although one of the Bradley workmen told me that it was in fact only 110 or so in 2018. The number necessary for replacement each year is apparently over 200. So you can see that as they wear out and there aren’t enough replacements being made, that canals will have to close.

 

When our canals and rivers were built there was no standard template for lock gates. They were constructed using a variety of techniques and designed to navigate the local landscapes. So no two locks on our canals and rivers are alike - each one has to be sized up and built to the exact specifications for each lock, and ‘heritage’ demands that no changes be made to existing styles. 

 

An average lock gate lasts for about 25 years, and each one is built from European green oak from a single supplier, by a single carpenter, taking from two to five weeks depending on the size. So when you see a pair of gates, it was built by one man - no production line here. Steel brackets are fitted to strengthen the joints of the gate to make sure it lasts. Many of the cast iron fittings, for example the working paddle gear, are recycled and then reused on the new gates. Other bespoke metalwork such as hoops, collars and paddles are also made at Bradley. The gates are built all year round, but usually fitted in the winter stoppages, so the green oak is kept wet outside to avoid shrinkage, until they are fitted.

[Allan(nb Albert)]

Here are some old figures that show the scale of the problem -

https://www.whatdotheyknow.com/request/lock_gate_replacement_programme#incoming-1019040

 

Edited February 11, 2022 by Allan(nb Albert)

[David Schweizer]

When the lock gates at Bradford on Avon were replaced a few years ago, they came from Holland. So maybe C&RT will resource the shortfall from outside contractors.

 

 

Edited February 11, 2022 by David Schweizer

[Tracy D'arth]

I  would like to see more of the steel gates that were used in the mid '70s.  Many of these gates are still very usable after nearly 50 years.

Forget the heritage argument, just keep the canals functioning.

[IanD]

27 minutes ago, Tracy D'arth said:

I  would like to see more of the steel gates that were used in the mid '70s.  Many of these gates are still very usable after nearly 50 years.

Forget the heritage argument, just keep the canals functioning.

They're durable but are sometimes badly balanced (because steel doesn't float) and can be very heavy to open and close. There's no perfect solution to the gate problem... 😞

[Captain Pegg]

I think the premise that canals will have to close because CRT's lock gate manufacturing capability has been concentrated at two locations rather than the previous five is false.

 

By my calculation there are 4850 leaves on the network which at 180 leaves per year results in a theoretical capacity to replace every leaf at an average of 27 years. From the business perspective of supporting a number of fixed plants then two is the right number. Even if 25 years is correct (and for a number of reasons it's probably conservative) there wouldn't need to be much change to cope with the difference. For starters what specifically limits those plants to 180 gates per year. Is it staff, equipment, or perhaps storage? Is the fact that replacements are done mostly in winter a constraining factor?

 

Taking narrow locks - the gates for which are fabricated at Bradley with broad locks being done at Stanley Ferry - there are 2175 leaves on the network so even assuming they are all timber gates and the average (not minimum) lifespan is 25 years that's 87 leaves per year i.e. almost exactly one factory's worth of output.

 

The situation with broad gates is more complex because they have more variety, including as they do the standard 14' locks of the GU to the large commercial waterway locks of Yorkshire (albeit there aren't that many such locks as a proportion). Steel is much more commonly used in broad locks than narrow hence the average lifespan is almost certainly higher with broad locks. There are possibly also a number that would require specialist fabrication.

 

When you get to the detail it's a lot more complex than just the simple maths, but at base level there isn't a big problem with the capacity. It seems evident that a capacity to produce 400 was too big, and if that was the number being replaced why was that, because it seems way too high? 20% of the lock gates on the network have been added since 1990 (K&A, Rochdale and Huddersfield narrow).  If there's a problem it's with the gap between actual and potential rates of replacement.

 

Edited February 11, 2022 by Captain Pegg

[BEngo]

The larger number of leaves being replaced under BW was partly because they had a lot in service made from  cheap timber which did not last as long as planned.  They were also replacing steel with timber in some instances. 

Just before Bulbourne closed Jeff Whyatt was going round explaining that they had a future imbalance between production and demand and BW  would have to bring some gate renewals forward and defer any that could be so as to get SF and Bradley production  in sync with requirement.  I suspect the Robin Evans "do nowt" maintenance regime soon put a stop to bringing renewal forward and that CRT have enhanced that.

 

Steel gates last well, especially if blasted and epoxied at manufacture, can have the timber bits refurbished or renewed and can usually be weld repaired if rust gets to be a problem.  They are not as resilient as wood, so do not like being hit by boats and a badly distorted one can be beyond repair.  I am not sure how they compare cost wise.

 

N

[Captain Pegg]

4 minutes ago, BEngo said:

The larger number of leaves being replaced under BW was partly because they had a lot in service made from  cheap timber which did not last as long as planned.  They were also replacing steel with timber in some instances. 

Just before Bulbourne closed Jeff Whyatt was going round explaining that they had a future imbalance between production and demand and BW  would have to bring some gate renewals forward and defer any that could be so as to get SF and Bradley production  in sync with requirement.  I suspect the Robin Evans "do nowt" maintenance regime soon put a stop to bringing renewal forward and that CRT have enhanced that.

 

Steel gates last well, especially if blasted and epoxied at manufacture, can have the timber bits refurbished or renewed and can usually be weld repaired if rust gets to be a problem.  They are not as resilient as wood, so do not like being hit by boats and a badly distorted one can be beyond repair.  I am not sure how they compare cost wise.

 

N

 

That makes a lot of sense. I wondered if lesser quality materials had been used. Timber can be horribly variable even when the source is generally good.
 

ETA - just noticed your boat name!

Edited February 11, 2022 by Captain Pegg

[BEngo]

The previous one was Oak!

 

Jarrah is not much use for lock gates but I believe the Thames used to use it in the big white poles and timber dolphins  at lock entrances and the like.  Makes excellent railway sleepers I am told, because it is easy to cleave into rectangular blocks.

 

N

 

[Captain Pegg]

45 minutes ago, BEngo said:

The previous one was Oak!

 

Jarrah is not much use for lock gates but I believe the Thames used to use it in the big white poles and timber dolphins  at lock entrances and the like.  Makes excellent railway sleepers I am told, because it is easy to cleave into rectangular blocks.

 

N

 

 

Jarrah was once by far and away the most common - if not the only - hardwood used for railway sleepers in Britain but not these days as I don't think there's an FSC approved supply. Ekki is now used, or FFU.

[PD1964]

The other CaRT Lock Building yard at Stanley Ferry, 

[Pluto]

In 1928, the L&LC did a survey of lock gate age from Blackburn to Liverpool, and a pdf of the results is below. 41 years seems to have been the oldest ones, though I suspect they would not be as long lived today as it is much more difficult to source suitable wood. Two world wars destroyed much of the best timber, and with fewer people skilled in finding and identifying the best wood today, wooden gates are unlikely top last as long as formerly.

L&LC lock gate age 1928.pdf

[David Mack]

The Rochdale Canal has some gates built locally as the restoration proceded through the 80s and 90s, and some installed by BW in the final push around 2000 to get the canal fully open.  The latter were all built of oak, and most are now looking rather craggy. Some of the former were built of a close grained redish-brown hardwood, and they still look like they were built yesterday. No idea what timber was used, but it must have been more cost-effective than oak.

4 minutes ago, Pluto said:

In 1928, the L&LC did a survey of lock gate age from Blackburn to Liverpool, and a pdf of the results is below. 41 years seems to have been the oldest ones, though I suspect they would not be as long lived today as it is much more difficult to source suitable wood. Two world wars destroyed much of the best timber, and with fewer people skilled in finding and identifying the best wood today, wooden gates are unlikely top last as long as formerly.

L&LC lock gate age 1928.pdf 124.72 kB · 0 downloads

Back in the mid 70s there were gates on the BCN with carved dates back to before WW1. They must have been 60 years or more old.

Mind you they were probably impregnated with all sorts of industrial residues which won't be found so much in today's much cleaner water.

[PD1964]

I heard they once trialled a sustainable African hard wood instead of oak, but it proved too hard to machine and work with their tooling set up, so was not used. Someone may know the full story.

Edited February 11, 2022 by PD1964

[Captain Pegg]

4 hours ago, Tracy D'arth said:

I  would like to see more of the steel gates that were used in the mid '70s.  Many of these gates are still very usable after nearly 50 years.

Forget the heritage argument, just keep the canals functioning.

 

Are there many left where you are? There are very few left in the Midlands. They have poxy little balance beams and aren't nearly so nice to work as timber gates. There's a similar number of hydraulic paddles to complete the 70s feel. It wasn't a decade that deserves to be revived.

 

ETA - synthetic wood may be the way to go.

Edited February 11, 2022 by Captain Pegg

[Rob-M]

30 minutes ago, PD1964 said:

I heard they once trialled a sustainable African hard wood instead of oak, but it proved too hard to machine and work with their tooling set up, so was not used. Someone may know the full story.

Last week at Grindley Brook the chap doing the lock tour mentioned a trial of American Greenwood but said it was too hard to work with.

[Tracy D'arth]

27 minutes ago, Captain Pegg said:

 

Are there many left where you are? There are very few left in the Midlands. They have poxy little balance beams and aren't nearly so nice to work as timber gates. There's a similar number of hydraulic paddles to complete the 70s feel. It wasn't a decade that deserves to be revived.

 

ETA - synthetic wood may be the way to go.

Lots when you look closely. Boslet flight for one.  And there are still cast iron bottom gates on one lock on the South Oxford, its just as easy to work as a timber pair.

[Jim Riley]

2 hours ago, Captain Pegg said:

 

Jarrah was once by far and away the most common - if not the only - hardwood used for railway sleepers in Britain but not these days as I don't think there's an FSC approved supply. Ekki is now used, or FFU.

They have a special technique at Stanley Ferry Yard for assembling the reet gradely gates, the Ekki Thump. 

[Tim Lewis]

3 minutes ago, Tracy D'arth said:

Lots when you look closely. Boslet flight for one.  And there are still cast iron bottom gates on one lock on the South Oxford, its just as easy to work as a timber pair.

 

The OP's pictures show new timber gates designated for the Bosley Flight

 

[Tracy D'arth]

1 minute ago, Tim Lewis said:

 

The OP's pictures show new timber gates designated for the Bosley Flight

 

I did not say all the flight, but I bet the replacements are for one of the timber gates, the steel ones with concrete filled balance beams go on and on.......

[Tim Lewis]

6 hours ago, David Schweizer said:

When the lock gates at Bradford on Avon were replaced a few years ago, they came from Holland. So maybe C&RT will resource the shortfall from outside contractors.

 

 

 

Came across this from a 1960's rally brochure!

 

Edited February 11, 2022 by Tim Lewis

[David Mack]

That dates from the days of David Hutchings restoration and ownership by the National Trust. The gate pictured must have been for the wide lock between the basin and the river at Stratford.

[Captain Pegg]

36 minutes ago, Tracy D'arth said:

Lots when you look closely. Boslet flight for one.  And there are still cast iron bottom gates on one lock on the South Oxford, its just as easy to work as a timber pair.

 

The cast iron gate is at Hillmorton. Probably well over a century old. Only been through Bosley once and that was in 1998. May be next year. The one steel gate I am very familiar with is at Lapworth, agreed it isn't physically harder to move but it's small and low and you can't just lean on it comfortably like a timber gate.

 

ETA - I came back again so I've actually been through Bosley twice!

Edited February 11, 2022 by Captain Pegg

[David Mack]

41 minutes ago, Tim Lewis said:

 

Came across this from a 1960's rally brochure!

 

Wyckham Blackwell are still going, but no longer building lock gates.

https://www.wyckhamblackwell.co.uk/

[magnetman]

4 hours ago, Captain Pegg said:

 

Jarrah was once by far and away the most common - if not the only - hardwood used for railway sleepers in Britain but not these days as I don't think there's an FSC approved supply. Ekki is now used, or FFU.

BW used Ekki for some works on the K&A about 20 years ago. I had some offcuts of this stuff. It doesn't float but burns well. 

 

Not sure how good it is for lock gates. I think maybe not ideal 

 

Observer article about BW's dutch timber supplier buying arms dealer hardwoods from Liberia. 

https://www.theguardian.com/world/2002/apr/14/uk.antonybarnett

Edited February 11, 2022 by magnetman