Change of canal gauge locations

[IanM]

23 hours ago, magpie patrick said:

 

That gets messy.... 

 

Stroudwater locks were shorter and wider the T&S locks - the break of guage came at Brimscombe so the first seven T&S locks were Stroudwater size and Bournes was wide and long to allow both. Some of the T&S locks in the Golden Valley were shortened but I'm not sure the ones on the other side down to the Thames were. Overall the T&S locks were a pain as they were wide but not wide enough for two narrow boats. When built it was never imagined the narrow boat would become so ubiquitous so it was built for Thames barges

 

The Stroudwater / Thames & Severn measurement mashup was my first thought when I saw this thread but I discounted it because it didn't really stop barges and allow narrow boats as if you had a barge of the correct dimensions you could use the through route.

 

As for which locks were shortened, it's a while since I've looked into it but it seems to be that some were and some weren't.  A lot of the 90 foot locks up to the summit from Brimscombe were shortened as were the Siddington flight down the other side.  I don't think the ones in the South Cerney area were as Boxwell certainly isn't, I'm not sure about the Wildmorway ones but as you head towards the Thames they definitely are full length.

 

 

[Mike Todd]

On 21/12/2023 at 20:34, magpie patrick said:

 

It's in my original list

 

It's doubtful whether a wide boat ever went through it, but I presume the logic was to get wide boats to a particular wharf in Middlewich.

 

I haven't a clue why the barge lock in Droitwich was built wide! 

Was it not the original terminus coming up from the river  the locks in between are also wide? The separately named connecting canal to Hanbury provided an alternative link to the existing narrow W & B.

 

I assume that the original Sevrn traffic used wide barges as all the exits are wide.

[Tim Lewis]

On 22/12/2023 at 09:52, IanM said:

 

The Stroudwater / Thames & Severn measurement mashup was my first thought when I saw this thread but I discounted it because it didn't really stop barges and allow narrow boats as if you had a barge of the correct dimensions you could use the through route.

 

As for which locks were shortened, it's a while since I've looked into it but it seems to be that some were and some weren't.  A lot of the 90 foot locks up to the summit from Brimscombe were shortened as were the Siddington flight down the other side.  I don't think the ones in the South Cerney area were as Boxwell certainly isn't, I'm not sure about the Wildmorway ones but as you head towards the Thames they definitely are full length.

 

 

interestingly the Thames and Severn locks were shortened by moving in the top cill rather than moving the bottom gates which I thought would be easier!

 

photo taken on the Golden Valley flight

 

 

[IanM]

4 minutes ago, Tim Lewis said:

interestingly the Thames and Severn locks were shortened by moving in the top cill rather than moving the bottom gates which I thought would be easier!

 

photo taken on the Golden Valley flight

 

 

 

It does seem odd and more work to have done it that way.  The original cill and paddle culverts exist under the arch. 

 

One book does mention that at low water levels air could get trapped under the arch and blow the top off when compressed as the lock fills.

[magpie patrick]

On 29/12/2023 at 04:18, Mike Todd said:

Was it not the original terminus coming up from the river  the locks in between are also wide? The separately named connecting canal to Hanbury provided an alternative link to the existing narrow W & B.

 

I assume that the original Sevrn traffic used wide barges as all the exits are wide.

 No - the "Barge Lock" is on the Junction canal, the Barge Canal (originally just the Droitwich Canal) had it's terminus in what is now Vines Park and had no access to the Salwarpe although there was a feeder pipe. 

 

On 02/01/2024 at 10:09, Tim Lewis said:

interestingly the Thames and Severn locks were shortened by moving in the top cill rather than moving the bottom gates which I thought would be easier!

 

photo taken on the Golden Valley flight

 

 

 I'd often wondered what possessed them to do it that way! New recess and cills at the bottom would have been so much easier

[Pluto]

32 minutes ago, magpie patrick said:

 I'd often wondered what possessed them to do it that way! New recess and cills at the bottom would have been so much easier

It could be because it was more difficult to build the foundations. Extending the chamber walls could have required inserting piles, while excavating the upper end could have created a solid foundation or the shorter piles to build on would have been cheaper.

[IanM]

3 minutes ago, Pluto said:

It could be because it was more difficult to build the foundations. Extending the chamber walls could have required inserting piles, while excavating the upper end could have created a solid foundation or the shorter piles to build on would have been cheaper.

 

The locks were shortened, not lengthened.  Cutting new recesses and moving the lower gates would have been much easier.

[Captain Pegg]

39 minutes ago, IanM said:

 

The locks were shortened, not lengthened.  Cutting new recesses and moving the lower gates would have been much easier.

How were these locks drained, via gate paddles or ground paddles? If the latter it could explain why altering the top of lock was easier as that appears to be have been achieved without altering the original culverts.

 

Also works to the bottom end of a lock might have required a lot more de-watering activity than alterations carried out inside the top gates.

[magpie patrick]

1 hour ago, IanM said:

1 hour ago, Pluto said:

It could be because it was more difficult to build the foundations. Extending the chamber walls could have required inserting piles, while excavating the upper end could have created a solid foundation or the shorter piles to build on would have been cheaper.

The locks were shortened, not lengthened.  Cutting new recesses and moving the lower gates would have been much easier.

 

 

That was my thought too - no extension needed, although I guess the new cill and recesses might need stronger foundations than the invert, so it may have been based on experience when building the locks

 

33 minutes ago, Captain Pegg said:

How were these locks drained, via gate paddles or ground paddles? If the latter it could explain why altering the top of lock was easier as that appears to be have been achieved without altering the original culverts.

 

Also works to the bottom end of a lock might have required a lot more de-watering activity than alterations carried out inside the top gates.

  Gate paddles

 

A number of the locks modified in this way are quite close together so dewatering wouldn't have been a major problem, although as you suggest moving the top gates inward only involved dewatering the lock - as the crown of the arch is below water level it couldn't have been done with the lock in water, but it could have been done without draining the pound above. 

 

The more I think about it though, stop planks or a bund below the lock (or in it) would have been needed whichever solution was applied. 

For all the above, as @Pluto has pointed out before, it's what they thought to be true that matters, if they thought it was easier at the top...

 

Just to add - the cynic in me wonders if they did this so it wasn't easily reversible - just in case some Thames Barge operator objected after the event.

[Mike Todd]

On 05/01/2024 at 10:24, magpie patrick said:

 No - the "Barge Lock" is on the Junction canal, the Barge Canal (originally just the Droitwich Canal) had it's terminus in what is now Vines Park and had no access to the Salwarpe although there was a feeder pipe. 

 

 I'd often wondered what possessed them to do it that way! New recess and cills at the bottom would have been so much easier

I am sure I managed in the past to locate separate maps of the two canals but not right now. However, as the main purpose of the Barge Canal was to trade salt from the town down to the Severn (and beyond) would they not want to serve the salt mill just above the Barge Lock (on the other side of the main road) as well as the one alongside SaltWay/Vines Park? Otherwise, why build it wide?

[magpie patrick]

59 minutes ago, Mike Todd said:

 Otherwise, why build it wide?

 

That was exactly my question, and it appears the answer was to serve a wharf on the Salwarpe - nevertheless the Barge Lock was built as part of the Junction Canal not as part of the Barge Canal. 

[David Mack]

4 hours ago, Mike Todd said:

However, as the main purpose of the Barge Canal was to trade salt from the town down to the Severn (and beyond) would they not want to serve the salt mill just above the Barge Lock (on the other side of the main road) as well as the one alongside SaltWay/Vines Park? Otherwise, why build it wide?

The Barge Canal was built wide to accommodate the trows already in use on the Severn. The Junction Canal was built narrow since boats using it would have to fit the Worcester & Birmingham locks, but as part of that later project the Barge lock was built wide so that trows trading downstream could access the mill by the main road (and the Barge Canal locks were extended to 70 ft length at the same time).