The Somersetshire Coal Canal

[davidb]

I have just had a bit of an explore round this area, Midford, not far from the Dundas Aqueduct on the K&A

 

map by courtesy of the The Somersetshire Coal Canal Societies' web site:

 

http://www.coalcanal.org/maps/m03.htm

 

I have never seen such an overgrown valley! There would be firewood forever down there, in fact all around the area if a just fraction the trees were chopped down.

 

If some trees were removed two magnificent intertwined railway viaducts would be revealed as well as the old canal structures. One of these railway lines featured in " The Titfield Thunderbolt" film from the 50s

 

Also on their website is detail of a caisson boat lift::

 

http://www.coalcanal.org/features/Caisson/Caisson.php

 

what a terrifying contraption that was, I wonder if anyone was daft enough to go through on their boat?

 

Eek David

[greywolf]

For am moment i thought they may be planning to restore it but they are just recording and enjoying it. interesting site

[Pete & Helen]

what a terrifying contraption that was, I wonder if anyone was daft enough to go through on their boat?

 

Eek David

I think this answers your question

 

"distortion was revealed when the S.C.C. Committe decided to risk a ride in the lift - which then become stuck in a submerged position. To free it, the water in the chanber was drained-off and the Committe members were eventually rescued on the point of suffocation.

 

At this point, the Committee lost all confidence in the Caisson Lock system and decided to revert to the original plan of a flight of 22 conventional locks."

[magpie patrick]

For am moment i thought they may be planning to restore it but they are just recording and enjoying it. interesting site

 

 

Errr, no, we are restoring it, but it will take a long time, we've started at Paulton and Timsbury Basins

 

http://www.coalcanal.org/sccs/Support/joining.php

 

An unsubtle hint, new members welcome!

 

Also, Heritage Open Days this weekend at Combe Hay Locks, park on the minor road NOT at Caisson House please

 

http://www.coalcanal.org/events.php

 

Magpie Patrick: Chairman SCCS

[davidb]

Thanks Patrick, I was thinking of exploring up there this weekend anyway, so a bit of guidance will be great! cheers, david

[davidb]

Thanks a lot to the volunteers of the Somersetshire Coal Canal Society who spent time yesterday showing us around their project. Quite amazing that the company managed to build a profitable canal through the difficult terrain climbing out of the Avon valley.

 

And we thouight they had things easy down South!

 

Ive got some pictures to upload later this week. Cheers, David

 

 

[Derek R.]

The caisson is but the Anderton lift, but in an enclosed tube as opposed to open tank. The advantage is clear for both - almost no loss of water, and so minimum feed supply would suffice to maintain summit levels. The closed tube would be stronger than an open tank of comparable size, but I do wonder why a 'lift', such as at Anderton, was not preferred. Ground movement must have been a constant concern, then there is all the 'mechanicals' to consider and maintain.

[magpie patrick]

The caisson is but the Anderton lift, but in an enclosed tube as opposed to open tank. The advantage is clear for both - almost no loss of water, and so minimum feed supply would suffice to maintain summit levels. The closed tube would be stronger than an open tank of comparable size, but I do wonder why a 'lift', such as at Anderton, was not preferred. Ground movement must have been a constant concern, then there is all the 'mechanicals' to consider and maintain.

 

Derek, there is a big difference, Anderton Lift hasn't got the Caisson immersed in a tank of water over fifty feet deep!

 

 

The Caisson was proposed in 1794, 80 years before Anderton opened, technology for this sort of thing was in it's infancy and even the "succesful" balance locks of the Grand Western were some years in the future. Only the tub boat inclines of the Shropshire Canals were contemporary. The K and A and the Wilts and Berks screamed blue murder when the SCC company tentatively suggested a tub boat canal instead of a narrow canal.

 

Our engineering director reckons that even in the coal canal company had our understanding of soil mechanics, with the materials and motive power available to them they'd have struggled to make this work. Leader Williams had much better Iron and hydraulics available to him, as well as superior motive power, for Anderton. In 1794, the technology to build a lift that big and the power to operate it simply didn't exist.

Edited September 15, 2013 by magpie patrick

[greywolf]

 

 

Errr, no, we are restoring it, but it will take a long time, we've started at Paulton and Timsbury Basins

 

http://www.coalcanal.org/sccs/Support/joining.php

 

An unsubtle hint, new members welcome!

 

Also, Heritage Open Days this weekend at Combe Hay Locks, park on the minor road NOT at Caisson House please

 

http://www.coalcanal.org/events.php

 

Magpie Patrick: Chairman SCCS

 

sorry i assumed after reading of some of the land owners opposition etc that it was a no goer. I hope it does well.I will give the site another read probably got the wrong end of the stick.

[magpie patrick]

 

sorry i assumed after reading of some of the land owners opposition etc that it was a no goer. I hope it does well.I will give the site another read probably got the wrong end of the stick.

 

Not to worry, the site is as up to date as we can keep it but probably needs a review rather than adhoc updates all the time. I know some bits of it have been overtaken by events

 

Many land owners (but not all) are now on our side.

[Donald Gilchrist]

 

 

Errr, no, we are restoring it, but it will take a long time, we've started at Paulton and Timsbury Basins

 

http://www.coalcanal.org/sccs/Support/joining.php

 

An unsubtle hint, new members welcome!

 

Also, Heritage Open Days this weekend at Combe Hay Locks, park on the minor road NOT at Caisson House please

 

http://www.coalcanal.org/events.php

 

Magpie Patrick: Chairman SCCS

Good luck with getting this canal back working. I remember the Timsbury bason well from my childhood in Timsbury, there was a lot more stuff still there then [mid 70's] One thing I remember was a falling down house in the field next to the end large bason, seems to have completly gone now, any idea what it was? as it seems to have been somthing to do with the canal. Will have to ask dad if he has photos of down there from that time.

[Derek R.]

I hadn't realised the lock chamber was filled with water. Quite a terrifying prospect for any person within! Hence the need to drain water for the rescue of those inspecting within, got that much now. Stuck in a leaking(?) submarine chamber could drive one insane if asphyxiation didn't get you first.

 

I had imagined counterbalancing of the caisson, not a submersible one. Must have given some challenges sealing the aperture at the lower canal end. It all sounds a little insane as a concept.

[davidb]

I believe the design came from Shropshire! !

[Derek R.]

Aah! Yes. I have a namesake who was at work locally - a Reynolds that is! Don't think he had any connections to this London born boy though!!

[davidb]

Taken on Sat 14th Sept 2013 at Combe Hay Locks open day - the flight which had to be built to replace the failed Caisson project. Its more than a century since they were abandoned, but they have survived remarkably well, there is even some wood and ironwok remaining:

 

 

 

 

 

 

 

 

Just look how the soft Bath stone has worn away with the boatman's clogs grinding away on it around the paddle gear:

 

[davidb]

These locks were really going back to nature until the Society started clearing them

 

 

 

 

 

 

 

 

 

 

 

They were well built with a neat stone invert, but why the wooden section of floor under the bottom gates?

 

 

 

 

 

 

Repaired with brickwork where the stone had been damaged by boats:

 

[Ian Mac]

Two different reasons why locks have wooden inverts either partially or in some case fully.

a) It is simpler to fit the cills to a woodern structure.

It is used where there is raising ground water, it allows the water into the canal and stops the lock being a boat and attempting to float. This does sometimes have the disadvantage that if the surrounding water table falls too far that the lock then leaks outwards, but normally the wood restricts the flow. A few locks on the Marple flight have the same construction, Also so do some locks on the Huddersfield very narrow canal. In fact Dungbooth lock 22w has a complete wooden invert unfortunately the wood has weakened over the years allowing the lock walls to rotate inwards, at the bottom, meaning that this lock is very very narrow. The construction at Dungbooth are large baulks across the width to hold the walls apart, with longitudinal planks on top to form the floor.

When it is just the cill area the planks seem to run across the chamber.

The timber used was normally Elm, which whilst kept wet is wonderful for the job, and will last almost indefinitely, however if it is then allowed to dry out it rots for fun.

[davidb]

Thanks Ian, yes, Rawlbolts would have been hard to come by in those days!

 

I guess the pressure from the closed gates would have also helped to hold the walls out,

[Ian Mac]

Thanks Ian, yes, Rawlbolts would have been hard to come by in those days!

 

I guess the pressure from the closed gates would have also helped to hold the walls out,

Wrought Iron studs and Lead work fairly well into a bell shaped hole. I think there is some other reason otherwise it would either never be done or done everywhere.