Grantham Canal - bits of rusty metal and other interesting stuff.

This morning we started on what was hoped to be the final day for taking down the off-side wall.

Just to refresh memories, this was the view along the lock before we started.



..and this is what our colleagues had left us at the start of this morning's effort.



After few hours with the jack-hammers this was the result. Note that we have been good boys and swept up after our efforts.



..and this is now the view of the off-side taken from the same spot as the first photograph.



We didn't tackle the brickwork on the wall above the sluice aas it's in a dodgy condition and the site supervisor wants some scaffolding in place before we remove any more brick work. The next challenge is the towpath side wall. Bring it on!!

 

Only just fell over this thread as I've only recently stated posting on the forum. This is very interesting as I've been for looks at the Grantham Canal on trips into the area over the last 30 years or so and seen the progress. (I keep a copy of "Lost Canals and Waterways of Britain" in the car just in case..) The BR (GNR) link to Stewarts and Lloyds Harlaxton/Denton ironstone quarry system, the Denton Branch, ran pretty much alongside the canal near Woolsthorpe locks. The book by the late Eric Tonks "The Ironstone Quarries of the Midlands - Part 8 South Lincolnshire" (Book Law Publications, ISBN 978-1-907094-07-1) gives history/info/photos/maps of the quarry lines but only makes brief mention of the Canal, though prior to the building of the Denton Branch in 1885 the ironstone was transported from Woolsthorpe by boat, having been brought there by a narrow gauge (3') tramway from the quarry. There are a lot of potential owners of the firebar to choose from, but something like an O4, O1 or an O2 may be a reasonable guess......

Mike


(edited to add info)

 

Further to the last post, detail from the 1954 7th series OS map. Oddly, there seems to be a break in the line near Woolsthorpe Wharf which I suspect may be a mistake or just a bit omitted to accommodate the word "Locks". There seems to be a short siding there anyway. The BR/S&L interchange seems to have been near Manor Farm on the older Denton branch and just after the junction between the Denton and Harlaxton lines west of Denton Reservoir before the road crossing for the WW2 built Harlaxton line. A widened area can be seen on Google Maps. Can anyone add anything to that?



Mike

(edited to add further information)

 

The break in the line is to accommodate the word "Locks"; it is at about the point where the line crossed the canal over a wooden viaduct. When the viaduct was dismantled, some of the timbers were used to rebuild Bridge 63 (Bridle Bridge).

There was a short goods siding on the site adjacent to Locks 17 and 18, which served the local area. Our friendly farmer allows us to use this land as an access for vehicles to the off-side bank. There is still some ballast and other railway related debris lying around the site.

 

The troublesome tree that has fallen in the navigable section is still causing us work. As we have removed branches and stuff from the waterway, it became clear there was more than one tree involved. It appears that when the large, ivy-encrusted tree was blown over, it brought down another two trees (also ivy-encrusted) and that has provided us with a right tangle of trunks, branches and ivy vines to unravel.

We were making some progress using a Tirfor winch from the towpath bank when the cavalry, in the shape of our dredger 'Mudlark', arrived.



The dredger promptly set about lifting vines, trunks and other debris out of the way. All we have left to move now are two large sections of the large tree - they will be lifted out this coming weekend when we can get our work-boat, Centauri, alongside the dredger which will lift the tree's remains into Centauri's hold. The waterway will then be clear....until the next time.

Meanwhile back at Lock 15, demolition of the towpath-side wall has been taking place. The next two photos show the progress.

This was the start of Monday's effort.



And this is the view at the end of our day. The photo was taken from above where the lock gates will be. In the foreground you can just see the the scaffolding which is being erected so we can work at the higher levels of the corner posts.



Following Tuesday's efforts, the walls all but disappeared but yours truly forgot his camera to record the scene!! Note to self: 2/10 must try better.

 

Another weekend and another attempt to remove the troublesome tree. This time, we had our dredger on site right from the start and soon started making progress. It soon became clear just how large this tree was when the first big branch of the day came out of the water.



After a couple of hours of clearing debris and using the Tirfor to haul the trunk to the nearside bank, our workboat, 'Centauri', arrived on scene and was used to test if the waterway was passable. It was!! This photo shows Centauri easing past part of the tree. To give an idea of just how big the tree was, between Centauri and the strop attached to the end of a branch, that is one piece of tree.



After we had cleared more tree debris, we left the remains of the trunk alongside the bank for removal at a later date. The primary task was to clear the waterway. After Centauri had turned round and departed for the depot and we had cleared up on the towpath, all that was left was for the dredger driver to find his way back to the bank after mooring "Mudlark" in the waterway. Whilst he was coming back to his disembarking point, he didn't notice the large male swan travelling in the opposite direction. As they got closer to each other, the swan's head went down and it started to spread its wings - definitely in attack mode- whilst our man rowed on blissfully unaware. Fortunately for Ian, the swan realised he wasn't a threat and paddled serenely past him giving him a bit of "look" in doing so.

Meanwhile at Lock 15, there was a visit from WRG London who set about cleaning up the remnants of the lock walls. Amongst other work they carried out, they chopped out a lot of damaged bricks and yesterday we carried on that work; this time doing it by hand rather than machine. I'm glad I don't have to do that very day!

Here's the view at the start of yesterday showing where bricks have been chopped from lower the corner pillars.



Here's a couple of close-up photos of the upper corner posts showing them (almost) ready for new brick work.





We are now getting close to the stage when the concrete foundations for the block wall will be poured - the target for completing that phase and getting the first courses of the block bays laid(to support the front walls) is the end of April (this year!!).

Now, this is what we are all about on our society. Here is a short video taken by Mark, one of our trip boat skippers, of the trip boat and the workboat passing on a section of the navigable section. The workboat, towing the work platform, was on its way to the fallen tree, the trip boat was on a crew-training day. We hope this will become a regular site with lots more boats in the years to come.

 

Good work! Was this canal built with a puddled clay bottom and can large trees that fall in cause a leakage problem?

 

Yes, it has puddled clay as a lining. There is a stretch near Cropwell Bishop where Gypsum was extracted because it was quite near the surface. Apparently Gypsum and puddled clay do not get on well together so when we get round to restoring that part of the canal, a lining of some sort will be needed to keep the two apart.

As for potential leakage where the trees have fallen in, so far all the falls which have caused us problems, have been along the Harlaxton cutting. So, as water cannot flow uphill these particular trees did not cause any concern over leaks. Where a fallen tree might cause a problem would be where the level of the canal is above the surrounding area and the tree was immediately adjacent to the water way. C&RT keep an eye on the trees and once the bird-nesting season is over, their contractors come along and trim/fell any trees identified as in a dangerous condition or potential hazards.

 

Hello Mike,

Just catching up with your posts regarding the sidings at Woolsthorpe. Looking at an earlier OS map, it looks as though the short siding was for serving an adjacent brickworks, the siding was part of the complex of lines that also served the Woolsthorpe (Brewer's Grave) Quarries of Stanton Ironworks. On the attached map you can see the incline from the quarries coming down hill to the tippler site by the main line sidings. I have visited the area several times over the years to see the remains of the various Harston and Harlaxton Ironstone Systems, but I have never looked out for the earlier Brewer's Grave system, I can feel a visit to the area coming on very soon for a reconnoiter.



As for the firebar, it may well have come from a traction engine or steam roller, they were still in use in some places into the 1950s and 60s.

Cheers,

Alan

 

Interesting comment re gypsum and clay. After the East Coast Floods of 1953, large quantities of gypsum were spread on land that had been flooded with sea water to neutralise the salt. However, on our farm in Essex I noticed that in areas where the gypsum had been dumped after delivery (by rail, of course!) the heavy London clay soil had become a garden-like loam. In other words, the gypsum had broken-up the structure of the clay. Of course, it would have the same effect on puddled clay, but I'd never seen a reference to it before, remarkable what you find on NP.

 

The falling trees or their extraction do not damage the clay bottom then? How thick is the clay?

 

Perhaps I didn't make myself clear. The trees may have damaged the clay lining, but where we have been clearing them is in a cutting, so the likelihood of the water leaking onto the surrounding land and causing flooding is minimal to non-existant. Furthermore, the silt in the cut is quite thick due to lack of dredging so it may have cushioned the impact of the tree when it fell. Where a tree may cause problems is where the canal is above the level of the surrounding area and the tree's roots damage the integrity of the lining. The only way to check if the clay lining is damaged is to either drain the whole of the pound (all 4 miles of it) or go underwater and have a look... and I ain't volunteering to do that!!

I'm not sure of the thickness of the clay but I do know that there is a fair depth of silt in the cut. When we hauled the tree out we also dragged a lot of thick, slimy silt up with it. Unfortunately, removing silt from this part of the canal is at the bottom of C&RT's "to do" list as it is currently classed as a 'remainder water'. Getting the whole length of the canal re-opened will change that.

 

Thanks. I understood your comment about the water level but I am fairly ignorant of the details of canal construction and didn't know if the clay lining is very robust. Given the years that have passed it must be quite durable!

 

The C&RT engineers have decided that the concrete base for the block walls will be poured directly onto the clay on which the lock was built which suggests, to me at least, that it is robust enough. As this layer has been undisturbed, the engineers consider it strong enough to support everything we are going to build on it. The archaeologist isn't interested in going any further down so I guess below where we have got to, it's clay, clay and more clay. If that is mirrored further along the cut then a tree falling in isn't going to cause much of a problem. Apparently when Lock 18 was restored, the clay was only a few feet below the surface. As I mentioned in my earlier post, the presence of gypsum would cause a problem but there isn't any down this end of the canal. Next time I'm on site, I shall ask the question about the thickness of the lining and post the reply on this thread.

 

One of our society's members has posted a video of Lock 15 on You Tube. He's used his big boy's toy to show the view from above the lock.

Mark is one of our trip-boat skippers and I'm crewing with him on Easter Monday on our short, sample trips from Lock 18 for anyone who happens to be passing.

 

Heres a photo of how the brickworks site looks today. The siding was behind the second gate in the background of the photo.

 

Same here. Really enjoying this posting, keep up the good work, John. It's a shame that I'm so far away from it these days.

 

A rather pleasant but busy day on the canal on Saturday. We had three boats in operation - our trip boat on a private hire, our weedcutter on a training session and the workboat. Lock 18 was our version of the M25 during rush-hour - the trip boat is just visible coming through the lock. Did I say "pleasant"? - it was chucking it down when we started.



Just a bit of "light" pruning of overhanging branches - carefully checked before cutting in case there was any sign of new birds' nests. The earlier rain had departed by the time we were ready for a leisurely lunch in glorious sunshine; our trip boat re-appeared from under Denton Bridge and our guests very kindly donated a plate full of birthday cake, which was gratefully accepted and dispatched appropriately.



Monday was back to work at Lock 15. The scaffolders had erected a work platform at the upper end which enables us to reach the higher brickwork. Whilst we were doing that, the scaffolders were at the other end of the lock chamber putting another work platform in.



Our task for the day was to cleanup the top brickwork, so here's a couple of before and after shots.









The big news of the day was that Tuesday (today) will see the start of laying the concrete base for the block wall which will support the restored facing brickwork. We're on the way up now after all the knocking down. The excavator driver pre-positioned some stuff ready for the Tuesday gang to make a prompt start.



I asked about the clay lining , whether it was durable and its thickness. The answers were 'Yes' and "Don't know cos it varies from place to place". 'Durable" because if a fallen tree branch penetrates the lining, the clay and silt will "self-seal" around the branch. That's what the man from C&RT told me so I ain't going to argue.

 

I thought that might be the case.

 

The rebuild has begun.

This was the state of play after a couple of days of laying the first blocks on a screed surface. The initial setting-out is being done by C&RT's own bricklayer with volunteers doing the go-foring, then it will up to us volunteers to crack on with the rest of the re-build.



More screed will be laid tomorrow to finish off the initial base. The block wall, currently 1 foot high, will then be extended along the length of the chamber between the corner posts. Once that section of wall is built ,and the screed area behind it has been enclosed by shuttering, concrete, reinforced with steel mesh , will be poured to form the base proper on which bays will be built. These bays will be filled with concrete as the work progresses. There is a small change to the original design as recesses are being built into the wall to accommodate ladders - something to do with modern regulations. The first recess can be seen toward the far end of the wall. When the block wall and bays have been completed, the wall will be faced with two courses of brick.

Meanwhile, the never-ending job of brick cleaning continues. This week we started on the lower corner posts. We have to chop out damaged bricks in order to provide some sort of key for the replacements. There's still someway to go on this task.

Start work this morning.



At cease work.



Our poor pink bodies were aching by this stage, so we called it a day.