SLHS Refurbishment Of A Stratford Lock

● These items have aspects that uniquely contribute to national or world history.

Photographs

A large collection of higher resolution photos of the detail of the work undertaken by the Canals & River Trust is here:  Refurbishment_Lock53MaidenheadRoad_January2024

To return to Master page click on ‘Canal’ above.

A gate pin & cup joint (weighing 4kg and 6kg resp)

  Donated by C&RT.

Routine Refurbishment Along The Route

According to the Canals & River Trust locks will need some small amount of maintenance annually, and they will need more significant work as it comes up, but usually larger works will be expected every 10 years. Gates will get a refurbishment then but are generally expected to need replacing every 25 years. On a canal of 56 locks and 70 bridges that will mean a lot of work has to be routinely scheduled during the canal’s three-month winter rest period. And what about unusual events - there was a 500 tons landslide near Tardebigge just two weeks before work had to start on this lock.

All year round there is one canal Warden keeping an eye on the general well-being of the canal and boaters -with an additional employee during the summer months.

Days Of Decay

At the beginning of 2023 it was known that our Lock 53 was due to have it’s gates replaced at the next winter opportunity. The necessary survey of them was carried out. However whilst there the surveyor saw that the lock brickwork was suffering a lot of decay. Therefore that was factored into the the brief for the maintenance team’s work. 

Regular Servicing Wins The Day

Refurbishment Of Lock 53 at Maidenhead Road - January 2024

Locked In To Refurbishment

Next came the full lock refurbishment team. Stop planks and pumps were put in place [5,6] and a huge crane was hired which lifted out the old gates and lowered in the new ones (unfortunately this was done so quickly, and everyone was so busy, that sadly no photos were taken). The upper gate’s small old pin and cup [8] was donated to SLHS.

Maintenance To The Rescue

A preliminary team was called in. They emptied the pounds above and below the lock ie water was passed straight through this lock and the one below it [2, 3]. They made holes in the walls where necessary and inserted an injector nozzle. To this they attached a hose to a large funnel held up at ground level. Into this they poured special sealing grout to run into the earth behind the bricks to seal the ground. This is a common method used in tunneling. However with one major difference: in tunneling, for instance, when injecting into London’s gravel to stabilise around the new Jubilee Line train tunnels, they pumped vast quantities at high pressure. In this location C&RT had to be far more circumspect with the volume and pressure otherwise the entire wall could be heaved into a heap at the bottom of the lock chamber (remember the walls are a double thickness of bricks bound with ‘stretchers and headers’ as the best brickies know). The brickwork was raked out with a machine and large areas of brick re-mortared into place. Now that the culvert had been dry for some time that was also repaired.

Secondly, a wall between an alley and the towpath had slowly been undermined by a tree causing the whole length to be unstable and masonry fall. Another team came to dig this tree out [4] and then a contract bricklaying team was brought in to build new foundations and install Class A, Engineering Bricks, along the wall’s whole length.

Holey Spaces

Sure enough, after the main season ended a final survey was done in January 2024. Unfortunately, with the massive amount of extra rainfall during the winter, other significant problems were seen. The worst being that the overflow culvert was beginning to leak badly into the surrounding earth and washing the mortar out from between the lock chamber’s bricks. Quite a few had already been pushed out [1]. If this continued a catastrophic burst through might occur making far more work.

At the start of the full refurbishment works the pounds above and below the lock were drained.

Now The Real Work Could Begin..

①

②

③

④

⑦

⑧

Next the old Corp Cill Nails [9] and Corp Cill [not shown] were removed. The top of the fore bay was chipped out with a pneumatic drill [10] - notice the reinforcing wires had been kept for later (dangling lower in picture). Then the new Corp Cill installed somewhat within the brickwork but nothing like as deeply as the main cill which just can’t be seen. To protect against rolling (see Installing Corp Cills on Lock Construction page) extra-long new Corp Cill nails with barbs [11] were banged in with a sledge hammer.

To help with the nomenclature here’s a copy of the diagram from the page: Lock Construction

Upper and lower stop planks with Master/Backup pumps. The tunnel to the right is under the road above.

⑥

⑤

⑨

①⓪

Old corp cill nail.

  Donated by C&RT.

New corp cill.

New corp cill nail.

①①

Troubled Bricks Only Good For Rubble

If locks are going to last many, many winters the C&RT are now specifying Grade A Eng Bricks everywhere. Being porous and soft the old ones absorb water so frost can just gnaw away at them -especially after careless boaters’ chips have given it a head start.

They’ve Got Piles

Constantly, piles of old bricks needed to be taken away.

Lovely Jubbly

After the corners were cleaned out sturdy [13] new slots for things like the escape ladder appeared [14].

①②

①③

①④

Watery Tales

In my mind I thought lifting the gates in [15 is NOT at Stratford], setting them and their corp cills in place [16 bottom gate] and repairing the brickwork [14] meant that the job was mostly complete. However, now that we have a much hotter climate water is even more of an issue. In fact, even if dispensation allows them to take it pumping extra water to keep the canal filled costs a lot of money. Therefore preserving as much as possible is the order of the day.

Rubbery Jubbery

Thus, on the Stratford Canal C&RT are fixing neoprene strips, like draught excluders, around the edges of the gates [16]. And that’s not good enough - they have to seal. In order to check this, the workmen paint the coins and corp cill and close the gate. Hopefully all the paint is transferred to the strips. By the looks, most was [17].

Job done !

After The Gate Is Bolted..

①⑤

①⑥

①⑦

Practical Example

Now it’s time to look at one tiny but significantly clever practical idea. See next page in our practical mini-series:    4. Narrowboat Acceleration System

①⑨

Getting Cranky

Finally, this particular lock has its own feature. Because the bottom gate is so close to the road bridge there’s hardly any room for its balance beam to swing. Therefore, it is a half-size steel special [18]. I assume that it is filled with concrete.

Where boaters have to grab on to open the gate a separate frame [19] carries a handrail and the necessary paddle gearing plus ratchet.

①⑧

Photo of completed bottom gate beam to go here.

Jan 2024

New Cranked Beam waiting to be fitted and painted.