Brindley Gates

This representation of rising stop gates or ‘Brindley Gates’ shows how they might have looked when installed on the bed of the canal. Either gate could pivot towards the upright in the centre, depending on which way the water was flowing. Edward Paget-Tomlinson

We are all familiar with the use of stop planks to close off a section of canal in an emergency. However, as has been demonstrated in several recent incidents, by the time a breach is reported and staff have reached the scene, most of the water is lost, with potentially devastating effects both to boats on the canal and to property nearby. This problem was recognised from the earliest days of artificial navigations and an ingenious solution was found, usually attributed to no lesser person than James Brindley. Few boaters today are aware of the solution, as it mostly lies hidden beneath the water.

The concept is similar to that of lock gates, but pivoting on a horizontal, rather than vertical, axis. The gates, often in pairs, lie flat across the bottom of the canal at a suitably narrow place, usually a bridgehole. The theory is that, if a breach occurs, the flow of water causes one of the gates to rise to a vertical position, where it is held by a sturdy post or stonework, and stops the water flow.

I first came across these in research into the Cromford Canal. I was puzzled by the apparently unnecessary length of the ‘narrows’ at many bridgeholes between Cromford and Ambergate.

Perhaps the most detailed and understandable diagram of how the Safety Gate worked was published in Rees Cyclopedia of 1819. It is explained that AB is the top of the canal wall; CD is the surface of the water; QS the bottom of the canal; EFGH is a pier of hewn stones or oak timber; IEG and HFK are recesses let into the wall; LM and NO are the rising gates turning on centres or hollow-quoins at M and N. Rees then states mysteriously that “Each gate is balanced by a counterweight, so that they rest in the position shown”. He also explains that the slight drop in the canal bed at PI and RK allowed water to flow under the gate to help it to rise in case of a breach. Stop Gates, lifted by a chain, did not need this feature.

An early and rather simplified representation of ‘Brindley Gates’ as portrayed in Arthur Young’s eye-witness account A Six Months Tour Through the North of England.

Kennet & Avon Canal

In 2000, when the Limpley Stoke section of the K&A was drained prior to concrete relining, a curious underwater structure was discovered at a narrows just east of Dundas.

As the work was supported by the Heritage Lottery Fund, English Heritage took a special interest, despite the structure not being listed nor in a Conservation Area. EH asked British Waterways to build their haul road around, rather than over, the site.

As well as the almost intact gate, there was a paddle with a wooden shaft with holes in to assist in raising it to refill the canal. One small but significant detail noted was a slot in each wall at the base (facing opposite directions) adjacent to where the (wooden) spindle fitted. This would have allowed the gate to be put in place askew and twisted into its sockets; the slots were presumably then filled with wooden wedges to keep the gate in place. The spindle found was the same as those on the heel of early lock gates.

It was thought that the central upright post, against which the raised gates would seal, had an extension upwards with a pulley to assist in winching gates up manually for routine canal maintenance.

EH agreed to the timber work being removed for preservation off site and requested BW to cover all hard engineered surfaces with compacted stone and a membrane before pouring concrete. In this way it could be excavated in future and new wooden gates could be placed there.

The gate and other features are now on display at the Kennet & Avon Canal Trust’s museum at Couch Lane, Devizes (01380 729489; www.katrust.org).

Probably the most intact ‘Brindley Gate’ discovered to date was on the Kennet & Avon Canal. The construction detail can clearly be seen here. This gate incorporated a paddle to assist with refilling the drained pound. The wooden upright in the recess in the stone wall was what the gates sealed against when in the vertical position, and had a short extension incorporating a pulley to assist in manaully raising the gate. 

Robert Coles

Robert Coles

Robert Coles

This drawing of the gate found on the Kennet & Avon Canal also shows a concave floor with stone support block beneath the gate. It is thought that, if kept free of silt, this would assist in the raising of the gate in the case of a breach.

Cromford Canal

When contractors were working on relining a section of the Cromford Canal at Leashaw Bridge, north of Whatstandwell, they came across some ‘mysterious’ remains as they were dredging beneath the bridge. They had no idea that these might be of historic interest. Derbyshire County Council canal ranger Bob Jeffries was belatedly alerted to this and visited the site, after it had been refilled, to rescue remaining artefacts from the ‘dredgings’. He also made a drawing of what the contractor recalled about the site when excavated.

There is evidence of at least five similar installations on this canal in the 5 miles between Cromford and Ambergate (at bridges 1,2 9,13 and 14). They were installed to protect it as it clings precariously to the hillside on its 141/2-mile summit pound through hilly terrain. Particularly as the canal is part of the Derwent Valley Mills World Heritage Site, it is to be hoped that a proper archaeological excavation of an undisturbed site can be financed in the future.

Basingstoke Canal

Bob Otter recalled seeing the crescent shape cut into the stonework of a bridge on the Basingstoke Canal, at the east end of the long Ash Embankment. If this was so, he thought it would be likely that there was a second at the western end, unless the proximity of Ash Lock was relied upon at this side. Roger Cansdale confirms that such a feature still exists at Mytchett Place Bridge. Judging by the way the arch faces, it was intended as a safety device in the event of a breach in the embankment on the west side of Mytchett Lake. Although the bridge was rebuilt in 1994, the arch feature was retained.

The half-crescent in the offside of Mytchett Place Bridge suggests that a single gate was installed at this point. There is also a recess on the towpath side. This bridge was rebuilt by volunteers in 1994, incorporating the base of the original bridge. 

Roger Cansdale

Roger Cansdale

The drawing made from the contractor’s recollection of the excavated site at Leashaw. Bob Jeffries

The distinctive curved recess of a set of rising gates at Whatstandwell, but what purpose did the lowered stones in the centre serve, or were they a later addition? On the Cromford Canal the gates were sited in extensions of the bridge narrows rather than under the bridge itself as on many other canals.

One of two surviving angle brackets that held the side and top beams of the lifting gate together, along with the fixing nails.

I also noticed curious circular recesses in the stonework at water level in some of these extended narrows.

Then, in 2000, some almost intact rising stop gates were discovered on the Kennet & Avon Canal at Limpley Stoke, as reported in the February 2001 issue of NB’s sister magazine Waterways World. Subsequent correspondence revealed that similar gates had been used on the Droitwich Barge Canal too.

The surviving features correspond to what Rees Cyclopaedia of 1819 called ‘Safety Gates’ or ‘Stop Gates’. According to Rees, Safety Gates were designed to operate automatically, whilst Stop Gates had a chain attached by which they could be raised manually. Rees claimed that Safety Gates were counterbalanced, but it is hard to see how that could be achieved.

It would certainly have been much easier to raise chain-operated Stop Gates than to put in conventional stop planks, and it could probably have been done by a single person. However, common sense today questions how efficient the automatically operating Safety Gates might have been. If counterbalanced, they might well have been pulled up when a fast moving vessel, say a fly or packet boat, passed over them, and thus hit and damaged the boat’s bottom. What seems certain is that they would soon silt up and fail to operate at all without considerable external effort. Also, they would have been impossible to inspect or maintain without first draining the canal.

Origins

These structures have been dubbed ‘Brindley Gates’; certainly Samuel Smiles attributes their design to James Brindley in his James Brindley and the Early Engineers, published in 1874. As well as on the Bridgewater Canal, they are installed on the Droitwich Barge Canal where Brindley was ‘Inspector of Works’. The discovery of similar gates on the Kennet & Avon Canal (built 1794–1810) at Limpley Stoke, and more recently on the Brecon & Abergavenny Canal (built 1796–1812) at Gilwern, confirms that they were still being installed several decades later. The Cromford Canal was built between 1789 and 1794. One has to presume, therefore, that despite their apparent impracticability, they were considered viable for decades after Brindley first used them, and by several different engineers. In contrast, however, Matthew Boulton in a letter of 12th February 1771 to Samuel Garbett wrote: “How easy it is to pin down a Stop Gate, or how probable it is that bungling contrivance should not rise if the Canal should break down is very obvious.”

Paul Sillitoe has investigated written references to these gates and confirmed their provenance to Brindley via the Bridgewater Canal.

Andrew Kippis wrote in his Biographia Britannica (1780): “Mr Brindley displayed singular skill and ingenuity; and, in order to facilitate his purpose, he produced many valuable machines, which ought never to be forgotten in this kingdom. His economy and forecast are peculiarly discernable in the stops, or floodgates, fixed in the canal, where it is above the level of the land. These stops are so constructed, that, should any of the banks give way, and thereby occasion a current, the adjoining gates will rise by that motion only, and prevent any other part of the water from escaping than what is near the breach between the two gates.”

And a footnote dating probably from 1766 suggests that these structures were part of the original canal’s build:

“At convenient distances there are ... at the bottom of the canal, machines constructed on very simple principles, and placed at proper distances, to stop and preserve the water in case any part of the bank should happen to break down.”

A translation of an account by the German engineer Johann Ludwig Hogrewe, published in 1780, refers to a gate that “lies somewhat raised in front, on the bottom of the canal and, by means of iron pegs, pivots at the ends and can be moved from the horizontal position to the vertical in the quadrants sunk in the wall on either side.

“These are placed at both ends of the aqueducts over rivers and brooks, and also where the canal passes over raised ground between built up embankments; so that in case such a section should suffer damage and break, on both sides the pressure of water on this gap should turn the gates on their hinges, set them in a vertical position and thus assure that not the whole canal but only the part between the floodgates could run dry.”

There is an even earlier description in Arthur Young’s eye-witness account A Six Months Tour Through the North of England published in 1770 (downloadable from Google Books and also recently reprinted). Young came across one at the entrance to the Castlefield tunnel in Manchester where the coal from Worsley was unloaded. This was to enable the tunnel to be drained for repairs. As he proceeded along the canal, he wrote: “just before we came to Throstle-nest Bridge, I observed a projecting piece of masonry in the canal, which, on enquiry, I found to be the case of a canal door, for I know not what other name to give it.”

He then describes the single door sitting on the bed of the canal which would rise in case of a breach, being forced up by the decrease in pressure as the water rushes past. It remained vertical against “projecting irons made for that purpose”. The doors were set at intervals along the canal. The next one was at Leicester Bridge, then one at “Weather-Meetings” [Waters Meeting].

There is a description with diagram in The Circle of the Mechanical Arts by Thomas Martin, published in 1813, also available on Google Books. However, Martin’s description differs from Rees and others, in that his ‘Safety Gates’ appear to be conventional vertically pivoting gates, such as are to still be seen on some canals. He goes on to say that there is also “a contrivance of a similar nature called Stop-Gates, the construction of which does not differ materially from the Safety Gate, except in its being made to lie flat at the bottom of the canal, instead of being balanced above. The mode of raising the gate is by a chain, which is fixed to the gate under water.”

Christine Richardson, author of James Brindley, Canal Pioneer (Waterways World Ltd, 2004), thinks that Brindley might have installed the rising gates to appease landowners who were concerned with the potential of the new canal to flood their land.

Future Investigation

Hopefully finance will be forthcoming in the future to further investigate one or more of these remarkable historic structures. It would be interesting to be able to compare variations in construction techniques on different canals. It seems likely that most will have been well preserved by immersion in water, and those on the Droitwich Barge Canal at Salwarpe could well be in the best condition on account of the high salinity of the water.

Red House Bridge, Adlington, on the Leeds & Liverpool Canal, showing very clearly the circular recess where the rising gate would turn. There would have been a vertical post in the centre, against which the rising gate would seal. This section of canal was built in the 1790s as part of the Lancaster Canal. Mike Clark