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Shropshire

Canals

  

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About Canals

 

 

Locks

 

Very early canals used Flash Locks, where there was a single gate and a boat was taken through with the water flow when opened.  Going upriver, a boat had to be pulled through.  The Pound Lock was invented in China in AD983 and this had a rectangular chamber with two Guillotine Gates, which were opened vertically.   The Mitre Gate was invented by Leonardo da Vinci in the 15th Century.  This has V-shaped gates held together by the water pressure and the first one in Britain was introduced on the River Lee at Waltham Abbey in 1574.  Both Guillotine and Mitre Gates were used on the Telford canals. 

 

All of the Shrewsbury Canal locks were built with mitred top gates and guillotine bottom gates.  The purpose behind this was that gates opening inwards took up space and the use of a lifting guillotine gate allowed four tub boats in at the same time.  The gate-lifting mechanism consisted of a wooden gantry with pulleys and chains.  A windlass was used to raise the gate and there was a counterweight to equalise the weight, originally this was simply a box of stones or scrap iron.  The guillotine gates were tricky to move as they stuck in frost and had to be prised free with bars.  They also had a habit of bouncing off the slotted sill which meant more work at the windlass.

 

Lock gates are usually referred to as a Top Gate or Bottom Gate, depending on the height of the surface of the canal on that side of the lock. So each lock has both a Top Gate and a Bottom Gate.  Lock gates have a paddle (valve) to allow water to pass through under control, thus avoiding a rush of water on opening the gate which would damage any boats in the lock.  A Gate Paddle is a small sliding door set into the gate itself and, since it is often underwater, it is operated from the top of the lock via connecting rods. An indicator post shows if the gate is open or closed.

 

A Ground Paddle has the sliding door set into the top side of the lock itself: Water flows from there through a crescent-shaped underground culvert to exit part way down the lock chamber below the lowest normal water level. Ground Paddles are normally found on Top Gates.  On the Shrewsbury Canal, a gate paddle of standard Shropshire Union design was provided on the bottom gates and the top gates had both gate paddles and ground paddles alongside. 

 

When passing upstream, the level of water in the lock chamber is first brought down to the level of the canal using the valve on the lower gate.  The lower gate is opened, the boat enters the lock and the lower gate is closed.  The valve on the upper gate is then used to raise the water level in the lock to that of the canal beyond.  The upper gate is then opened and the boat leaves the lock.  Boats moving downstream carry out the process in reverse.  Valves and guillotine gates are operated using a hand windlass and boat operators have to carry their own handle with them.  Mitre locks usually have a large arm overhanging the bank which boat operators push to open and close the gate.

 

Shropshire tub-boat locks were usually over 81ft long but only about 6ft 4in wide, made to take up to 4 tub-boats at a time.  One innovation used on some locks was an intermediate gate just over 20ft from the top gate so one boat could use the lock without wasting water.  Later locks on the Shrewsbury Canal were slightly wider at 7ft 4into take standard canal narrowboats. 

 

Tub-Boat Canals of Telford

 

When most people think of the Telford area, they associate it with the iron bridge and River Severn.  What is not generally known, however, is that Telford once had a 22 mile network of canals, traces of which can still be seen today.  The canals have left a legacy in the naming of the areas of Telford called Aqueduct and Trench Lock.  There were 5 canals as follows :

 

Canal

Miles

Locks

Opened

Closed

Donnington Wood

7

1767

1904

Ketley

1

1788

1880

Wombridge

-

1788

1921

Shropshire

10½

-

1790

1944

Shrewsbury & Newport

(Trench Branch)

9

1797

1944

 

They are called tub-boat canals because the locks were narrower, 6ft 4 inches compared to standard canals at 7ft 4 inches, as the traffic composed solely of tub-boats (see below).  The Shrewsbury & Newport Canal bypassed Telford to the north and was a standard sized canal. However, the linking branch to Trench was only used with tub-boats so was the narrower size.

 

It is widely believed that the first canal in Britain was the Bridgewater Canal near Manchester, built in 1776.  As important as this was, however, it cannot lay claim to being the first.  About AD50, the Romans built the 11 mile Fossdyke from Lincoln to the River Trent and the 40 mile Caer Dyke from Lincoln to Peterborough. These were probably more for drainage than navigation but they must lay claim to being the first man-made canals.  In 1566, the Exeter Canal was built to bypass part of the River Exe to make navigation easier. This had the first pound lock in Britain, equipped with lifting, vertical gates. The first lock with mitre gates was introduced on the River Lee at Waltham Abbey in 1574. 

 

The Bridgewater Canal was built in 1761 by the Duke of Bridgewater, to bring coal from his mines at Worsley into Manchester. One unique feature is that the canal runs underground so that the coal could be transported from within the coal mines themselves.  The Duke's brother-in-law was Lord Gower, who owned coal mines and limestone quarries in East Shropshire.  It is thus not surprising that Lord Gower soon constructed the Donnington Wood Canal, the first in Shropshire, to transport materials from his mines to his ironworks.

 

Following the success of the Donnington Wood Canal, Richard Reynolds and his son William decided to build the Ketley and Wombridge Canals to bring coal to their ironworks.  Although small and relatively short lived, the Ketley Canal was a pioneer in the use of the inclined plane.  William Reynolds tends to get overshadowed by the more famous Thomas Telford but in this area he was the prime mover and innovator.  The Shropshire Canal followed soon after to join them all up and to provide a link to the River Severn.  Unlike the previous canals, however, this was operated by a company rather than a partnership.

 

 

Inclined Planes

 

Canal

Name

Opened

Closed

Length

Height

Ketley

Ketley

1788

1816

300ft

73ft

Shropshire

Wrockwardine Wood

1791

1858

960ft

122ft

Windmill

1791

1858

1,800ft

126ft

Hay

1791

1894

1,050ft

207ft

Shrewsbury

Trench

1793

1921

669ft

75ft

Shropshire

Brierley Hill

1794

1800

420ft

150ft

Donnington Wood

Hugh’s Bridge

1797

1879

369ft

43ft

 

Thomas Telford described the Ketley Incline in 1800 “…Mr William Reynolds of Ketley … made a navigable canal, and instead of descending in the usual way, by locks, continued to bring the canal forward to an abrupt part of the bank, the skirts of which terminated on a level with the iron-works. At the top of this bank he built a small lock, and from the bottom of the lock, and down the face of the bank, he constructed an inclined plane with a double iron railway. He then erected an upright frame of timber, in which, across the lock, was fixed a large wooden barrel; round this barrel a rope was passed, and was fixed to a moveable frame; this last frame was formed of a size sufficient to receive a canal boat, and the bottom upon which the boat rested, was preserved in nearly an horizontal position, by having two large wheels before and two small ones behind varying as much in the diameters as the inclined plane varied from an horizontal plane. This frame was placed in the lock, the loaded boat was also brought from the upper canal into the lock, the lock-gates were shut, and on the water being drawn from the lock into a side pond, the boat settled upon the horizontal wooden frame, and as the bottom of the lock was formed with nearly the same declivity as the inclined plane, upon the lower gates being opened the frame with the boat passed down the iron railway, on the inclined plane, into the lower canal, which had been formed on a level with the Ketley iron-works, being a fall of 73 feet.

 

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Very little water was required to perform this operation, because the lock was formed of no greater depth than the upper canal, except the addition of such a declivity as was sufficient for the loaded boat to move out of the lock; and in dry seasons, by the assistance of a small steam engine, the whole of the water drawn off from the lock, was returned into the upper canal by means of a short pump.  A double railway having been laid upon the inclined plane, the loaded boat in passing down, brought up another boat containing a load nearly equal to one-third part of that which passed down. The velocities of the boats were regulated by a brake acting upon a large wheel placed upon the axis on which the ropes connected with the carriage, were coiled.”

 

Two Prussian engineers visited Britain in 1827 and described the construction and operation of the Hay inclined plane.  The rails were made of cast iron, and were "L" shaped in section. The running surface was 7 inches wide by 2 inches thick, while the vertical flange was 2½ inches tall and 1 inch thick. They were described as the strongest and thickest that they had seen.  Most of the incline was laid with only three rails, with a small section in the middle which had four rails, so that the boats could pass one another. Because the flanges were on the rails rather than on the wheels as in modern railway practice, one track had the flanges on the inside, and the other on the outside. The rails were fixed to timbers running along the incline, 14 inches square, which were attached to wooden sleepers which ran across the incline.

 

The boats were made of wood, and were 18 feet long by 5 feet 2 inches wide. They were 2½ feet deep and weighed about 1½ tons, but when loaded with 5 tons of coal or iron, only 3 inches remained above the water. In order to transport them along the incline, they were attached to a simple frame with four wheels, with a diameter of 27 inches at the front and 16 inches at the back. The rear axle carried a second set of wheels, 24 inches in diameter and spaced much wider than the main wheels, which ran on a special track at the top of the incline and prevented the frame from getting stuck when it passed over the hump. These wheels were flanged, unlike the main wheels.

 

The main wheels are described as having an inside gauge of 43 inches, presumably between their inside faces. The engine was a 16” steam engine and was used to draw the wagon and boat over the hump and out of the top pound. It was also used to complete the movement of an ascending boat, which would no longer be counterbalanced once the descending boat entered the water at the bottom. The engine drove a drum 7 feet in diameter, which carried the rope, and which had a clutch mechanism to allow it to be driven by the engine or disconnected from it, as required.

 

 

Boats

 

The standard boat used on canals is termed a “narrowboat”. This is because it should be built no more than 7ft wide to be able to negotiate the locks.  To compensate for this, they are relatively long and can be up to 70ft in length.  As a result, they look narrow and hence the name

 

 

Another development was the smaller tub-boat, which was made of either wood or iron.  It was used on the Duke of Bridgwater’s Canal and thus adopted by Lord Gower for his Donnington Wood Canal.  Since narrowboats would be too big for inclined planes, tub-boats were subsequently adopted for the local canals.  The Shropshire version was square, 20ft long and 6ft 4 inches wide.  Those used on the Ketley Canal could carry 8 tons but those on the Shropshire Canal were not so deep and only carried 5 tons.  They were connected together in trains pulled by a horse and one horse could pull 12 tub boats carrying some 60 tons of coal.  The locks on the Shrewsbury Canal were designed so that four tubs could fit into them.

 

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In 1800, Thomas Telford wrote “… a book has lately been published by an American of the name of Fulton … ‘On viewing the operation of locks, it appears that if they were constructed for small boats, suppose boats of four tons, the delay in passing would be so great, that an important trade would not be transacted, as it requires almost as much time to pass a small as a large boat; for instance, only a man arriving with six four-ton boats (equal to what is usually conveyed in a boat of 25 tons) at a lock constructed for small boats, he would be obliged to separate them, and pass them singly, which would be an operation of three minutes at least to each boat, together with the time necessary for uniting them when passing through, say four minutes, in all amounting to 24 minutes; a repetition of this operation, to mount only 100 feet by 12 locks, would be a delay of 4 hours 48 minutes: this would not only be tedious, but create confusion wherever there was a number of boats passing, even if passing the same way: how this would be increased by those moving the contrary way, may easily be conceived; yet the twenty-five ton boats would move through the first lock in five minutes at the utmost, and passing through the succeeding 11 locks with the same expedition, would rise to the summit-level in one hour: hence the twenty-five ton boats would have an advantage in time, 3 hours 48 minutes. This calculation will sufficiently prove the impropriety of constructing locks for small boats: hence small and cheap cannot be formed on the lock principle. Locks demand large boats, that an important trade may be performed, and large boats are the cause of increasing the expense of all the other parts of the canal, in tunnels, bridges, aqueducts, land, reservoirs, diggings, etc. which evidently exclude every district which cannot support these heavy expenses, and preclude every hope of giving to agriculture and commerce the full force of so powerful an agent as water conveyance.

 

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Thus having roundly stated the time that would be lost in passing the locks with small boats separately, he insists that locks demand large boats, and that large boats, increase the expense of all the other parts of the canal, and likewise that locks are often out of repair, therefore that locks ought, to be totally exploded. But it is a mistake that more time is required to pass locks, with an equal quantity of tonnage, by the small than with large boats, for on the Shrewsbury Canal, four boats, each carrying eight tons, pass a lock at one time; and by that means, with small boats, 32 tons pass a lock in five minutes, whereas a seventy-feet boat would only pass it with from 20 to 25 tons in the same time. If the boat is made 70 feet in length, but of the same width and depth as the small boats, no other part of the canal will require anymore expense than if constructed for small boats only. Locks, it is true, are sometimes out of repair, but being the simplest machines that have yet been made use of in canals, they are less liable to be put out of repair than any of the others, which are all of them more complicated.”

 

 

Thomas Telford on the River Severn in 1800

 

“…The inconveniences attending the navigation of this river, arise chiefly from the following causes, viz.

 

·         the fords and shoals which are frequent in a river, the bed of which has a considerable declivity, and consists of matter of such different qualities.

·         the deficiency of water in drought, and from the superabundance of it during rainy seasons; and,

·         the mode of hauling the barges by men instead of horses.

 

These circumstances, taken together, render the navigation very imperfect; and the year 1796 afforded a striking instance of the degree of this imperfection, since during the whole of that year, there were not two months in which barges could be navigated, even down the river, with a freight which was equal to defray the expenses of working them. This interruption was severely felt by the coal-masters, the manufactures of iron, the barge owners, and the county in general.

 

The inconveniences arising from the irregularities of the water have always existed in. some degree, but they have been greatly increased by the embankments which have lately been raised to protect the low lands in Montgomeryshire, and in the upper parts of the county of Salop. Formerly, when the river had arrived at a moderate height, it overflowed these low lands to a great extent, which thereby operated as a side reservoir, and took off the top waters of the high floods; and these waters returning to the bed of the river by slow degrees, proved a supply for the navigation for a long time after the flood began to subside, but being now confined to a narrow channel, they rise suddenly to a greater height, and flow off with more rapidity than formerly; whereby the navigation is at one period impeded by uncontrollable floods, and, at another, left destitute of a sufficient supply for its ordinary purposes.  To remedy the inconveniences attending the shallows, and the irregularities of the water, two plans have been recommended, the adopting of either of which would greatly improve the navigation.

 

This plan, besides improving the navigation of the river, would enable the proprietors of the adjoining lands to water all the grounds which lay below the level of the locks, and they might likewise build corn-mills corresponding with the falls, with thrashing-mills, and other improved machinery for the purposes of agriculture. Besides the working corn-mills, another, and very important purpose, is the use of the river-water in working iron forges with all their appendages: this great and increasing business is chiefly carried on by means of trifling brooks, often dry in the Summer, and at all times of very inadequate quantity. The water of the river would constantly afford a sufficient power, and the materials for the manufacture, and the markets for consumption, are all to be found on its banks, or connected with its navigation.

 

The second plan is to collect the flood-waters into reservoirs, the principal ones to be formed among the hills in Montgomeryshire, and the inferior ones in such convenient places as might be found in the dingles, etc. along the banks of the river. By this means the impetuosity of the floods might be greatly lessened, and a sufficient quantity of water preserved to regulate the navigation of the river in dry seasons, and likewise to answer many other useful purposes, such as the forming ponds for inland fisheries, the supplying artificial canals, and the watering of land. This, it is thought, might even prove the simplest and least expensive mode of regulating navigable rivers, especially such as are immediately on the borders of hilly countries.

 

With regard to adopting the mode of hauling barges by means of horses, instead of the present barbarous and expensive custom of performing this slave-like office by men, it is only necessary that a good towing-path for horses should be formed along the banks of the river, and which will no doubt take place, if any scheme of general improvements should ever be adopted.”

 

 

Thomas Telford on the Canals in 1800

 

 

“The county of Salop has not been among the first to adopt this valuable improvement, and it is probable that this backwardness ought to be accounted for, from its enjoying the benefit of so fine a river. But the general consumption of the kingdom at large, continuing to create a still greater demand for the products of the county, in mines and manufactures, as well as agriculture, these likewise extending, in the natural progress of improvement, to a greater distance from the river, and the expense of conveyance being thus proportionally increased, it has of late become an object, of importance to improve, by some means, the mode of conveyance from the more distant works to the banks of the river.  The superior utility of navigable canals, had by this time been pretty generally ascertained, and they were found to be more especially advantageous in the removal of heavy articles; it therefore became evident, that a navigable canal was the means by which coal and iron could he sent from such distances as the Oaken Gates and Ketley, so as to reach the market on terms of competition with the same sort of articles which are procured nearer to the river.

 

But how necessary a navigable canal might be for those purposes, it was for a long time deemed an impracticable project. The general summit over which it must pass … there was no prospect of procuring a sufficient quantity of water for the purposes of lockage, the only mode of conveying boats from a higher to a lower canal, which had at that time been tried in Britain.  Although Shropshire was behind most of the other counties in adopting the plan of forming artificial canals, it has of late made a rapid progress in the execution of this valuable improvement; and I may venture to say, that there has been more ingenuity displayed in the means taken for overcoming the various obstacles which lay in the way of the canals of this county, than has hitherto been shewn in those of any other county in England.

 

The inclined planes, the small boats, the ascending and descending by means of pits, with the various machinery connected therewith upon the Ketley and Shropshire Canals, and the iron aqueduct upon the Shrewsbury canal, were each of them new with regard to British canal-making… It has also been proposed to carry a canal from the Marquis of Stafford’s canal at Pave-lane, near Newport, to the town of Drayton, and from thence to the Grand Trunk, at or near to Stone, in Staffordshire. By means of this canal, the North-East part of the county would be better supplied with coal and lime, and a direct water communication would be opened with the Grand Trunk Navigation, an object of considerable importance to all that part of the country, and also to the manufactures in the neighbourhood of Ketley and the Oaken Gates.“

 

 

Tunnels

 

Canal

Name

Opened

Closed

Length

Wombridge

Priory

1788

1921?

?

Ketley

Shepherd’s Lane

1788

1816

20 yds

Ketley Hall

1788

1816

20 yds

Shropshire

Watling Street

1790

1858

50 yds

Snedshill

1790

1858

279 yds

Stirchley

1790

1858

281 yds

Brierley Hill

1791

1794

180 yds

Shrewsbury

Berwick

1797

1944

970 yds

 

Tunnels caused problems for boats since the lack of towpaths meant that in many tunnels the boat crews would have to 'leg' their way through a tunnel. They lay on their backs and pressed their feet on the ceiling to force their way through it.  Berwick Tunnel was the first major canal tunnel in Britain to have a towpath built through it. However, this did not solve the other major problem with long tunnels, particularly those which, like the Berwick Tunnel, were not straight. Conflicts could occur when two boats came at it from opposite directions. To overcome this, a bye-law was introduced which stated that whoever reached the centre first should continue, whilst the 'loser' would have to turn back. At busy periods, a boat might be forced to turn around two or three times.

 

 

Bridges & Aqueducts

 

There are 8 aqueducts and 101 bridges on the Telford canals.  The Longdon Aqueduct is perhaps the most famous, being the first successful cast iron aqueduct in Britain.  The Kynnersley Drive Aqueduct was probably the most attractive looking and it is a shame that it was destroyed.  Some idea of what it looked like can be obtained by visiting the one over the A5 at Stretton 

 

There were 5 types of bridge used.  Wooden drawbridges were used a lot on the Shrewsbury Canal, a deck was hinged to one abutment and suspended at the far end from horizontally pivoted balance beams which had to be pulled down by the use of a rope or chain to raise the bridge. The hinge was placed on the side of the canal away from the towpath so as to provide an unobstructed course for the towlines of the horse drawn boats. The advantage to the canal company of building drawbridges was that it was a far cheaper solution. With the bridge just above water level, the construction work saved was considerable. Materials were not required to build up approach embankments where the canal was on essentially flat land, as in this part of Shropshire, and the span was reduced by dispensing with the need to span the towpath as well as waterway.  There was one swing bridge south of Withington and the rest were either footbridges or stone bridges.  The latter were usually standard design but some were curved “roving bridges” which allowed towing horses to cross over where the towpath changed sides.