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Glasgow, Monkland Canal, Blackhill Locks And Incline

Canal (18th Century), Inclined Plane (19th Century), Lock(S) (18th Century), Lock(S) (19th Century)

Site Name Glasgow, Monkland Canal, Blackhill Locks And Incline

Classification Canal (18th Century), Inclined Plane (19th Century), Lock(S) (18th Century), Lock(S) (19th Century)

Alternative Name(s) Craigendmuir Street; Blackhill Locks And Incline

Canmore ID 169687

Site Number NS66NW 273

NGR NS 6270 6641

NGR Description NS 6291 6652 to NS 6248 6628

Datum OSGB36 - NGR


Ordnance Survey licence number 100057073. All rights reserved.
Canmore Disclaimer. © Copyright and database right 2018.

Digital Images


Administrative Areas

  • Council Glasgow, City Of
  • Parish Glasgow (City Of Glasgow)
  • Former Region Strathclyde
  • Former District City Of Glasgow
  • Former County Lanarkshire

Archaeology Notes

NS66NW 273.00 6291 6652 to 6248 6628

Monkland Canal (Disused) [NAT] (at NS 6277 6653)

Blackhill Locks [NAT] (at NS 6262 6650)

OS 1:1250 map, 1954.

NS66NW 273.01 NS 6289 6649 Upper terminus and dock

NS66NW 273.02 NS 6287 6652 Upper double locks

NS66NW 273.03 NS 6269 6653 East central locks

NS66NW 273.04 NS 6255 6644 West central double locks

NS66NW 273.05 NS 6250 6631 Bottom double locks

NS66NW 273.06 NS 6278 6653 No. 1 basin

NS66NW 273.07 NS 6261 6651 No. 2 basin

NS66NW 273.08 NS 6254 6636 No. 3 basin

NS66NW 273.09 NS 6246 6627 Lower Reach (basin)

NS66NW 273.10 NS 6291 6650 Upper Reach, footbridge

NS66NW 273.11 NS 6273 6644 Inclined plane, upper footbridge

NS66NW 273.12 NS 6268 6640 Inclined plane, central footbridge

NS66NW 273.13 NS 6276 6646 to NS 6250 6627 Inclined plane

NS66NW 273.14 NS 6248 6625 Inclined plane, lower footbridge

NS66NW 273.15 NS 6244 6624 West footbridge

NS66NW 273.16 NS 6262 6646 Inclined plane, engine-house

The level of the canal is raised by 96 feet [29.7m] at Blackhill, using eight locks. These locks, although not completed, are 'in great forwardness.'

OSA 1793.

In order that coal barges could traverse the whole length of the canal, the two sections needed to be linked by these locks at Blackhill, where there was a difference of 96 feet in the water level. An estimate of their cost in 1790, made by the civil engineer Robert Whitworth, was 3, 982 pounds sterling. The locks took a considerable time to construct, not being finished until 1794. In order to overcome the 96 feet drop, Whitworth planned four double locks, 'each double lock having two falls each of 12 feet in one range of building.' However, the higher level of pressure created by this design of locks as opposed to single locks created a problem of expensive repairs for many years.

In 1832, Andrew Thomson, a Glasgow Civil Engineer, suggested that, to cope with the increased volume of traffic through the locks, an inclined plane (NS66NW 273.13) should be built to convey empty boats. This idea was shelved, resurrected by James Leslie, another Glasgow engineer, in 1839, this time using a dry cradle instead of floating them up, as Thomson had originally sugested. However the Company Committe decided in 1841 to duplicate the locks instead. In 1839 two new double locks at the upper level parallel to the old ones, which were in a bad state of repair, had been built (NS66NW 273.02). The cost had been 8000 pounds sterling incuding gates and sluices. In 1841 the old locks at the highest level were completely rebuilt, new ones constructed at the lower levels (NS66NW 273.02 to NS66NW 273.05), the basins (NS66NW 273.06 to NS66NW 273.08) between the locks enlarged and a new graving dock was added at the upper reach (NS66NW 273.01) to replace the one in the lower reach (NS66NW 273.09) which had been removed to make way for new locks. The total cost of these works was approximately 30,000 pounds sterling. However, by 1849 it was realised that the inclined plane was necessary and work to build it was completed by the end of July 1850. It was only used during the six or seven moths in the year when water to cope with the volume of traffic was likely to be in short supply, and was utilised for about 37 years until the volume of traffic on the canal had dropped to a level which could be catered for by the reservoirs.

G Thomson 1945.

The Blackhill Locks were planned in 1785 for the purpose of linking the upper and lower reaches of the canal. Between 1796 and 1798 a sluice and tunnel were constructed for the Forth and Clyde Canal to carry water from the head to the foot of the Blackhill Locks. The locks, consisting of four staircase pairs, furnished a rise of 96 feet. The locks were 30 feet wide at the surface decreasing to 15 feet at the bottom.

In 1837 a suggestion was accepted by the Company to add two new staircase pairs alongside the existing upper ones, which were in a poor state of repair. However, as increase in traffic was so rapid it became apparent that a single line of locks was insufficient and in 1841 it was decided to rebuild the two old upper pairs and construct two new pairs next to the old lower ones. Thus a complete double line was achieved. Contemporaneously, the intermediate basins were enlarged and, as the graving-dock on the lower reach had been removed, a new one was constructed on the upper reach.

As the boats going W into Glasgow with coal and iron were carrying seven eighths of the canal's trade, a majority of the traffic ascending the locks was empty. Therefore, it seemed sensible to build a 6,500 pounds sterling inclined plane at Blackhill to carry these vessels. Such a construction would also act to conserve water. The inclined plane was finished by August 1850 and remained in operation until about 1887.

J Lindsay 1968.

Blackhill Locks and Incline, Craigendmuir St: built 1793 and rebuilt 1841. This flight of four locks was demolished in 1954, and the canal piped. From 1850 to 1887 the locks were supplemented by an inclined plane, on which ran a pair of caissons. The course of the incline can still be seen.

J R Hume 1974.

By 1783 two sections of the canal had been cut, but, due to lack of money to pay for locks at the junction at Blackhill, a cumbersome arrangement of lowerinfg coals into wagons to take them a quarter of a mile on rails downhill to another barge at the base was at the time the only solution. This, however, was not an economical solution long-term. However, the remaining owners of the canal, the Stirling brothers, financed the four staircase pairs of locks, with intervening basins, each lock having a drop of 12 feet, each pair 24 feet. This catered for the 96 feet drop. The first proposal for an inclined plane to deal with the increasingly heavy volume of traffic noted by the early 1830s was rejected. A double set of staircase pairs was completed in 1841, but by 1849, with an ever increasing volume of traffic and associated problem of water supply, it was decided to adopt the idea of an inclined plane.

The locks were still in a reasonabe operating state in the 1950s. The chambers were very deep, with the canal having a 5 feet operating depth. Between the locks and the inclined plane was a towpath, bridges being required to take it over the entrances to the plane. A boatyard, which had been moved from the foot of the locks in the 1840s was still in operation in the 1950s, located with a graving dock on the arm of the canal leading to the plane.

G Hutton 1993.

This flight of locks at Blackhill, comprised four successive staircases, each having two locks. In order to handle the increasing traffic on the canal, the flight was duplicated in the early 1840s. However, by the end of the 1840s, as up to sixty boats per day were using the locks in each direction, there was need to supplement the facilities further. To increase the speed of the traffic and to save water it was decided to construct an inclined plane. This came into use in 1850, but the need for it declined as canalside collieries became exhausted and the railway network was expanded, and it ceased operation about 1887.

P J G Ransom 1999.

This set of locks, associated basins and inclined plane are clearly shown on the 1st edition of the OS 6-inch map (Lanarkshire 1865, sheet vi) and on the 2nd edition of the OS 6-inch map (Lanarkshire 1896, sheet viNE).

In the North Lanarkshire Archives, Cumbernauld (Gazeteer of Scotland, Volume II, p. 437), is the information that two chambers, each 71 feet in length from the gates to the sill and 14 feet in breadth, connected the upper and lower levels of the canal at Blackhill.

Information from RCAHMS (MD), 24 January 2002.


Project (2007)

This project was undertaken to input site information listed in 'Civil engineering heritage: Scotland - Lowlands and Borders' by R Paxton and J Shipway, 2007.

Publication Account (2007)

The growth of Glasgow’s industries and population in the 18th century created a demand for coal and iron which led to a proposal for a canal without lockage on two levels linking the city with the Monklands collieries. In 1770 an Act was passed for its creation and work was planned and executed under the direction of James Watt from 1769–73. The canal was 35 ft wide and 5 ft deep.

In ca.1788 a set of locks consisting of four double locks 75 by 14 ft, each having two lifts of 12 ft, was constructed at Blackhill to obviate double-handling of cargos and two locks were built at Sheepford, extending the canal two miles to Woodhall. The canal was connected to the Glasgow Branch of the Forth & Clyde in 1791. The engineer was Robert Whitworth.

The coal traffic proved so great that the Monkland became Scotland’s most profitable canal. But even the building, in 1841 at Blackhill, of a second set of four double locks, acting independently of the first and costing above £30 000, could not pass boats without unacceptable delay in 1849 because of water shortage.

The problem was resolved by the installation in 1850 of a state-of-the-art inclined plane to the design of James Leslie costing £16 500. It was 1040 ft long with a 1 in 10 gradient. Each boat was conveyed afloat in an iron caisson with traction by means of 2 in. diameter wire ropes and two 25 hp high-pressure steam engines. Until its closure in 1887, boats ascended the incline in about 10 minutes compared with up to 40 minutes via the locks.

R Paxton and J Shipway 2007

Reproduced from 'Civil Engineering heritage : Scotland - Lowlands and Borders' with kind permission of Thomas Telford Publishers.


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