Sapperton Canal Tunnel
|The Coates Portal at the south-eastern end of the Sapperton Canal Tunnel|
|OS grid reference||SO955019|
|Waterway||Thames and Severn Canal|
|Opened||20 April 1789|
|Length||3,817 yards (3,490 m)|
The Sapperton Canal Tunnel is a tunnel on the Thames and Severn Canal near Cirencester in Gloucestershire, England. With a length of 3,817 yards it was the longest canal tunnel, and the longest tunnel of any kind, in England from 1789 to 1811.
Although the Thames and Severn Canal was authorised by an Act of Parliament on 17 April 1783, the details of the tunnel had not been worked out, and arguments about its size continued for two or three months. Boats on the Severn were trows and were 15 feet (4.6 m) wide, while those on the Thames were Thames barges, which were 12 feet (3.7 m) wide. The only long tunnel in the country at the time was Harecastle Tunnel, which was suitable for narrow boats just 7 feet (2.1 m) wide. A party of Commissioners from the Thames thought that the cost of a wide tunnel would be prohibitive, and that it should be built for narrow-beam boats, with the trows or barges unloading their cargos at each end of the tunnel.
By late summer, the decision had been taken to build a broad tunnel, 15 feet (4.6 m) high and 15 feet (4.6 m) wide, and the company advertised for tunnellers in September. The tunnel would be 3,817 yards (3,490 m) long, and was expected to take four years to complete, beginning in early 1784. In order the speed the work, 25 shafts were sunk along its length, to provide multiple workfaces, the deepest of which was 244 feet (74 m). The construction contract was awarded to Charles Jones, who managed to build about one third of it, but then had financial difficulties, and so a number of other contractors were engaged to work on smaller sections of it.
The tunnel was opened on 20 April 1789 after five years of construction. It has no towpath; boats were propelled through the tunnel by legging. There were some defects in the workmanship, as it had to be closed for ten weeks after only a year, while repairs were carried out.
It was superseded as the longest canal tunnel in England in 1811 by the Huddersfield Narrow Canal's Standedge Tunnel, which was 5,456 yards (4,989 m) long when built, later extended to 5,698 yards (5,210 m) to accommodate the adjacent railway tunnel, and remains the highest, longest and deepest canal tunnel in Britain - though, unlike Sapperton, Standedge can only accommodate 7-foot-wide narrowboats (2.1 m). Strood Tunnel on the Thames and Medway Canal was also longer at 3,946 yards (3,608 m) when it opened in 1824, but was cut in two in 1830 by opening out a short section to create a passing basin.
Sapperton Tunnel is not currently navigable as the roof has collapsed over several hundred yards, mainly in sections where the ground is fuller's earth, but restoration is proposed by the Cotswold Canals Trust as part of their project to re-open the canal route from Thames to Severn. The trust operates tourist boat trips into the tunnel in winter months.
There have been proposals for a national network of canals and aqueducts to bring water from the River Severn toward the Thames Basin and London; if such a plan is realised the Sapperton Canal Tunnel could be utilised to transport water.
The Tunnel in Fiction
In Hornblower and the Atropos by C.S. Forester, Hornblower helps the boatman "leg" through Sapperton Tunnel after the boatman's assistant is incapacitated. Forester spends the first two chapters of the book on the canal-boat journey, Roughly a third of the first chapter is devoted to the tunnel.
(links to map & photo sources)
- Hadfield 1968, pp. 316–317
- Hadfield 1968, pp. 317, 319
- "Thames and Severn Canal".
- Hadfield 1968, p. 319
- Hadfield & Biddle 1970, p. 323
- Hadfield 1968, pp. 90, 94
- "Sapperton Canal Tunnel". Cotswold Canals. Retrieved 2014-01-30.
- Black, Richard (20 February 2012). "Drought summit: Why not pipe the water from north to south?". BBC News. Retrieved 20 February 2012.
- McKnight 1981, p. 145
- Excerpt from Hornblower and the Atropos
- Forester, C. S. (2006). Hornblower and the Atropos. Penguin. ISBN 978-0-14-102504-9.
- Hadfield, Charles (1969). The Canals of South and South-East England. David and Charles. ISBN 0-7153-4693-8.
- Hadfield, Charles; Biddle, Gordon (1970). The Canals of North West England, Vol 2 (pp.241-496). David and Charles. ISBN 0-7153-4992-9.
- Hayder, Mo (2010). Gone (Jack Caffery Thriller). Bantam. ISBN 978-0-553-82433-9.
- McKnight, Hugh (1981). The Shell Book of Inland Waterways. David & Charles. ISBN 0-7153-8239-X.