Friday, June 16, 2017

"A Scotch job"? - the Caledonian Canal

Neptune's Staircase at Banavie
Today, it's regarded as a national treasure: a jewel in the built heritage crown worthy of millennial and lottery largesse. But in the 1820s the Caledonian Canal was the Edinburgh Trams of its day - over budget, behind schedule and nowhere near living up to original expectations. At least the capital's trams have never posed a danger to anybody but in the 1830s there was a risk that, due to poor workmanship, the Caledonian Canal could have caused flash flooding with the potential for massive damage to property and loss of life: the canal was under such a dark cloud that decommissioning the whole thing was seriously considered.

I hadn't planned to write about the Caledonian Canal. It's one of these things that's just so sort of big and ubquitous (like St Kilda and the Waverley) that I'm not as interested in it as I should be. But the discovery that the canal has a chequered past piqued my interest. And it shows there's nothing new under the sun when it comes to Government prevarication over large engineering projects (think third runway at Heathrow) or trying to get things done on the cheap via privatisation. This is the story.

The Caledonian Canal at Fort Augustus - Copyright Canmore

The earliest mention of a canal through the Great Glen seems to have been in the 1730s when Edward Burt, an army officer stationed at Inverness and author of "Letters from a Gentleman in the North of Scotland to his Friend in London", mentioned "several projects" for a canal (Letter XXVI). In 1773, the Trustees of the Forfeited Estates (properties confiscated from people involved in the Jacobite Risings) commissioned a survey from James Watt who at the time was earning a living in civil engineering while waiting for his groundbreaking inventions in the field of steam engineering to bear fruit. Watt reported favourably but the idea was not taken up. Nor was anything done following a further survey in 1793 by the designer of the Crinan Canal, John Rennie, for the British Fisheries Society (which had established the villages of Tobermory and Ullapool). It was not until Thomas Telford's report of 1803 described in my last post that the Caledonian Canal was at last progressed and work commenced the following year.

It wasn't just local traffic (e.g. fishing boats passing between Moray Firth ports and the fishing grounds off the west coast) the Caledonian Canal was planned to accommodate. Not only did international traffic (sailing ships in these days, of course) between the Baltic and ports in the north west of the British Isles such as Liverpool, Dublin, Glasgow and Belfast have to run the gauntlet of the Pentland Firth between Caithness and Orkney with its contrary winds and ferocious tidal currents, so too in the pre-railway era did any load bigger than could be slung over the backs of a train of pack horses which had to be moved from coast to coast within Great Britain - a cargo of Ballachulish slate for Dunbar, for instance, or salt from Liverpool to Banff. The Forth & Clyde Canal had opened in 1790 but, crucially, it was not big enough to accommodate sea-going vessels: cargoes had to be trans-shipped into canal barges (known as "lighters": later in the 19th century these were equipped with steam engines and began to sail outside the canal known as "puffers") with consequent delay and expense. But the Caledonian Canal was conceived on an altogether grander scale to allow the largest sea-going vessels through. When work began in 1804, Telford estimated it would take seven years and cost £475,000 to complete.

By the time seven years had passed, in 1811, the canal was still a long way from complete. In fact, the central section, from Loch Ness to Loch Lochy, hadn't even been started yet so it was hardly a surprise it was still unfinished two years later when the estimate of £475,000 was exceeded. In fairness, the cost of labour and materials had soared during the first decade of the 19th century due to the Napoleonic Wars but it's probably also the case that there just wasn't enough practical experience of such large projects to be able to estimate them accurately. There were also formidable engineering challenges of which it will suffice to mention just one - the sea lock at Clachnaharry where the canal enters the Beauly Firth at Inverness pictured below.

The sea lock had to be placed so far out from the natural shoreline to find deep enough water because the bed of the firth deepened at such a shallow angle. As the embankments out from the shore towards the site of the sea lock were being built, they were discovered to be sinking under their own weight into the soft mud of the seabed: how on earth would it support the weight of the masonry of the lock itself? The solution hit upon was to carry earth out from the shore and pile it up in a mound where the lock would go. The stone for building the lock was then piled on top of this mound and it was left to settle and find its natural level. This proved only partially successful, however, for it was discovered some years after the lock had been built that it had sunk by 18 inches! The only saving grace was it had all sunk at the same rate so at least there was no distortion or cracks in the structure.

In 1822, now 11 years behind schedule and with nearly twice the original estimate having already been spent, the locks were mostly all finished but there was still much work to be done on the canal itself to achieve the planned depth of 20 feet to accommodate the largest seagoing ships. In some places this involved further excavation while in others it involved the expensive process of "puddling", that is, lining the banks with waterproof clay to prevent the water leaking out through porous soil. With the canal already being denounced by its detractors as "a Scotch job" (job in the archaic sense of a dodgy political deal: pork barreling we'd call it nowadays), Parliament was exasperated to be told it was going to take another £37,000 to finish, exclusive of unquantified claims from landowners for land take and damage to amenity etc. With the return of peace after the Battle of Waterloo in 1815, some of the factors which had led to the canal being sanctioned at public expense (employing potential cannon fodder to prevent it from emigrating and protecting shipping from enemy attack) had disappeared. Faced by calls to abandon it altogether, the legislature sanctioned only another £25,000 to complete the canal to a depth of just 12 feet rather than the 20 feet originally planned. And so, in this attenuated state, the Caledonian Canal finally opened for traffic from sea to sea in October 1822.

Key locations on the Caledonian Canal

But still the haemorrhage of public money continued. Attracting only a tiny fraction of the anticpated traffic (in 1838 it was estimated the canal was attracting only a fortieth of the traffic going "northabouts" through the Pentland Firth), it couldn't even cover its maintenance costs. And it wasn't long before the canal works began to deteriorate due to the skimped workmanship carried out in the latter phases of construction in a desperate attempt to keep costs down.

Matters came to a head in December 1837 when one of the locks at Fort Augustus collapsed. The beleaguered Canal Commissioners reported this to the Treasury in London along with their concerns about the potential for a far more serious accident due to the state of the canal south of  Loch Lochy. On the stretch known as the Banavie Reach between the lock at Gairlochy at the south west end of Loch Lochy and the top of the flight of eight locks at Banavie known as Neptune's Staircase, there were several culverts (acqueducts) carrying the canal over streams coming down off the hills to the west. The condition of these culverts was giving cause for concern: if any of them collapsed, the threat was not just that all the water in the Banavie Reach would flood out (which was bad enough) but that, due to the defective masonry they were mounted on, the gates of the lock at Gairlochy, deprived of the counterweight of the water in the canal below them, would not be able to hold back Loch Lochy (the level of which had been raised by 12 feet during the course of construction of the canal). If these gates failed, the waters of the loch would gush out in a torrent which would not stop until the loch had drained down by 27 feet (i.e. the vertical distance between the level of Loch Lochy in a flood and the bed of the canal below), a release of about 13 million cubic metres of water with the potential to cause immense damage and, possibly, loss of life.

One of the troublesome culverts on the Banavie reach

The Treasury responded to these concerns by commissioning Thomas Telford's successor as President of the Institution of Civil Engineers, James Walker, to report on both the works immediately necessary to make the canal safe and those desirable to make it viable in the longer term. In the short term, Walker recommended the insertion of a second lock at Gairlochy and work to improve run-off from Loch Oich costing a total of £17,000. To make the canal viable in the longer term, he recommended that it be deepened to 17 feet (he didn't consider the originally planned 20 feet worth the extra cost), principally by additional excavation and puddling (waterproofing) to prevent the water in the canal leaking away at the rate of nearly 700 cubic metres a minute as it did from the Muirtown Reach: with various other works, including radical surgery on some of the locks, this was all estimated to cost £104,490.

Walker's report was referred to a select committee of the House of Commons. By now the question was whether to complete the canal in accordance with Walker's recommendations or abandon it altogether: patching it up to enable it to limp along attracting such a tiny fraction of its potential traffic was no longer an option. After hearing that the cost of demolishing the canal could be almost as much as completing it, the Committee reported in August 1839 that it had no hesitation in recommending that the canal be completed to 17 feet depth in accordance with James Walker's report. This was despite the fact that, due to further deterioration of the canal works in the interim and in light of the history of consistent under-estimation of costs associated with the Caledonian Canal, Walker had advised the committee to be prepared for a total outlay of up to £200,000.

A ship being towed along Loch Oich by its own boat in 1836

You can read the Select Committee Report here. James Walker's Report is Appendix 1 and also worth reading is a report on the canal and its history by its resident engineer, George May, which is Appendix 3. They all highlight another huge problem with the Caledonian Canal, greater even, perhaps, than its inadequate depth and collapsing masonry: the three lochs - Ness, Oich and Lochy - which make up nearly two thirds of its length. The feature which appeared to make construction of the canal feasible by nature having already built so much of its length was actually its greatest weakness in the age of sail. This was because the wind blows either up or down the Great Glen but never across it: a sailing ship can't sail into the wind and a tow path to enable one to be towed upwind by horses can't be built along the shore of a loch as it can along the banks of artificial cuttings. Ships entering the canal, therefore, regularly had to wait for weeks for a fair wind completely negativing any time advantage over sailing "northabouts" through the Pentland Firth. This syndrome had been apparent even to Edward Burt back in the 1730s ("would render the navigation so precarious that hardly anybody would venture on it" he said) and it's something of a puzzle why it eluded Thomas Telford but, fortunately, by the 1830s technological progress had intervened to provide a solution: steam tugs. These would enable a sailing ship to pass through the canal in just three days, even against an adverse wind, a considerable saving on the passage "northabouts". Provision of steam tugs, therefore, formed a key part of Walker's recommendations.

Not on the Caledonian Canal but the most famous steam tug of all - that depicted in Turner's 1839 classic "The Fighting Temeraire"

The Government's response to the Select Committee report was to try to privatise the canal: an Act of Parliament passed in August 1840 authorised it to lease the canal for up to 99 years at a peppercorn rent to a private operator who would undertake the improvements. But there were no takers and, before committing another six figures of taxpayers' money, the Government decided it wanted to hear the opinion of a mariner (as opposed to a civil engineer) on the vital question of whether, if the canal were completed to Walker's specifications, it would actually be used. The task was entrusted to Arctic explorer Captain Sir Edward Parry, RN. As well as inspecting the canal itself, Parry covered 1,600 miles visiting ports from Liverpool round to Hull gathering evidence from over 100 merchants, ship owners and seafarers. He submitted his report in January 1842. You can read it here. Noting the canal's present "wretched state of inefficiency", the man who had braved polar winters in pursuit of the North West Passage echoed Burt by observing: "I could not help wondering not that so few had ever availed themselves of this navigation, but that any had ever been bold enough to attempt it".

That said, Parry's conclusion was that, if duly improved (principally by deepening to 17 feet, the provision of steam tugs and various other improvements listed in Appendix 118 to his report), the Caledonian Canal would provide a quicker, safer and therefore cheaper passage than going "northabouts": Parry reckoned on an average saving of nine and a half days and - taking into account factors such as lower insurance - a financial saving of the order of £40 (about £4,000 in today's money) per passage for a 300 ton ship even if the canal dues were doubled. This being so, he believed it would be used by a large proportion of the ships going through the Pentland Firth and perhaps even by some going from west to east by the English Channel.

The Government appointed another Select Committee to consider Parry's report. This reported in May 1842 by endorsing the 1839 Committee's conclusion that the works on the canal should be proceded with. But then, in the winter of 1843 while the Government continued to dither, the long anticipated disaster at Loch Lochy was avoided by the merest stroke of good fortune. In January, a portion of masonry at the lower lock gates at Gairlochy failed during a storm. Fortunately, the upper gates held but urgent repairs had to be undertaken in atrocious conditions involving building a temporary dam across the canal to hold the loch back (which at its highest reached 2' 6" above the level of the lock gates) while work was carried out on the lock. The work was completed in February leaving the lock in a sounder condition than it had been for many years. Which was just as well because in March, one of the culverts on the Banavie Reach collapsed and all the water in the reach emptied out. If that had happened before the Gairlochy lock had been strengthened, it would almost certainly have failed with catastrophic results.

Plan from the Canal Commissioners' 16th Report (1819) showing the vulnerable lock at the foot of Loch Lochy. The canal occupied the bed of the River Lochy which was redirected into an artificial cut draining into the River Spean.

The scare appears to have galvanised the Government into action for in August 1843 it at last gave the go ahead to complete the canal and a contract was let for £136,089 to carry out the improvements recommended by James Walker over a period of three years. Work began in September and, this time, was completed only seven months behind schedule (and a mere £22,500 over budget) and the Caledonian Canal reopened from sea to sea, complete with two steam tugs (with another two on order) on 1 May 1847.

But it was too late. Despite some promising early signs, the canal never captured the volume of trade it had been designed to accommodate. The reason again was steam power which, from being the canal's saviour in the shape of steam tugs, soon became its enemy attacking it on two fronts. Firstly, from their beginnings in 1812 through the second quarter of the 19th century, steamships had been confined to niche short range applications (such as tugs and ferries) while cargos and long distances continued to be the domain of the sailing ship: this was simply because ships of typical early 19th century size couldn't carry enough coal to take a heavy load very far. But that changed in the second half of the century with the advent of larger, iron steamships, too big for even the Caledonian Canal's generously sized locks and for whom a passage northabouts through the Pentland Firth held no fears anyway. Secondly, the rise of the railway from the 1840s took away much of the coast to coast trade. (Parry had actually considered the issue of railways in his report but concluded they didn't pose a threat to the canal. He was proved wrong.) And so the canal's traffic came to be confined largely to fishing boats and smaller, local coasters. In 1860, another attempt at privatisation failed while in 1868 the costs of decommissioning were looked into by the engineer later to be responsible for the Forth Bridge, Sir John Fowler, and estimated at a £1,000,000 (about a Billion Pounds in today's money). "Practically obsolete" was how witnesses described the canal to a 1906-09 Royal Commission on Canals and Waterways which refused to endorse any public expenditure on schemes to enlarge it. Whether or not it was a "Scotch job", the Caledonian Canal was destined always to be a white elephant.

An early 20th century proposal for enlarging the canal superimposed on an actual cross section. Unsurprisingly, it was not taken up.