Watson’s Double Canal Boat

From the late 1820s to the late 1840s, the City of Dublin Steam Packet Company [initially as the Inland Steam Navigation Company] carried cargo and passengers across Ireland, from the western end of the Shannon estuary to the port of Dublin, from which it operated a fleet of steamers to Liverpool and elsewhere.

The company operated up to three steamers on the Shannon Estuary, with a regular route from Kilrush, near the western end on the northern side, via Tarbert, on the southern side, to Limerick at the upper end of the tidal Shannon.

From there, the Limerick Navigation, about twelve Irish miles long [roughly 15 statute miles, 24 km], bypassed a series of falls in the river totalling about 100 ft [30.48 m]. The company, which effectively controlled the navigation, carried passengers and cargo on it, in separate boats. There were some experiments with steam but most boats were horse-drawn.

The upper end of the Limerick Navigation was at Killaloe, from which the company operated steamers conveying passengers, and towing cargo in barges, up the 23.5 miles [37.8 km] of Lough Derg to Portumna and then another 14.7 miles [23.6 km] in the River Shannon to Shannon Harbour.

From there, the Grand Canal ran 81.9 miles [131.0 km] to the sea lock and junction with the River Liffey in Dublin. The company’s cargo boats were towed by horse; the Grand Canal Company operated a fast horse-drawn passenger service. The Royal Canal offered a second link to Dublin, from a point 47.2 miles [76 km] further up the Shannon, but the company rarely operated that far north.

Cargoes could thus be conveyed all the way from Kilrush to Liverpool entirely by the City of Dublin Steam Packet Company [CoDSPCo]; passengers could travel from Kilrush to Shannon Harbour, and from Dublin to Liverpool, in the company’s care but were conveyed by the Grand Canal Company along its own canal. Passengers had the benefits of steam on the Shannon Estuary, on Lough Derg and the River Shannon and on the Irish Sea, but were hauled by horse on the Grand Canal and the Limerick Navigation.

Watson and his patents

William Watson managed the inland department of the City of Dublin Steam Packet Company (and later became its Chairman and Managing Director). In March 1838 Watson patented[1]

an improved boat or vessel to be used on canal and other inland navigations.

And in 1839 he patented[2]

an improvement in the construction of ships, and which improvement is also applicable to all kinds of sea-going vessels; and also certain improvements in the construction of boats and other vessels intended to be used on canals and inland navigations.

The second of these seems to have been for a composite ship, a vessel with iron ribs but wooden planking; John Jordan of Liverpool developed the idea in 1849 and it was used in several clipper ships[3].

Composite barges

The Mechanics’ Magazine discussed both inventions in December 1839[4]. It said that a composite ship “of about 160 or 170 tons register” was about to be laid down by the Liverpool shipbuilders Messrs Wilson; Thomas “Frigate” Wilson of Cork had built several vessels for the City of Dublin Steam Packet Company[5]. It was expected to carry more, but draw less, than a conventional vessel, as well as reducing the cost to the builder of carrying large stocks of costly timber while it seasoned: British oak frames were becoming hard to find at almost any price.

The Mechanics’ Magazine also said that

Three canal barges have already been built upon Mr Watson’s plan of construction, of 60 tons burthen each, and with eminent success.

The size, and Watson’s job, suggest that these were for the CoDSPCo’s Irish inland operations, but there is no information about where they were built.

The improved boat or vessel

The Mechanics’ Magazine gave rather more information about Watson’s “improved boat or vessel to be used on canal and other inland navigations” and even provided some diagrams:

Mr Watson’s principal improvement in boats for inland navigation consists in constructing them in such manner, as that they may be temporarily shortened whenever occasion requires, and be thus enabled to pass through lock-chambers of less length than the boats themselves are when fully extended.

There were two different designs. With the first, the two ends of the boat were folded back alongside the main part of the hull but were not detached. All of the sections were watertight.

The Mechanics’ Magazine pointed out that

[…] the lock chambers must be of at least double the breadth of the boat, in order to afford room for bringing the separate parts side by side.

Clearly, wide areas would be needed outside the lock chamber to enable the ends to be swung on their hinges.

The second design was more straightforward, consisting of just two sections, connected by coupling links and bolts and then separated for passing through locks.

The Mechanics’ Magazine said that

Mr Watson’s plan for shortening canal boats is of more importance in Scotland and Ireland, where canal travelling is carried on to a greater extent, than is [sic] England; here railways bear the palm as the means of transit both for goods and passengers.

The intention

The Mechanics’ Magazine returned to the subject in 1841, with a brief notice in November and an article, reproduced from Saunders’s News Letter, in December.[6] The article reported on trials of the boat and also provided background information on Watson’s intentions. Further information was provided in 1866 by Robert Mallet, contributing to a discussion at the Institution of Civil Engineers[7].

The original account in the Mechanics’ Magazine of 1839 said nothing about the propulsion of the canal boat, but Saunders’s News Letter said that it was to be a steam boat. Mallet, who had helped to introduce Scottish-style horse-drawn fly-boats on both the Royal and the Grand Canal, said that he was asked “to adapt steam power and paddle wheels to this boat, in place of horse power”, which suggests that it was originally designed as a horse-drawn boat.

Saunders’s News Letter said that the boat was intended for use on the Limerick Navigation, between Limerick and Killaloe, “the only point [on the Shannon] where the circumstances of the navigation have hitherto prevented the use of steam vessels”. Mallet, however, said that it was for use on the Grand Canal:

[Watson was] thus interested in improving the passenger boats on the canals in the hands of the Canal Companies, and of ascertaining how far this could be effected by the substitution of steam power for that of horses. […] The conditions of the problem were, that if a speed of about 8 miles an hour [12.9 km/h] could be obtained, with a cargo of sixty passengers and their luggage, so that the journey from Dublin to Shannon Harbour could be made in one day, it would be a success; and it was believed it would then answer commercially.

As the CoDSPCo carried passengers on the Limerick Navigation, which it controlled, it seems likely that the boat was intended, at least originally, for use on that navigation. Furthermore, the company had, by 1840, already had three years’ experience of operating an innovative vessel, the Nonsuch horse-drawn iron passage boat, on that navigation[8]:

[…] a sheet-iron boat, 80 feet [24.4 m] long and 6 feet 6 inches [2m] wide at midships, having the stem and stern ends (each 10 feet [3.0] long) attached by strong hinges to the body, and susceptible of being rapidly raised to a vertical position by means of winches; thus reducing the length to 60 feet [18.3] when required to pass through a lock. […] The weight of one man at each end is amply sufficient to keep down the ends when the boat is in motion.[9]

The whole of that 60 feet [18.3] was available for carrying passengers:

The boat thus constructed has been found to answer perfectly; the buoyancy is equal to that of the Scotch boats of similar dimensions; no crankness or unsteadiness accrues when the ends are raised; it is capable of carrying 60 passengers, travelling at a speed of 9 miles per hour, with the same power that was required to draw a 60 feet boat with a less load, and there is a much less action on the canal bank in consequence of the increased length, which at the same time imparts stiffness, and enables passengers to enter and leave the boat with safety. Considerable time is saved in passing the locks, by the opposition of the square end when the bow is raised; the boat may thus be run almost at full speed into the lock, and both ends being raised simultaneously, it is stopped much more easily than if the tapered ends were down.[10]

Saunders’s News Letter said that the company wanted to introduce

[…] a steam-boat of larger dimensions, giving greater comfort and accommodation to passengers, with greater safety, and capable of being wrought at less cost than the fly-boat. Until, however, a recent period, the many obstacles that beset the difficult problem of steam navigation on narrow canals had precluded the possibility of this.[11]

The boat

The Saunders’s description of the boat matches that of Watson’s separable design, so presumably (but not surprisingly) the hinged version was discarded. Saunders said that the boat was 120 feet [36.6 m] long and that, when divided, the two sections could pass side by side through a lock 70 feet [21.3 m] long. Mallet said that the boat’s beam was five foot nine inches [1.8 m].

Separating and rejoining the sections took two men only 40 seconds, using …

[…] a peculiar construction and mechanism of great simplicity, which is such that whatever be the difference of draught in each when separate, they are brought to an equal immersion when rejoined, and in fact become one rigid and firm boat.[12]

The forward section accommodated 60 passengers and up to one hundred weight [50.1 kg] of luggage each. It was wider than a fly-boat, allowing for more comfortable cabins. At the time the article was written, the boat was “receiving her cabin furniture and fittings”; the trials were made using ballast to the expected weight of the passengers.

The rear section carried two 30 hp non-condensing steam engines, with a tubular (locomotive) boiler, the whole weighing less than five tons [5.1 metric tons]. Mallet said that they were high-pressure engines, capable of being wrought up to 40 hp.

The boat had two paddle wheels, using modified versions of the oval float-boards patented by George Rennie, which dipped point first into the water; Mallet said that they “were then believed to possess some peculiar properties in going easily into the water and lifting very little of it.” The helmsman steered using a wheel on deck between the paddle wheels and over the engine room, which gave him a good view, and there was a rudder …

[…] of a peculiar construction, placed beneath the keel of the boat, to prevent injury by grounding on the sloping banks of the canal.[13]

Mallet was less complimentary about the design:

The boat was of such extremely small beam […], so crank and so flimsy in build, that there was great difficulty in putting adequate power into her, or in obtaining sufficient foothold for machinery in a boat of such length, built of half-inch oak planking. […] The weights were distributed, by the aid of longitudinal trussed keelsons, over as large a floor as possible, to enable the boat to sustain them.[14]

The heights of the bridges restricted the diameter of the paddle wheels; the widths of the locks restricted the size of the paddle floats. The Mechanics’ Magazine drawing does not show paddle floats or boxes, so it is not clear how they fitted in when the two parts of the boat were alongside one another; perhaps they were at the forward end of the rear section.

The trials

The Saunders’s report said:

Lengthened and careful experiments have been made with this steam boat, as to speed and management, &c, on the six mile level of the Royal Canal — running measured distances.[15]

This might refer to the 7.5 mile [12.1 km] level[16] from the 12th Lock at Blanchardstown to the 13th at Deey Bridge: it is close to Dublin and to Mallet’s foundry. However, it is not clear where the boat sections could be turned at the Deey end. The response of the crews of horse-drawn boats to the approach, at speed, of a narrow 120 foot [36.6 m] boat is not recorded.

Saunders’s said that the boat was easy to manage, especially in locks: reversing the engines could stop the boat in its own length so check-ropes were not needed. The engines used 114 lb [52 kg] of coke per hour, including that used in getting up steam.

Mallet said that “The boat was tried upon both canals […]”, the Grand as well as the Royal, one 40 feet [12.2 m] and the other 44 feet [13.4 m] wide on the surface, “flat bottom of 25 feet [7.6 m], sides sloping ahout 1½ to 1, and mid-depth 6 feet [1.8 m] to 6½ feet [2.0 m] of water”. It was also tested on “the comparatively open waters of the [River] Liffey, at the port of Dublin, where she attained an estimated speed of about 10 miles an hour” [16.1 km/h]; Saunders’s said that in open water “her speed has been found to reach as high as nine-and-a-half to ten miles per hour” [15.3–16.1 km/h].

On the canals, Saunders’s said that, with crew, ballast and enough coke for the journey, the boat’s speed was “between six and seven British miles per hour” [9.7–11.3 km/h]; it said that, on the Limerick Navigation, partially river and partially canal, the boat’s average speed would be at least 7 mph [11.3 km/h]. Mallet, rather more precise, said:

With a load equivalent to sixty passengers and their baggage, a maximum speed of 7.08 miles an hour [11.4 km/h] was attained, with the original oval float boards, 24 inches [61 cm] deep and 17 inches [43 cm] wide, and with the engines working considerably below their full speed.[17]

According to Mallet, the trials were quite extensive, including different types, sizes and shapes of paddle floats, different radii of paddle arms and different dips. The floats included the feathering oar-shaped floats invented by John Oldham and patented with the assistance of Charles Wye Williams, founder of the CoDSPCo. With conventional floats, a wave went at an angle of 30° “from the tail of each paddle wheel towards the bank” and was reflected several times, “producing a set of waves crossing in a lattice form”. However, the feathering floats produced a surge across the canal, with a continuously breaking wave not far from the stern.

Mallet even tried providing equine assistance:

One curious experiment was made by attaching three picked and powerful fast post horses to the steam-boat, capable of keeping a strong strain upon the tow line while the engines were at work. On one occasion he started the engines and four horses at the same time, when the speed of the boat was rapidly brought up to 10 miles an hour [16.1 km/h], and that rate was maintained for perhaps 300 yards or 400 yards [274–366 m], the engines flying away and the horses being scarcely able to make speed enough to keep the tow lines taut. The true wave of translation was now soon produced, upon which the boat for a short time rode. This increased in magnitude, and very soon brought down the speed of the boat to its own rate, or to 8 miles an hour [12.9 km/h]. Throwing off the horses when the speed was highest, it was almost immediately reduced to about 5 miles an hour [8.0 km/h], and until the water got tranquil could not be restored.[18]

The wave

Saunders’s explained that a moving boat on a canal produces, ahead of itself, a “wave of translation” whose speed is proportional to the depth of the canal. When the boat’s speed is less than or equal to that of the wave, the wave holds the boat back. The amount of retardation is proportional to the size of the wave, which depends, inter alia, “upon the magnitude of the immersed body originating it in relation to that of the canal”.

However, if the boat can be made to exceed the wave’s speed, the wave assists rather than retarding the boat’s progress. “Hence,” Saunders’s said, “the value and peculiarity of fly-boats with which all are now so familiar.”

Furthermore, there was the possibility of damage to the banks. In a rectangular canal, of the same depth across its entire width, the wave would not break, but on real canals, shallow at the edges, the wave breaks continually and damages the banks.

Those factors meant that, on a canal 40–45 feet [12.2—13.7 m] wide and 7 or 8 feet [2.1—2.4 m] deep, a fast boat could not be larger than a contemporary fly-boat. But, as such a boat was already fully laden with crew and passengers, it could not also carry a steam engine. Saunders’s said that previous canal steamers had been twin boats (catamarans) or wide-beam single-hull boats, none of which had ever exceeded 4½ British mph [7.2 km/h] miles per hour despite creating a destructive surge.

Saunders’s reported that Watson’s boat produced “scarcely any wave of translation” at 6 mph [9.7 km/h], with no surge from the paddle-wheels that could injure the banks. Mallet agreed that the boat reached that speed, on either canal, “without notable disturbance”. Above that speed, though, the boat did produce a wave — but it was not a wave of translation and it did not exceed 9 inches [23 cm] high:

A wave was then produced, the crest of which crossed the canal close in front of the boat, which never rode upon it or over it. It was not a wave of translation, for the speed of such a wave, due to the depth […] of these canals, was about 8 miles an hour [12.9 km/h], which the boat never reached.[19]

The boat reached 7 mph [11.3 km/h] with the engines at half power; working up to full power produced more surge along the sides and at the rear but did not cause the boat to move faster. At 32 strokes per minute the boat went better than it did at 55.

At the bridges, where the Canal suddenly narrowed to the width of the locks, or to 14 feet [4.3 m], and where the greatest amount of resistance might have been expected, the engines (for the second or two while the paddles were passing the spot) flew away, showing that the back current of the water, required to fill the comparative void in the wake of the boat, took away the fulcrum from the paddle wheels, and was one of the causes of defective speed.[20]

The outcome

Saunders’s said that if the boat were to travel 24 miles [38.6 km, or 48 km if Saunders’s meant Irish miles] in one day,

[…] and allowing 10 per cent, for interest of capital in boat, complete wear and tear, repairs, wages of crew, &c, the total cost of transit of 60 passengers and luggage, per mile, is ten pence and a fraction, without any injury to the banks, or wear and tear upon the towing paths.[21]

The cost per mile would be lower if the boat worked a full twelve hours a day.

Saunders’s clearly thought the experiments a success and said that, after being fitted out, the boat would shortly proceed to her station on the Shannon by way of the Grand Canal. I have not yet found any record of her entering service there, although I have not exhausted all possible sources.

However if, as Mallet said, the intention was to achieve a speed of 8 mph [12.9 km/h], then the experiments failed. Except on the open water of the Liffey, the boat never achieved more than 7.08 miles an hour [11.4 km/h] under its own steam.

But if it was intended for the Limerick Navigation, and if indeed it never went into service there, that was probably just as well. For its first two [Irish] miles [2½ statute miles, 4 km] above Limerick, the towing-path and the boatstream of the Limerick Navigation are on the south bank, first of a canal and then of the River Shannon. From Plassey, though, the navigation is continued in a stillwater canal whose entrance is on the north bank of the river. Watson’s very long, very narrow boat would have had to cross the river, beam on to the full force of the Shannon, at the foot of the Falls of Doonass.

 

Sources

The issues of the Mechanics’ Magazine referred to here are available online as Google books; “Steam Power on Canals” is available on the Steamers Historical site as a PDF here http://www.steamershistorical.co.uk/steam%20power%20on%20canals.1867.23152.pdf.