One of the most important matters that the canal engineer and manager has to deal with, is the adoption of the form of boat best suited for the gauge of his canal and the character of the traffic to be dealt with. The majority of canals are of too limited dimensions to admit of the employment of boats of large size. Even on some of the largest rivers—such as the Thames, the Danube, and the Rhine—the size of vessels employed has to be kept down to a limit which would be deemed ridiculous for ocean-going steamers. This fact alone renders the cost of transport on inland waterways much greater than the cost of sea transport. There is also the great drawback to be met, that on many through lines of communication, as on the through canal routes from Birmingham to London, and from the same midland capital to the Severn, the break of canal gauge renders it necessary to employ the size of boat suited to the minimum gauge, and this is, of course, a great waste of power.

The modified French canals of 6½ feet depth admit barges of 300 tons; and a depth of 8½ feet, on the Canal du Centre, of Belgium, allows of the passage of 400-ton barges. The large traffic on the Erie Canal, between Lake Erie and the Hudson River, is conducted in barges of 250 tons; the canal has a depth of 7 feet, with a bottom width of 56 feet, and pitched side slopes of 1 to 1·5; and the locks are 110 feet long and 18 feet wide. The Welland and St. Lawrence Canals are on a larger scale, as they provide access to the coast for the large inland lakes of North America, with vessels of 1000 to 1500 tons, and therefore, like the Ghent-Terneuzen Canal, occupy a sort of intermediate position between inland and ship canals.

The “river steamer,” as the stern-wheel shallow draught vessels on Canadian waters are called, is a boat of peculiar construction. Three things are absolutely necessary. First, a perfectly smooth bottom; second, an absence of rigidity in the hull and motive-power; third, a propelling-power on the surface of the water—three points, apparently easy of accomplishment, but in reality very difficult, and which to understand requires long practice with the steamers, and their uses. Indeed, no inconsiderable portion of a captain’s or pilot’s life has passed before he has learned the “handling”; but when once the lesson has been learned, it is wonderful what can be done with these wheelbarrow steamers.

Mr. Shelford[303] holds that these are by far the most useful class of boats employed on the canals of Canada. The absence of a keel or any such obstruction enables the boat to be turned like a dish on the water; while the four rudders (sometimes 20 feet long) will guide her with a nicety in rapids and currents where an ordinary steamer would be helpless. The absence of rigidity in the hull and machinery enables the steamer to be driven ashore on any soft bank, the cargo discharged or loaded, and the boat without difficulty backed off.

The propelling power is a large diameter wheel at the stern of the boat, the full width of the vessel, resembling the undershot wheel of a mill, and driven by two cylinders, one on either side. The floats of this wheel are but 8 to 10 inches in the water when light, and 30 inches when loaded, and do not therefore produce those destructive currents which come from the screw or paddle steamer.

The boats which are used on the rivers of the north-west of Canada are about 220 feet, 38 to 40 feet beam, and 10 to 12 inches draught when light, and carry themselves about 400 tons, and will push (not tow) three times as much more on barges built like the steamers.

Perhaps the most efficient system of canal boats and of canal transport generally known in the United Kingdom is that adopted on the Aire and Calder Canal. Steamers are employed to tow a fleet of canal boats or barges, varying from ten to twenty in number, each carrying about 40 nett tons of traffic. The locks, which are 215 feet in length, take the steamer, tender, and eleven boats all at one time; but if there is a longer train of boats, it has to be broken in two. The boats are 20 feet long, 16 feet wide, and 7 feet or 7 feet 6 inches deep. When loaded, they draw from 6 feet to 6 feet 6 inches of water, and the whole train carries from 700 to 900 tons. Usually, instead of towing these boats, they are pushed from behind, which offers an advantage in the steering. The steamer has two direct-acting cylinders—one on each side, and a wire rope is carried round a pulley direct to them, being afterwards threaded through guides attached to each boat. The steering arrangements are so contrived that the train can go to any curve by the two convex surfaces, and yet it is free to rise and fall vertically. The boats are coupled together by wire ropes, which run alongside the whole of the boats through guides at each corner of each boat. The ropes are then passed over the steering wheel upon the steamer. The boats are really iron boxes, which, when traffic is carried, say from Leeds to Goole for shipment, are placed in a hoist, inside which there is a cage with a cradle, in which the boat is secured. When the boat has been raised to the height of the shoot it turns over automatically and discharges the coal or other cargo into the ship through the shoot or spout employed for that purpose. The boat and cradle, having resumed their original position, are then lowered back again to the canal-level by the same hydraulic arrangement employed to raise them. Mr. Bartholomew, the Manager of the Aire and Calder Canal, has stated[304] that the cost of mineral transport by this system, including the return empties, was only 0·0119d. per ton per mile; the cost of tugs carrying general cargo and merchandise being ·034d. per ton per mile; whereas the cost of the same traffic on the Leeds and Liverpool Canal, where similar facilities do not exist, would be ·30d. per ton per mile. The difference of cost is mainly due to the difference in the number of men employed. Usually, two men are employed on each boat, and four men are employed for tugging, making 28 men in all for 12 boats, whereas a train of boats can be worked by the system described by the tug crew of four men only. The Aire and Calder Company have now arranged their boats in such a way that they may carry general merchandise as well as minerals, having fitted them with decks and hatchways for that purpose.

Mr. E. J. Lloyd submitted to the Select Committee on Canals (1889) a statement showing the size of the craft that the various canals of England and Wales were capable of carrying.[305] The figures are instructive, and are worth perusal by any one interested in the subject. It showed that there are very few cases in which the existing navigations can carry craft over 100 feet in length. The most usual dimensions are 70 or 75 feet by 12 or 14 feet width. The Aire and Calder Canal, which takes boats of 212 feet by 22 feet, is a notable exception to the general rule. Boats of 163 feet by 29 feet 6 inches can also travel on the Gloucester and Birmingham Navigation, while the Severn can take craft of 270 feet by 35 feet, and the Thames, from London Bridge, can carry vessels of 140 feet by 22 feet. Again, on part of the Kennett and Avon Canal, craft of 120 feet by 18 feet can be navigated. Mr. Lloyd, who has had a great deal of experience in canal navigation, has proposed the adoption of improved locks on the leading English canals capable of taking boats 110 feet long, 11½ feet wide, and 6 feet draught, the carrying capacity being about 120 tons.[306] Mr. Abernethy has proposed that the canal boats should be capable of carrying 200 tons, and the canals adapted thereto;[307] while Sir James Allport has contended that for facility of handling traffic small boats are better than large ones, and should be preferred accordingly.[308]

In India, steamers have been placed by Government on the Sone canals, and will continue to run until the task is taken up by private enterprise, as is now being done on the Orissa canals.

The following is a description of one of them named the Koel:—

Of which 5¾ tons are used on the trip between the head of the canal and Arrah and back, being a run of 116 miles, occupying about 26 hours, or at the rate of 7·450 lbs. per hour, a very large consumption for an engine of 25 nominal H.P.

Accommodation is provided for 8 first-class passengers and 150 second-class passengers, with a cargo capacity of 2500 cubic feet, or 50 tons of 50 cubic feet.

The engine of 25 H.P. was one of the locomotives used on the Quarry Tramways. The pressure of the steam is 120 lbs. The vessel is built with a single paddle-wheel, 11½ feet diameter, at the stern with 20 floats, 5 feet long by 1 foot broad.

The hull of the boat is ³⁄₁₆ths iron, perfectly flat-bottomed and rectangular in section, with rectangular bilge. The bow is curved, with a vertical stern, and the stern is sloped off for 24 feet to a vertical depth of 1 foot, for the purpose of enabling the backwater to escape when the wheel is reversed. There are two rudders, and the steering is managed from the fore part of the boat. Her speed is between 6·5 and 7 miles an hour in the canal, but the run of 58 miles occupies from 11 to 12 hours down stream, and 13½ to 15 hours up stream, owing to the delay in passing the locks, of which there are six.

These steamers last year carried 42,900 passengers and 2500 tons of goods, earning 3175l.

The cost of working the different steamers, inclusive of all charges but that of interest and depreciation, amounted to from 9·36d. to 36·48d. per mile run.

The total earnings of the canal for the past year was 7080l., against 9300l. in 1881-82.

The tolls levied on boats are from ⅛d. to ¹⁄₅d. per ton per mile.

The charges by the steamer amount to about ⅜d. per ton and per passenger per mile. The charge by native boats varies with the demand, and is high. The bulk of the traffic is carried in native boats, which are worked by men. The sections of the two main canals in the Sone system are very large. They have to provide for the irrigation of 1,295,000 acres. They are about 200 feet broad, with a depth of 9 feet in full supply, diminishing to about 7 at the minimum. The branches vary from 90 to 60 feet at surface, with a minimum depth of 6 feet.

The time occupied by a boat in passing through a lock comprises the entrance and exit of the boat, and the operations in locking. By the adoption of sluices in the side walls the locks on the Bourgogne Canal can be filled or emptied in two minutes; but the time employed in taking in and bringing out a boat varies considerably, depending on the speed of the boat, its draught, and its method of traction. Steamboats, carrying from 100 to 150 tons of merchandise, traverse a lock in from six to eight minutes, whilst yachts and torpedo-boats have passed in four to six minutes. The main water traffic between Paris and Lyons is carried on by new boats 125 feet long, and having a draught of 4½ feet, being limited by deficiency in the depth of the Yonne. These boats can carry 210 tons, but their load is usually between 130 and 180 tons; they perform the journey between Paris and Lyons in 11 to 12 days, traversing the Bourgogne Canal in six or seven days.

Boatbuilders often err in constructing boats of the largest size that the locks will admit, thus rendering the entrance and exit of the boats both slow and troublesome. A boat of 200 tons, travelling 22 miles per day, is more serviceable than a boat of 275 tons which can only go 12½ miles. The greater speed entails a somewhat greater cost in traction; but it admits of more voyages, the transport of more freight, and a more regular service. The lengthening of the locks on the Burgoyne Canal, by enabling the tonnage to be increased by one-third, without diminishing the speed of transit, or notably increasing the cost of traction, has proved a profitable work for the inland-navigation commerce of France.

In 1871, the Legislature of the State of New York, with a view to enabling the Erie and other canals under their jurisdiction to be more profitably utilised, passed an Act to foster and develop the internal commerce of the State, by inviting and rewarding the practicable and profitable introduction, upon the canals, of steam, caloric, electricity, or any motor, other than animal power, for the propulsion of boats.

The first section of this Act appointed a commission to practically “test and examine inventions, or any or all devices, which may be submitted to them for that purpose, by which steam, caloric, electricity, or any other motor than animal power, may be practically and profitably used and applied in the propulsion of boats upon the canals; said examination and tests shall be had by the said commissioners at such time or times during the season of canal navigation, for the year 1871-72, as they may order and direct; said commissioners shall have the right, and they are hereby expressly required, to reject all such inventions or devices, if, in their opinion, none of the said inventions or devices shall fully and satisfactorily meet the requirements of this Act; but said commissioners shall demand and require,

On the running canals of China, Sir George Stainton observed a boat of light construction, with only 14 tons lading, of 8 feet width of floor, about 10 feet width of water-line, and 50 feet of extreme length, drawing 2 feet 3 inches of water, and sharp at the ends, dragged against a stream whose velocity was 5½ English miles per hour; and, although there were twenty-eight trackers, or men hauling at the line, fastened to the boat, besides three men in the boat, poling it on, it advanced only at the rate of a quarter of a mile an hour, notwithstanding that the channel was not materially contracted, in either width or depth of waterway, in proportion to the section of the boat.

Many suggestions have been made, and not a few experiments carried out, with a view to enabling canal boats to navigate waters covered with ice—the use of canals in cold countries being usually limited, from this cause, to about one-half of the year only. None of them appear, however, to have been very successful.

About the year 1796, the Chevalier Bentancourt Molina presented to the Society of Arts a model of a barge, having a windlass in its stern, which gave a circular motion to a pair of knives or scythes, or a lever giving an alternating motion to knives, for mowing off weeds close to the bottom of a canal in which the barge is to float, or on the sloping sides of the canal; for which purpose the knives could be made to revolve at any depth below the surface of the water, and either horizontally or inclined at any angle. In most winters it happens that an ice not more than 1 or 1½ inches thick continues for a considerable length of time on canals and other stagnant waters. This, or even a less thickness of ice, is sufficient to stop the trade upon the canals unless the ice is broken; and for this purpose it is advisable, every morning of a frost, unless the ice should be found more than usually thick, and the frost increasing and likely to continue, to break the ice. This was in some cases done by a strong and square-headed barge, whose sloping or projecting head was covered with strong iron plates. One of these barges, being drawn along the canal and into each lock by several horses, has a tendency to rise upon the ice, and thereby breaks it down before the boat. About the lock-gates it was necessary to break the ice by stamping with the end of a pole. Mr. Symington provided the head of his steam-barge with stampers, to be worked by the engine, for breaking the ice before it in frosty weather.

The tempting prospects of towing a train of ten 100-ton barges with scarcely any more power than would be required to tow only one of them, and the alluring advantages of speedily loading each separate barge, and of detaching and attaching barges at intermediate wharves along the canal’s course, were held out in a proposal recently discussed in France for adopting single-width canals.

On the other hand, however, it has been argued that in this case a regular time-table would have to be strictly enforced; all boats would have to be made up into trains, involving loss of time at starting; there would be delays at the turn-outs, where the canal was widened for allowing the return trains to pass; and steamers could no longer go where and when they pleased. Bridges and locks, being already of single width, could be built no cheaper; while the proposed long locks, of 150 metres = 490 feet length, to take a train of barges, would cost much more than the present French locks of 126 feet length. Even with very few locks, a single-width canal would not come more than one-ninth cheaper than the ordinary canals of double width. At the outside, therefore, it would not take off more than 1 millime per tonne-kilom. = 0·016d. per ton per mile from the tolls. Under the head of towing, the only possible saving would be in consumption of coal in the steam-tugs, which on the Willebroeck Canal costs about ¼ millime per tonne-kilom. = ·008d. per ton per mile; if half this were saved in a single-width canal, ¼ millime = 0·004d., would be all the economy thereby effected. As for dispensing with barges on all except the tug and the rear barge of a train, it has been argued that it would be practically impossible to work a train of rudderless barges round the bends of a canal, and it would be a most tedious and difficult job to handle the barges separately at the wharves and docks where the train has to be made up or dispersed; moreover, the cargoes would not get properly watched, with so few men to look after them. The total saving possible on a single-width canal, 0·020d. per ton per mile, would be likely to be swallowed up by the extra management expenses consequent upon having to organise the canal service on a similar plan to that of railways.