1S4I.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL 



105 



NOTES RELATIVE TO TOWING PATHS AND BANKS OF 



CANALS IN GREAT BRITAIN. 



By M. VuiGNER, Inspector of the Paris Canals. 



C Willi an Engraving, Plate II'".) 



(Translated from tlie Frencli.) 



M. VuiGNEK, being commissioned by the company of the Oint'q 

 and St. Denis canals to study the various systems of works in use 

 on the British canals, and particularly to examine the different 

 methods used in forming the foundations of the hauling or towing 

 patlis, and protecting the slopes of the interior banks from the ort'ects 

 produced by the ordinary and irregular fluctuations of the water, he 

 visited, for this purpose, in the course of 1837, the can.ils of that 

 country, which stand the first in construction, and collected consider- 

 able information on the subject. 



In England the canals of Taunton & Bristol, those of Birmingham, 

 (from Liverpool to Leeds) Preston & Lancaster, in Scotland those of 

 Paisley or Ardrossan, the Forth and Clyde, and the Union Canals, fur- 

 nished him with every information that could be required. On his 

 return to France, the company, who wished to establish on the Ourcq 

 canal a set of passage boats, empowered M. Vuigner immediately to 

 apply the information he had acquired. He was first engaged to 

 macadamize the towing path of the left bank of tlie Ourcq canal 

 between LaVillette and Meanx, and caused part of its banks to be im- 

 proved, and he also applied some improvements resulting from his 

 observations in Great ilritain. 



The present paper will contain a description relative to the metal- 

 ling of the towing paths, and the protecting of the Iianks on the English 

 and Scotch canals, as well as describing the macadamizing and facing 

 used on the Ourcq canal to prevent damage by the action of the 

 water. 



Towing or Hauling Paths. 



In England there is generally only one towing path, though, upon 

 some new lines, especially the Birmingham, there aie two paths. This 

 is an exception which a particular circumstance required, but which, 

 however, is not a deviation from the general rule. The Birmingham 

 has a towing path on both sides until it is divided into two branches, 

 one to Wolverhampton, and the other to Walsall, each having their 

 towing paths, one on the right side and the other on the left. On 

 that part where there is a towing path on each bank, the navigation 

 is extremely active, amounting to more than lOOU boats per week. 

 The navigation is facilitated, and at the same time the horses that 

 tow the boats coming from Wolverhampton and Walsall have not to 

 change their sides, nor obstruct one another. The breadth of the 

 towing paths is generally not more than 10 feet, which is considerably 

 less on some canals, and especially at Taunton, a canal of very sraail 

 section, navigated by boats of only 10 tons. 



On the new line of the Birmingham canal, the breadth of the towing 

 path in cuttings is about 12 feet, and on embankments 15 feet. The 

 path is generally divided into three parts, one part next the canal 

 forms a fender or raised mound 1 ft. (i in. to 2 feet wide, which is 

 turfed over, the middle part forms the trackway for the horses, and is 

 covered with metalling or broken stone to the width of five or six feet, 

 and the other part is the remainder of the land unappropriated; 

 sometimes it contains a drain for carrying off the surface water, and is 

 enclosed with a hedge which determines the limit of the canal pro- 

 jjerty. On the opposite bank, there is, in some parts, a footpath 

 about 3 feet wide, but more frequently the underwood or cultivated 

 land reaches to the water's edge, so that no more land is taken than 

 what is absolutely necessary for the canal. 



On the Preston, Lancaster, Paisley, Forth & Clyde, and Union Ca- 

 nals, where there are fast passage-boats, the width reserved for the 

 fender between the towing path and the interior slope of the cuial, is 

 on the average two feet wide at the base, and raised from (! to S inches 

 above the path, or from 2 ft. to 2 ft. G in. above the surface of the 

 water, the top, about 1 ft. to 1 ft. 4 in. wide, is generally turfed over. 

 The interior edge forms the continuation of the interior slope of the 

 canal, and the outer edge is sloped and protected with large round 

 pebbles placed at intervals of 2 to 3 feet, which are partly imbedded 

 in the earth, and project about 2 inches above the fender :' these peb- 

 bles are now abandoned, as they were found inconvenient for the 

 towing ropes when the speed was slackened. On some parts of the 

 canals the fender is formed of flat stones, the edge of which forms the 

 top of the stone facing of the bank, as shown in sections. Figs. 17, IS, 

 and i'.). The fenders answer the purpose for limiting the track of 

 the iiorse, preventing the mud being washed over the path, and a pro- 

 tection to the edge of the slope. 



No. 43.— Vol. JV.-Apkti., IBll. 



The towing path of the above canals is mostly formed of a layer of 

 broken or round pebbles laid to a thickness of 4 to (i inches according 

 to the nature of the soil, and then covered with a layer of gravel from 

 1 in. to li in. thick. On some parts marly clay is used to bind the 

 pebbles, and on other parts, especially at the stopping places, at the 

 bridges, and even the whole length of the Paisley canal, the pebbles 

 are covered with a hiyer of iron slag, which, w'hen well beaten in, 

 forms a path extremely hard and compact, besides, it is not slippery 

 in rainy weather, and is free from dust in sunmier. The broken 

 pebbles used are generally not larger than Ij inch at most. The best 

 macadamized paths are'those made of broken- limestone, and better 

 stiU with basalt ; these materials are found nearly every where on the 

 banks of canals, which renders their formation and repair very cheap. 



The transverse slopes of the towing path, wliere there are fast pas- 

 sage boats, have an inclination of about 2 inches to the yard declining 

 from the canal : this inclination is found to give the best hold for the 

 horses' feet. The surface water is carried off on the outside of the 

 path, and is seldom allowed to run into the canal, excepting in such 

 parts where the canal is formed in cutting; it is then carried off by 

 under drains of dry stones, which pass under the towing path trans- 

 versely from longitudinal gutters or drains, formed on Vvc oatside of 

 the path. 



Towing Paths of L' Ourcq Canal. 



The towing paths of this canal, and in general on all the French 

 canals were formed on the natural soil, without the least metalling or 

 stoning of any sort ; in winter time they were quite impassable in 

 parts, especially in the Paris division, between La Villette and Claye. 

 In this state of things it was difficult to think seriously of establishing 

 passage boats, which the Ourcq and St, Denis canal company was de- 

 sirous of introducing into France ; they therefore determined upon 

 adopting the English system of macadamizing the towing path of the 

 left bank of the Ourcq canal between La Villette and Meaux. On 

 the Ourcq canal the ordinary boats are to.ved up by one horse; but 

 the passage boats, as well as the Government boats, are towed by 

 two horses abreast, as well going up as down, which is still the case. 

 The experiments which were made on the speed of passage boats, 

 showed that three horses, two horses abreast in front and one behind, 

 were necessary for towing these boats. It thus became necessary to 

 increase the width of the towing path. In those places where the 

 banks had retained their first form the breadth of the path was 13 ft,, 

 which was diminished to lift. in., where the banks were raised 



1 ft. 6 in. above the surface of the water. The towing path is now 

 reduced throughout to a breadth of 9 ft. (i in., consisting of a fender 



2 ft. wide at the base, the trackway for the horses Ij ft. G in. wide, and 

 a drain 13 inches wide. In the Meaux division they have only al- 

 lowed a breadth of 6 feet for the towing path, but the drain has been 

 increased to 19 inches wide, which still gives a breadth of near S feet 

 upon which the horses can walk or run with ease. Tliis breadth 

 might be considered insuiBcient at the points of crossing, where four 

 horses have to pass ; but the company decided that in case that should 

 occur, they would cause the front horses to be harnessed one before 

 the other. Another important consideration which determined the 

 company to adhere to 9 ft. G in. was that of economy, as it would 

 involve an extension of the work for more than 30 miles between La 

 Villette and Meaux, and double that distance if extended between La 

 Villette aud Mareuil. 



Experience has proved that the adopted width is sufficient for the 

 different boats, as the horses of the passage boats in general never pass 

 each other, excepting at the difterent stages, where the path is 

 widened. As regards the horses of the other boats whentliey pass, the 

 horses go a little on one side, or on to the exterior slopes, and if it be 

 found too inconvenient to act thus, it is immediately obviated by har- 

 nessing the horses one before the other as before observed. 



The breadth being settled, it then became necessary to fix the l:eight 

 of the towing path above the surface ofthe water. Between La Villette 

 and Meaux the top of the interior slope was 8 ft. above the b;;ttom, 

 but between LaVillette and Claye it was only G ft. G, and from Meaux to 

 Claye .5 feet, so that the same height of path could not be adopted 

 throughout. Between La Villette and Meaux the height of the fender 

 was fixed at 2 ft. G in. above the sufface of the water, aud G inches 

 above the towing path, which made the latter 2 feet above the water, 

 as shown in sections. Figs, a, 7, & 14. 



The paths were formed in some places with broken limestone, in 

 other places with clean pebbles mixed with sand or coarsa gravel, and 

 laid to a thickness of 4 to 5 inches, and covered with a layer of gra- 

 velly sand from 1 in. to Ij in. thick; the pebbles, when mixed with 

 coarse gravel, were used without an extra coat, and l.dd to a thickness 

 of d inches. As soun as the paths were finished, a roller 5 feet broad, 



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