The Third And Final Commercial Canal

Immediately following the Act of Confederation in 1867, the Federal Government decided to institute a new program for the improvement of the canals. The object was to provide a continuous system from the Sea to Lake Superior with locks 270 ft by 45 ft with a 14 ft draft. This involved major reconstruction of the Lachine Canal, especially at the lower end, where new locks were built alongside the old. The old locks were later enlarged to the new dimensions so that a double channel with a draft of 17 ft on one side and 15 ft on the other was obtained. These led to a basin equipped with a large number of wharves clear of the navigation channel and close to the city of Montreal. As in the earlier developments the intention was to provide a deep channel for seagoing ships, one of which may be seen in Fig. 4. The schooner on the left was discharging a cargo of West Indian sugar at the refinery on the canal. The whole construction project was completed in 1884 at a cost of $6,500,000. Improvements were carried on after this date and have continued up to the present day.

The connecting links between the lakes were also being constructed at this time, the Third Welland canal, with 270-ft locks, being completed in 1884 and the Sault Ste. Marie Canadian lock in 1895 (5).

Work on the Cornwall-Williamsburg canals, overcoming what is now generally known as the International Rapids section of the river, was commenced in 1876. The 200-ft locks of the old canals were enlarged and deepened in stages, the canals being opened for traffic in 1901 although some work was not completed until 1913.

Fig. 7 Diagram Illustrating Development of the St. Lawrence Canals Systems

The Cascades-Coteau section again proved difficult and, as in the improvements of 1841, many surveys were made of this portion of the river before it was finally decided to abandon the Beauharnois Canal and build a new canal on the north shore. The main reason was that even 9 ft draft had been difficult to obtain in the Beauharnois Canal and to obtain a draft of 14 ft it was necessary to have the canal entrance farther west which was possible only on the north side. The new canal, the Soulanges, is shown on the map, Fig. 2 and was commenced in 1892 and completed in 1899.

The gradual development, Fig. 7, of the St. Lawrence River canals system as we know it today was therefore completed by 1901, 200 years after the Sulpician Fathers made the first attempt to defeat the rapids.

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This paper was presented at a meeting of the Society of Naval Architects and Marine Engineers and is reproduced with permission.