whole of the St. Lawrence route; that the locks be made 270 feet long
and 45 feet wide, with a depth of 12 feet clear on the mitre sills;
and that the bottom of the canals be sunk at least 1 foot below the
mitre sills of the locks, with a width throughout of not less than 100
feet. They stated that these dimensions would enable vessels of the
usual build, carrying 1000 tons, to pass, and if their breadth of beam
and sectional areas were increased, the canals might be navigable for
vessels of 1500 tons.
In giving their reasons for fixing the greatest depth of water on this
route at 12 feet, the Commission says:—
“While some of the writers who ought to be best informed on the subject
recommend a draught of 14 feet, and others as much as 16 feet, regard
must, nevertheless, be had to the capabilities of the harbours, and to
the engineering characteristics of our canals, as well as the prudent
suggestions of moderate and experienced men, who have limited their
views to 12 feet. It would be extremely unwise to embark in magnificent
schemes exceeding the resources of a young country, with the view of
introducing ocean vessels into our canals and lakes.”