The decline of Canadian sailing craft was swifter than its rise; and with the sailing craft went the Canadian-built steamers, because wood was the material used for both, and the use of iron and steel in the yards of the British Isles soon drove the wooden hulls from the greater highways of the sea. Once the palmy days of the third quarter of the century were over the decline went on at an ever-increasing rate. In 1875 Canada built nearly 500 vessels, and, if small craft are included, the tonnage must have nearly reached 200,000. In 1900 she built 29 vessels, of 7751 tons—steam, steel, wood, and sail. Shipowning does not show such a dramatic contrast, but the decline has been very marked. Within twenty-two years, from 1878 to 1900, the Canadian registered tonnage was almost exactly halved. The drop was from a grand total, sail and steam together, of a million and a third, which then made Canada the fourth shipowning country in the world and put her ahead of many nations with more than ten times her population.
CHAPTER VI
SAILING CRAFT: THE BUILDING OF THE SHIP
Shipbuilding was and is a very complex industry. But only the actual construction can be noticed here, and that only in the briefest general way. The elaborate methods of European naval yards were not in vogue anywhere in Canada, not even in Quebec, much less in Nova Scotia. It was not uncommon for a Bluenose crew to make everything themselves, especially in the smaller kinds of vessels. They would cut the trees, draft the plan, build the ship and sail her: being thus lumbermen, architects, builders, and seamen all in one. The first step in building is to lay the blocks on which the keel itself is laid. These blocks are short, thick timbers, arranged in graduated piles, so that they form an inclined plane of over one in twenty, from which the completed hull can slide slowly into the water, stern first. Then comes the laying of the keel, that part which is to the whole vessel what the backbone is to a man. A false keel is added to the bottom of this in order to increase its depth and consequent grip. This prevents the side drift which is called making leeway. The false keel is only fastened to the keel itself from underneath, because such a fastening is strong enough to resist water pressure and weak enough to allow of detachment in case of grounding. The slight projection of the keel itself then gives too little purchase for a dangerous amount of leverage on the frame. A long keel is made up of several pieces of square timber, with their ends shaped into scarfs, an overlapping and interlocking arrangement of great strength. The foremost keel piece is scarfed into the stem, which is the fore-end of the vessel's bow. The aftermost keel piece joins the stern-post, on which the rudder hangs. Elm makes a good keel, especially with oak for stem and stern-post.
The frame, to pursue our simile, is to the ship what ribs are to our bodies. In the same way the planking is the skin. The frame, or ribs, determines the vessel's form. There were, and still are, many varieties of frame. In a very small vessel there are very few timbers. The keel is probably all in one piece, and the planks may possibly run from stem to stern without a break. In this case the unity of each piece supplies enough longitudinal resistance to strains. But when a vessel is large, and more especially when she is long, the strains known as hogging and sagging are apt to rack her timbers apart.
A ship is not built for mere passive resistance, like a house, or even for resistance only to pressures and vibrations, like a bridge. She is built to resist every imaginable strain of pitching and rolling, and so requires architectural skill of a far higher kind than is required (in the constructional, not the aesthetic, sense) for any structure on the land. When a ship is on the top of a single wave she tends to hog, because there is much less support for her ends than for her centre, and so her ends dip down, racking her upper and compressing her lower parts amidships. When the seas are shorter she often has her ends much more waterborne than her centre, and this in spite of the fact that the extreme ends are not naturally waterborne themselves. Then she sags, and the strains of racking and compressing are reversed, because her centre tends to sink and her ends to rise. Now, a series of hogging and sagging strains alternately compresses and opens every resisting join in every timber, with the inevitable result of loosening the whole. To meet these strains longitudinal strength must be supplied. The keel supplies much of it, so does the planking (or skin) to a lesser degree; but not enough; and the ribs, by themselves, are for transverse stiffening only. Four means are therefore employed to hold the parts together lengthwise—keelsons, shelf-pieces, fillings, and some form of truss.
The keelson is an inverted keel inside the vessel. The floors, which are the timbers uniting the two sides of the frame (or ribs), are given a middle seating on the keel. The keelson is then placed over them, exactly in line with the keel, when bolts as long as the thickness of all three are used to unite the whole in one solid backbone, and this backbone with the ribs. Side or 'sister' keelsons were used in the Navy on either side of the mainmast for a distance equal to about a third of the length of the keelson. But they were little used in merchant vessels, and their longitudinal resistance was only partial and incidental. Shelf-pieces and waterways were adapted from French models by Sir Robert Seppings, who became chief constructor to the Navy some years after Trafalgar. They are thick timbers running continuously under and over the junctions of the deck beams with the ship's sides, to both of which they are securely fastened.
The keelson was an old invention and shelf-pieces and waterways were soon in vogue. But fillings and trusses, both expensive improvements, were not much favoured in any mercantile marine. The truss is even older than the keelson, having been used by the ancient Egyptians at least thirty-five centuries ago, and probably earlier. Four to eight pillars rose in crutches from the bottom amidships to about six feet above the gunwale. The Egyptians ran a rope over the crutches and round the mast, and then used its ends to brace up the stem and stern. The moderns discarded the rope, took the strains on connecting timbers, and modified the truss, sometimes out of recognition. But many Canadian and American river steamers of the twentieth century A.D. employ the same principle for the same object as the Egyptians of the seventeenth century B.C. Fillings came from the French, like shelf-pieces and waterways. Seppings put them between the ribs, in the form of thick timbers. The whole frame thus became almost solid against any tendency of the ribs to close together, and quite strong enough against their other tendency to draw apart.