The Cingalese catamaran is a log of wood rounded beneath, and scooped out, with two planks lashed on the top, so as to increase the height above water. It has a boat-shaped outrigger, supported on two curved poles, to enable it to carry the large lug-sail, which in a fresh breeze so heels it over that the crew have to sit well out to windward on the connecting-bars to balance the swift but crazy craft. In the Mauritius the catamaran is an ordinary boat with a smaller boat at the end of the outrigger, in which is set a peculiar mizzen. In the Fijis the catamaran becomes a double canoe, with both hulls exactly the same, and bearing a platform giving just a little play, so as to allow of the individual peculiarities of the boats being sufficiently humoured.

These boats, although they may in a few rare cases upset end on—that is, turn a somersault—are the safest craft in the world, for, consisting as they do of double hulls sustaining a raft, should anything go wrong with the hulls, the raft will never sink, but will simply settle down until it floats on the waves. Owing to the great breadth there can be no question of ‘initial stability,’ and an ordinary capsize is impossible, while the very light draught of the hulls will take the craft over places where even a rowing-boat would meet her doom.

To build such a craft is not difficult, and Mr. W. L. Alden has recently shown us how it can be well and cheaply done. Adopting the principle of the flying proa of the Ladrones, which are credited with their twenty knots on a beam wind, he makes his hulls quite flat on one side, and thus avoids the ‘funnel difficulty,’ as it was called in the case of the Castilia and other steam catamarans, where the inner sides of the hulls being curved, the water between them was heaped up as it rushed through the narrowing strait. To make such a catamaran as that shown in our [sketch]—a craft speedy, safe, and handy, which is easily built, and will bear any amount of rough usage—four deal planks are required. These should be fifteen feet long, eighteen inches wide, and an inch thick. The width is unusually great, but should single boards not be obtainable, two or three boards can be keyed together so as to make it up. Take one of the planks, which should have been bought ready planed, divide it into five equal parts as shown in the diagram, and at each of the four divisions screw, with brass screws, a three-inch batten three-quarters of an inch thick. This will not only prevent the plank from warping, but will strengthen the joints if you are working with a board that has been made up.

Fig. 1-6.—Construction of Catamaran.

[Fig. 1-6 enlarged] (146 kB)

Now shape the ends as shown in [Fig. 1], first with a saw and then with a draw-knife and spokeshave. Take another of your eighteen-inch planks and treat it in exactly the same manner, and when you have finished the curves, which should exactly resemble the others, cut off along the longer side an inch and three-quarters off every cross-piece, so that when the planks are placed at right angles together they will fit close. Whitelead these edges thoroughly, and then nail the planks together with galvanised iron nails, as shown in [Fig. 2], which gives you a section end-on. Now cut four quadrants eighteen and a quarter inches radius, and off one side cut a strip an inch wide and trim the other end so as to leave you a piece of the shape shown in [Fig. 3], one side of which (A B) is seventeen inches long, and the other (A C), eighteen inches, and which is so made to fit exactly into the angle made by the broad plank and close against the battens as sketched in [Fig. 4]. Finish all the edges off smooth and square and true, whitelead them well, and fix them in with galvanised iron nails.

Now make, or get made, six iron staples such as are shown in [Fig. 5], where the distance from A to B horizontally and A to C vertically is just four inches. The iron is best an inch and a half wide, between an eighth and a quarter of an inch thick, and in it should be three holes, shown at P and in the ears marked H, large enough for quarter-inch bolts. You also require six other staples of the shape shown in [Fig. 6], made of half-inch rod iron with counter-sunk sockets for the screws, and these, like the eared sockets, must be four inches wide.

Figs. 7 and 8.