“Yours very truly,
“Charles Bell.”
Just before returning from South Africa we found that the clever author of “A Painter’s Camp in the Highlands” had also gone through nearly the same course of experiments, and had arrived, like us, at the conclusion that the double form of boat was the most safe, convenient, portable, and roomy on deck; and also that it was objectionable to have the inner sides rounded, for the reasons before given. He therefore finally adopted the flat inner side, and making his boats 30ft. in length and 4ft. apart at the stem, increased the width to 4ft. 1in. aft, so as to let the inclosed body of water glide away more easily. He found, however, that after working out his own idea for his own use, he was served with a notice for infringing a patent of which he had not previously heard; and in like manner, after our return from Africa, a description of a patent tubular life raft was submitted to Captain George, at the Royal Geographical Society, and he immediately saw that this was nearly identical with our own plan.
Making inflatable boats safe.
About 1853, a friend in Graham’s Town, with whom we left our model of the inflatable boat, subsequently used in Australia (see [p. 48]), made one for his own amusement, on a small river. He had but two tubes, each of them with a flat side toward the centre, with a small platform between raised on crossed struts, one pair of which on each side were very ingeniously made to carry the rowlocks, as in the next sketch (Fig. 9). And, as he was doubtful of keeping the canvas of his boats sufficiently air-tight, he either filled them, or proposed to do so, with the bladders of oxen previously inflated, so that, even were air to escape from the tubes which formed the boats, they could not collapse. This, in itself, would be a hint which a traveller, who must either shoot game or kill domestic animals for his followers, would do well to bear in mind.
Skiff of iron or copper.
Iron, whether plain or galvanised, is sold in sheets of 2ft. by 6ft., while those of copper are 2ft. by 4ft. We recommend only the copper; but economic or other reasons may very possibly compel the traveller to use iron.
We have, for facility of construction, chosen the form of a Norwegian praam, or wherry, with both ends alike. A semicircular section slightly flattened at the bottom, without a keel, and rising with an easy sheer to a sharp point at either end.
Eleven sheets of iron would be required; the central one being left of its original shape and size, while the five at either end are cut to the forms shown by the outer lines, and to the dimensions indicated by the figures marked along the lower edge: thus, in No. 1, from the centre there is no perceptible curve along the 6-foot side, but the ends are sloped off, with straight although diagonal lines, so that the side nearest the centre remains 6ft., while the farthest is reduced to 5ft. 9in.
In the next sheet, or No. 2, the side nearest the centre curves very slightly; the segment taking off only one inch at either end, the curved side (supposing we are now working from the centre forward) overlaps the edge of No. 1 two inches, and it is therefore cut, not to 5ft. 9in., but to 5ft. 10in., as No. 1 would be of that breadth, a couple of inches back; the front side is left straight, but is reduced in breadth to 5ft. 5in., and the after side of No. 3 is so much more curved that the segment cuts off three inches. The figures in the diagram will render the progressive diminution to the end sufficiently plain. It will be seen that the end remains one foot wide; this is usually filled in with a semicircular piece of plank, being quite sharp enough for all practical purposes, and affording room for a rowlock for a steering or sculling oar, or for a hole through which the boat’s painter may be passed. But, if desired, another piece of iron, which may be called sheet No. 6, may very easily be let in to continue the curve quite up to a point, as in the dotted end of Fig. 2. The half section is given on the side marked iron of Fig. 3, the outer line standing for the two edges of the central sheet, where the skiff is 4ft. wide and 1ft. 10in. deep. The next line, 1½in. smaller all round, is the section at the overlap of sheets Nos. 1 and 2; the third line, two inches within the last, is at the edges of Nos. 2 and 3; the fourth, three inches smaller, is at the contact of Nos. 3 and 4; the fifth, six inches less, is at Nos. 4 and 5; and the sixth, diminishing by nine inches, is the end of No. 5, which is filled in by a semicircle of plank about five inches in diameter.