THE SECTIONS CLAMPED TOGETHER AS A SINGLE BOAT, OR USED WITH CONNECTING BEAMS AS A DOUBLE.
Full-sized platform boat.
In building a full-sized boat on this model, our plan would be to make the flat side all of ¾in. plank, with the stem, stern post, and keelson all fast in their proper positions, and the keel left slightly apart, so as to allow the sheets of metal, whether iron or copper, to be inserted between it and the keelson. Then, laying the whole flat on its side, we would cross cut with a fine tenon saw our wooden model into eight pieces of equal length, and carefully enlarging the section of each length would make as many temporary frames, and set them upon the flat side, cutting checks in them to let in the stringers, which when bent down to the flat at either end would very effectually give the form of the boat. We would then fit the ribs, keeping them as light as possible with due regard to strength, cutting them, if requisite, out of wood selected with the proper natural curve; or, preferably, using flexible wood, such as ash, in pieces 2in. broad, and ½in. in thickness, and placing them not quite 2ft. apart, so that the overlapping edges of the sheets might coincide with the ribs, and the bolts might pass through them and also through the inner stringers, and the outer ribbands and gunwales at all their points of intersection. The ends of seven of these ribs, at nearly equal distances (as at sheets 2, 5, 8, 10, 13 and 16, on p. 106), we would leave standing six or eight inches above the gunwale, and about four inches from each we would set up another of equal height, so that the cross-beams might lie between them when required, and be secured by lashings passing down to the first stringer ([p. 110]), or so that when the two parts were connected as a single boat they might serve as rowlocks. Short struts from the foremost pair of these would give great additional stability to the masts.
In laying the deck, we should by all means endeavour to avoid injuring the planks by boring needless holes in them, as they might on an emergency be required for building a smaller boat. We should, therefore, lash them with raw hide to the foremost and aftermost crossbeams, and then laying lighter beams across near two or more of the intermediate ones, fasten them down where requisite by strips of the same material ([p. 110]).
For connecting the two sections, so as to form a single boat, we should use screwed bolts ½in. thick, and 7in. long, passing at intervals of about 16in. through both keels, stems, stern posts, and inner gunwales, thus firmly clamping both the flat sides together. The two removable portions of the inner gunwale (marked A) previously mentioned would, in this case, be unshipped to allow the oars free play, as in illustration on opposite page, and on [page 106].
Copper is the only metal we should wish to use or recommend to others, and all fastenings used with it must be of the same metal. We recommend in this case, screwed bolts and nuts, presuming that the boat would be built for a journey, the exigencies of which might oblige the traveller frequently to take her to pieces and rebuild her; but as our own means were at that time inconveniently limited, we made a calculation of the comparative cost of plain and galvanised iron and of wood.
The mode of setting the sails, spreading the awning, &c., will be sufficiently clear from the engraving ([p. 106]).
Our little model, when tried upon the flooded flats at Walvisch Bay, sailed “like the wind,” but had a tendency to bury the lee-bow, which was easily remedied by ballasting the weather quarter; an oar was the readiest and most convenient means of steering.
Estimate of material if the boat be built of copper, the flats or inner sides being of plank:—