As the strength of ships to resist the impulse of waves and accidents from shot, or from taking the ground, not only depends upon the manner in which they are put together, but also upon the size of the material employed, we shall give a scheme of scant lings for all classes according to the latest improve ments.
The first operation necessary in building a ship is, to place pieces of wood on the slip destined to receive her, about four feet apart, for the reception of the keel: these are called blocks, and are laid at a declivity of t of an inch to every foot of the length to which they extend, or at an angle of 3' 20'. The keel is usually composed of elm logs, sca•phed and bolted to gether. When it is secured on the blocks by treenails, the dead-wood forward and abaft is placed thereon, the form thereof is given by the line shown in the sheer draught called the cutting down line; as a (Plate CCCCXCIX. Fig. tO); the floors are then crossed in the keel, or the half floors put in place, (Plate CCCCXCVIII. Fig. 6,) the stem and stern post are raised, and if the vessel is to be built with a square stern, a frame is got up called the stern frame; this is composed of the stern and inner posts, with horizon tal timbers fastened in their middle to the stern post, called transoms, and timbers which give the form to the sides of the stern called fashion pieces. In ships with circular sterns, the timbers are carried round with the same uniformity as in the sides, in order to give strength and security; (Plate CCCCXCVIII. Fig. 4;) those in the fore and alter bodies of all ships, are canted so as to give the requisite forms. The frame timbers are formed into bends, being composed 1st, 2d, 3d, 4th, and 5th futtocks, and top-timbers, (the number of futtocks varying according to the sizes of the ships and lengths of the timbers,) the first fut tock a butt on the cross pieces, the second on the head of the floor or half floor, as the case may be, the third on the first, and so on throughout the assemblage, care being taken that the timbers be so disposed that the strength of the whole body be lessened as little as possible by the necessity of having them cut off by port holes.
The heads and keels of the timbers of the frame are converted square, so as to form -abutments, and are united with cocks, which are let in two inches into the head of the one timber, and two inches into the heel of the other; when these timbers are properly trimmed, they are bolted together so as to form two bends of timbers in each connected frame. When all the bends are raised and secured in their proper places (so as to give the form of the body,) by shores, rib bands, and cross spauls, the keelson is put in place and bolted, and the ship is then said to be completed in frame, or to apply a term used of an animate to an inanimate body, the skeleton is formed. In this state
the frames of ships of the line remain at least twelve months, in order that the vegetable juices may be evaporated before the planking is commenced: those of frigates and smaller vessels siK mouths: this is tech nically called seasoning.
The frame of a ship is usually converted in its sid ing from to 4 an inch larger than the required di mensions, and the heads of those timbers which re main naked, are generally six or eight inches longer than the given scantlings. These are termed over cast. Before the planking is commenced, the frame is dubbed over with an -adze till wrought to its proper dimensions, and the timbers are reduced to the length required.
The main wales and thick stuff over them are then brought on coaked to the timbers, and fastened also by bolts and treenails, these are worked top and butt, or anchor stock fashion, or with parallel strokes, ac cording to the nature of the materials employed and their economical use; the ship is shored by the main wales, which shores remain until her completion, to prevent any alteration in form.
The °Hop clamps and shelfpieces are then worked, and the beams and half beams placed thereon, these are coaked and bolted thereto, the former are also united to the keels of the chocks under the gun-deck beams by the plates. A solid bottom being a princi pal feature in the new mode of shipbuilding, not only to give strength to the fabric, but also security to the seamen in case of accident_ to the plank of the bottom by striking upon a rock, this operation is carried into effect by filling the smaller interstices between the lower timbers as high as the floor heads with strips of wood, and thence upwards by driving firmly in the openings between the frame timbers, on the outside, pieces of oak three inches thick, until they make a fair surface with the timbers; on this is placed a com position formed of two parts of lime of a particular description, called Parker's cement, and one part of drift sand, the mixture is placed on the outer tilling of wood until it comes within 21 inches of the surface inside; an inner tilling of oak similar in all respects to the outer is then placed on this, and by being dri ven firmly against the cement, forces it into all the interstices, and thus renders the bottom to within three inches of the plank under the orlop clamp, one solid mass. The fillings are then dubbed fair, and slightly caulked on one of their sides and well rammed and caulked on the other.