The Beams (Plates 6 and 9)

171. The beams are horizontal timbers extending across the ship, for uniting the two sides and for supporting the different batteries, called decks and other platforms. These timbers rested formerly at each end upon the clamps, but now rest on the self, and in the middle upon pillars; they are disposed on the principal decks in general, one under each port and one between, excepting in the places of the hatchways, masts and mizen step, where this order is not exactly observed, but deviated from as little as possible, that they may give the best support to the guns.†

172. Abaft the mizzen-mast, the beams of the middle deck in three-decked ships, and upper deck in ships of other classes, are placed at equal distances and nearer together; as they cannot have pillars under them on account of the tiller. The beams likewise of the round-house, quarter deck, and in three-decked ships the upper deck, are placed in a similar manner, to preserve uniformity, and to present no obstruction to the accommodation, by having pillars under them in the officers' apartments.

173. The beams (plate 9. fig. 21) are distinguished into single-pieces, two (b), three (c), and sometimes four-piece beams (f): the length of the beams and the timbers that can be provided to make them will determined the number of pieces they are to be composed of, which should always be as few as possible; for the quantity of timber required to make them will be increased with the number of pieces, because the number of scarphs is increased.††

174. When a beam is made or composed of more than one piece, the pieces are united together with vertical scarphs. If in two pieces (b) the scarphs is one-third, if in three pieces (c) one-fourth, and when in four pieces (f and g) one-fifth the length of the beam.

175. The scarphs are distinguished into right and left hand scarphs, and are named by the hand that is on the side of the angle, or the side from which the wood to form the scarph is taken off; when at the side end, the face is towards the scarph and looking upon the upper surface; they were formerly bolted with from seven to nine bolts; so as to make their distances apart from 16 to 18 inches, placed alternately, about 2½ to 3½ inches from the upper and lower part of the beams. An equal number of them was driven each lip side and clenched upon the opposite; in addition to these bolts, one nail was driven into each lip on the opposite edge to the nearest bolt, and one bolt, as is always the case now, was frequently driven up and down in each lip to prevent its splitting.

176. The lips of the scarphs were in thickness, to beams from 7 to 9 inches sided, 2½ inches; from 9 to 12, 3 inches; from 12 to 14, 3½ inches; and from 14 inches sided upwards, 4 inches thick. The lips of fir beams were one-quarter of an inch thicker. The breast-beam of the quarter deck and forecastle, if in two pieces, had the lips of the scarphs let in flush, and the beams were sided the thickness of the lip more than the common siding; but if a three-piece beam, the side of the beam that had the lips flush, was placed towards the waist, and if the two end pieces were short of each other, a piece was let in the thickness of the lips between them, so as to make the side of the beam fair.

177. When the beams form the side of the hatchways or ladderways, if a two-piece beam, the lip is made to go beyond the hatchway; but if a three-piece beam, they are placed so that the fair side of the beam may be to the hatchway.

178. In each scarph there were as many circular coaks, within one, as bolts, placed upon alternate edges, about the same distance from the edge as the bolts: they were spaced between the bolts.

179. The scarphs of beams made on the present plan (plate 6, fig. 20) have flush lips, and hook and butt scarphs: the scarphs are set up with iron inch keys (a), which are cut so as to give them about one-tenth of an inch round, in the depth of the beam. The hook butt has a strip of copper (b) on the end grain, to allow the iron key to pass through without injury to the wood: the iron keys are about half an inch short of the depth of the beam to admit of being punched up three-quarters of an inch at the head, and one-eighth of an inch at the point.

The lips of the scarphs should be cut square from the side of the beam; and the up and down way square from the under side of the beam.

TABLE OF THE PROPORTIONATE DIMENSIONS OF THE SCARPHS, BOLTS, &C.
Length
of the
Scarph 		Bolts in the
middle of
Scarph 		Bolts in the
lip of the
Scarph 		Tie-bolts
in each lip 		Treenails
in each
Scarph 		Lips of
Scarph
thick
feet No. Diam.
ins. 		No. Diam.
ins. 		No. Diam.
ins. 		No. Diam.
ins. 		ins.
Gun deck and orlop deck beams 8 2 1¼ 2 7/8 1 5/8 4 1½ 3 1/8
Middle deck beams 7 to 8 2 1 1/8 2 7/8 1 5/8 4 1 3/8 2 7/8
Upper deck beams 7 to 8 2 1 2 ¾ 1 ½ 4 1 ¼ 2 5/8
Quarter deck and forecastle beams 6½ to 7 2 7/8 2 5/8 1 ½ 4 1 1/8 2 3/8

The beams of smaller ships of similar dimensions to any of the above are regulated by this Table.

Footnotes:

† The introduction of half beams generally, which give the flat of the deck a greater degree of firmness against the recoil and percussion of the gun when firing fast, makes it of less importance that the beams should be under the trucks. Back.

†† The quantity will be increased in about the following proportion. If a single-piece be 1, a two-piece will be 1.16, a three-piece 1.25, and a four-piece beam 1.3; but the increased expense will not be so great as these proportions, because timber increases in value in a greater proportion than its dimensions. Back.

John Fincham: Outline of Ship-Building in Four Parts.
Whittaker and Co., London, 1852. Part II, pp 43-45.

Transcribed by Lars Bruzelius

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