50 NAVAL SCIENCES. 



were once often used during an engagement for the discharge of small arms, 

 but this practice is now generally discontinued. 



The cap, P {pi. 11, Jigs, 1, See, 6^), is a strong thick block of wood, 

 connected with the top of the mast by a square tenon, c {fig. 4) ; the for- 

 ward end has a round hole, through which passes the foot of the topmast, 6/ 

 {pi II, fig. 5, and e,fig. 6). 



The main-top-mast is the first prolongation of the main-mast, and is one and 

 a half times the breadth of the ship in length (81 feet 8 inches). Its thickness 

 follows the proportion of the mast. This mast is secured partly by the cap, 

 and partly by the trestle-trees and fid, a block of wood placed through a 

 hole in the heel, and resting on the trestle-trees, which prevents the mast 

 from sliding down. At the heel of the top-mast is the top-block, through 

 which the top-rope is rove in raising or lowering the mast. 



The main-top-mast cross-trees, Q {fig. 1), form a light frame of four 

 pieces of timber placed across the head of the top-mast, but without any 

 top. Everything above these cross-trees is called top-gallant and royal. 



The main-top-gallant-mast is the second prolongation of the main-mast, 

 arranged in the same manner as the main-top-mast, and measuring three 

 fifths of its length (48 feet). Ships of war usually carry top-gallant-masts 

 of different lengths, which can be changed according to the weather. To 

 the shorter one only one top-gallant-sail is attached ; but the longer one, 

 which is nearly as long as the top-mast, bears two sails, one over the other, 

 the top-gallant-sail, g, and the royal, ^*. 



The main-truck, R {fig. 1), is a circular piece of wood on the head of the 

 top-gallant-mast, fitted with a sheave, to draw up flags and signals. The 

 general term head is applied to the upper end of the masts and top-masts, 

 reaching from the trestle-trees to the cap, and from the joining of the top- 

 gallant-mast to the truck. The entire mast, with the long top-gallant-mast, 

 is 248 feet in length. 



The main-yard {fig. Sdd). The term yard is applied to the spars which 

 are hung across the masts with rigging, and to which the sails are attached. 

 The length of the main-yard is twice and one-quarter the ship's breadth 

 (122 feet 4 inches) ; the thickness is 2J inches for every ten feet in length ; 

 the diameter in this case, therefore, is 2 feet three inches, decreasing about 

 one third at both ends, dd. 



The main-top -sail-yard is /^ of the main-yard (85 feet 7 inches) ; the 

 main-top-gallant-yard is f of the ship's breadth (43 feet 6 inches) ; and the 

 main-royal-yard \ of the ship's breadth (27 feet 2 inches). 



The fore-mast, G {pi. 9, fig. 27), stands at about one tenth of the ship's 

 length aft of the stem (20 feet 6 inches) ; its length is nine tenths of the 

 main-mast (118 feet 10 inches) ; the thickness is in the same proportion to 

 the length as in the main-mast. In the top and the other arrangements 

 the same system is employed, all the parts being designated by the term/o;^, 

 as fore-top, fore-sail, &c. The fore-top-mast is one tenth shorter than the 

 main-top-mast (72 feet long, and 1 foot 10 inches thick). The fore-top- 

 gallant-mast, the second prolongation of the fore- mast, is five sevenths of 

 the ship's breadth (39 feet). The fore-yard is double the ship's breadth 

 V02 



