70 NAVAL SCIENCES. 



A. Ships of War. 



The length of a ship of war is determined by taking the number of guns 

 in the lower battery, adding the length of their port-holes (2 feet 11 inches 

 for each 36-pounder) and the number of spaces between (7 feet 8 inches for 

 36-pounders), allowing two and a half of these spaces for the stern and 

 prow, and we have the whole length of the ship from stem to stern. A ship 

 carrying sixteen 32-pounders in each battery must consequently be about 

 187 feet in length. Although the spaces between the port-holes are some- 

 times less, the length of such a ship never falls short of 182 feet. 



For the breadth of a ship (that is, the length of its main beam), some take 

 the mean between a third and a fourth of its length, in this case 50 to 54 

 feet ; others take 3 inches 3 lines to every foot of length, making the breadth 

 from 48 feet 5 inches to 50 feet 6 inches. 



The hold (the depth of the ship) goes from the lower side of the main 

 beam to the upper part of the keel ; it is larger at the stern than at the stem. 

 In ships of war of forty-six or more guns, the depth of the hold is equal to 

 half the breadth of the ship, and in frigates is somewhat greater. 



For the angle of the stem-piece we take the eighth part of the ship's length, 

 and for that of the stern post 3^ of the same dimension ; that is, 22f to 20j, 

 and 5 J to 6 feet. This determines the length of the keel. Ship-builders 

 are not fully agreed on this point, however, some preferring to make the 

 stem-piece almost perpendicular, and the stern-post wholly perpendicular. 

 For the height of the stem-piece, some builders take one quarter of the 

 ship's length, others from one tenth to one twelfth, the stern-post being 

 about one fortieth shorter. 



The length of the main transom is two thirds of the ship's breadth ; it is 

 placed at a height equal to the depth of hold and the elevation of the lower 

 deck. No exact rules can be given for the form and position of the ship's 

 timbers. Vessels of a sharp build, in which the timbers make a large spring 

 from the keel before bulging, draw more water than flat-built vessels, and 

 hence present more resistance and make less lee-way. The latter, on the 

 contrary, have less draught and are broader in the hold, which is an advan- 

 tage in laying the lower gun-deck. The position of the main or middle 

 timber, which determines the greatest breadth of the ship, is a controverted 

 point among ship-builders, some placing it further forwards, and others near 

 to the midships ; the last is preferable, as it diminishes the burden towards 

 the stern. The timbers at the stem and stern are drawn nearer to each 

 other, contracting the hold in those parts of the ship : this is done at the 

 stem in order that the ship may cut the water with more facility, and at 

 the stern for the advantage of steering. The timbers are also somewhat 

 contracted at the upper ends (forming the bulge of the ship's sides) in order 

 to break the force of the water and to bring the greatest burden below, to 

 say nothing of other advantages. The breadth and the curve of the stern 

 are according to the taste of the builder. 



Ships of war are divided according to their size into classes, of which 

 there are properly only three, the smaller vessels being called frigates, 

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