THE SEAMAN'S MANUAL. PART I CHAPTER I. GENERAL RULES AND OBSERVATIONS. Construction of vessels. Tonnage and carriage of merchant vessels. Proportions of the spars. Placing the masts. Size of anchors and cables. Lead-lines. Log-line. Ballast and lading. CONSTRUCTION OF VESSELS.-As merchant vessels of the larger class are now built in the United States, the extreme length of deck, from the after part of the stern-post to the fore part of the stem, is from four and a half to four and three-fourths that of the beam, at its widest part. The Damascus, of 700 tons' measurement, built at Boston in 1839, and considered a fair specimen of our best freighting vessels, had 150 feet from stem to stern-post, and 32 feet 6 inches extreme breadth. The Rajah, of 530 tons, built at Boston in 1837, had 140 feet length, and 30 feet beam ;— being each in length about four and six-tenths their beam. A great contrast to this proportion is exhibited in the most recent statistics (1841) of vessels of the same tonnage in the English navy; as the following table will show: These may, perhaps, be considered the extremes of shipbuilding; and between these there is every grade of difference. TONNAGE AND CARRIAGE OF MERCHANT VESSELS.-The amount a vessel will carry in proportion to her tonnage depends upon whether, and to what extent, she is full or sharp-built. A sharp-built vessel of 300 tons' measurement, will carry just about her tonnage of measurement goods. A sharp-built vessel of 200 tons or under would probably carry less than her measurement; if over 400 tons, she would increase gradually to fifty per cent. above her measurement. A sharp-built vessel of 600 tons is generally rated at 900 tons carriage. A full-built vessel of 300 tons, after the latest model of American freighting vessels, will carry 525 tons, or seventy-five per cent. above her measurement; and one of 500 tons would carry full double her measurement. The following table may give a pretty fair average:— TONS OF MEASUREMENT GOODS. PROPORTIONS OF SPARS.-There is no particular rule for sparring merchant vessels; some being light and others heavy sparred; and some having long topmasts and short lower masts, and others the reverse. The prevailing custom now is, to spar them lightly, the main-yard being a little less than double the beam; and the others proportioned by the main. Most merchant vessels now have the yards at the fore and main of the same size, for convenience in shifting sails; so that the same topsail may be bent on either yard. The following table, taken from the "Seaman's Manual," will show the average proportions of the spars of merchant vessels of the largest class, as formerly built :- Main-mast, two and a half times the ship's beam. Mizen-mast, five-sixths of the main-mast Topgallant-masts, one-half the length of their top-masts. Main-yard, twice the beam. Fore-yard, seven-eighths of the main-yard. Foretopsail-yard, two-thirds of the fore-yard. For the thickness of the spars, the same book allows for the lower masts one inch and a quarter diameter at the partners, for every three feet of length; and nine-tenths in the middle, and two-thirds under the hounds, for every inch at the partners. For the yards, one inch at the slings, and half an inch at the yard-arms, within the squares, for every four feet of the length. For the breadth of the maintop, one-half of the beam, and of the foretop, eight-ninths of the maintop. The following are the proportions of the spars of the ship Damascus, before-mentioned, built in 1839 : |