The Seaman's Friend

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.

Tons. Deck. Beam. Proportion.

{ Dido 734 120 ft. 37 ft. 6 in. 3.20

English Navy. { Pilot 492 105 33 6 3.13

{ Alert 358 95 30 4 3.16

American { Damascus 694 150 32 6 4.60

Merchantmen. { Rajah 531 140 30 0 4.66

These may, perhaps, be considered the extremes of ship-building; 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.

Tonnage. Full built. Sharp built.

300 (.75) 525 (.00) 300

400 (.80) 725 (.40) 560

500 (1.00) 1000 (.50) 750

600 (1.33) 1400 (.50) 900

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 "Seamen'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.

Fore-mast, eight ninths of the main-mast.

Mizzen-mast, five sixths of the main-mast.

Bowsprit, two thirds of the main-mast.

Topmasts, three fifths of the lower masts.

Topgallant masts, one half the length of their topmasts.

Jib-boom, the length of the bowsprit.

Main-yard, twice the beam.

Fore-yard, seven eighths of the main-yard.

Maintopsail-yard, two thirds of the main-yard.

Foretopsail-yard, two thirds of the fore-yard.

Crossjack-yard, the length of the maintopsail-yard.

Topgallant-yards, two thirds of the topsail-yards.

Mizzentopsail-yard, the length of the maintopgallant-yard.

Royal-yards, two thirds of the topgallant-yards.

Spritsail-yard, five sixths of the foretopsail-yard.

Spanker-boom, the length of the maintopsail-yard.

Spanker-gaff, two thirds of the boom.

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.

Main-mast 74 ft. Head 11 ft. 6 in. Size 26 in.

Fore-mast 70 ft. Head 11 ft. 6 in. Size 25 in.

Mizzen-mast 68 ft. Head 8 ft. 6 in. Size 18 in.

Main and fore topmasts 41 ft. Head 6 ft. 6 in. Size 14? in.

Mizzen topmast 32 ft. Head 5 ft. Size 9? in.

Main topgallant-mast 23 ft. (15 ft. with 2 feet head.) Size 9? in.

Fore topgallant-mast 21 ft. 14 ft. with 2 feet head.) Size 9? in.

Mizzen topgallant-mast 17 ft. 11 ft. with 18 in. with 2 feet head.)

Main and fore yards 60 ft. yard-arms 2 ft. 6 in.

Main and fore topsail yards 48 ft. yard-arms 3 ft. 6 in.

Main topgallant yard 37 ft. yard-arms 2 ft.

Fore topgallant yard 34 ft. yard-arms 2 ft.

Main royal yard 27 ft. yard-arms 1 ft. 6 in.

Fore royal yard 24 ft. yard-arms 1 ft. 6 in.

Main skysail yard 17 ft.

Fore skysail yard 15 ft.

Cross-jack yard 44 ft. yard-arms 2 ft.

Mizzen topsail yard 35 ft. yard-arms 2 ft. 9 in.

Mizzen topgallant yard 25 ft. yard-arms 1 ft. 6 in.

Mizzen royal yard 16 ft.

Mizzen skysail yard 10 ft.

Bowsprit, out-board 27 ft. Size 26 in.

Jib-boom 42 ft. Head 3 ft. Size 14? in.

Flying jib-boom 40 ft. Head 3 ft. 6 in.

Main pole 12 ft., 10 above royal-mast, 5 in. in cap.

Fore pole 11 ft., 9 above royal-mast, 4? in. in cap.

Mizzen pole 9 ft., 7 above royal-mast

Spanker-boom 40 ft.

Spanker-gaff 30 ft.

Swinging-booms 40 ft.

Topmast studdingsail-booms 34 ft.

Topgallant studdingsail-booms 27 ft., yards for do. 17 ft.

Placing the Masts.-For a full-built ship, take the ship's extreme length and divide it into sevenths. Place the foremast one seventh of this length from the stem; the mainmast three sevenths from the foremast, and the mizzenmast two sevenths from the mainmast. If a vessel is sharp-built, and her stem and stern-post rake, her foremast should be further aft, and her mizzenmast further forward, than the rule of sevenths would give. A common rule for placing the foremast, is to deduct three fifths of a ship's beam from her length, for the curvature of the keel forward, which is called the keel-stroke, and place the mast next abaft the keel-stroke.

Size of Anchors and Cables.-Various rules have been adopted for the weight of a ship's anchors. A vessel of 100 tons will generally have a best bower of 6 cwt. and a small bower of 5 cwt.; the weight of both being eleven pounds to a ton of the vessel. As a vessel increases in size, the proportion diminishes. A vessel of 700 tons will usually carry a best bower of 27 cwt. and a small bower of 24 cwt.; the weight of both being seven and a half pounds to a ton of the vessel. The stream should be a little more than one third the weight of the best bower. The anchor-stock should be the length of the shank; its diameter should be half that of the ring, and its thickness one inch at the middle and half an inch at each end for every foot in length. Chain cables are usually ninety fathoms in length, for large-sized vessels, and sixty for small vessels, as schooners and sloops. The regulation of the United States Navy for chain cables, is one inch and a half for a sloop of war, and one and a quarter for brigs and schooners. In the merchant service, a ship of 400 tons would probably have a best bower cable of one and five sixths, and a working bower of one and a quarter inches. A ship of 700 tons would have a best bower of one and five eighths, and a working bower of one and a half inches. Chain cables have a shackle at every fifteen fathoms, and one swivel at the first shackle. Some have two swivels; and formerly they were made with a swivel between each shackle.

Lead-lines.-The hand-lead weighs usually seven pounds, and the hand-line is from twenty to thirty fathoms in length. The deep-sea-lead (pro. dipsey) weighs from fourteen to eighteen or twenty pounds; and the deep-sea-line is from ninety to one hundred and ten fathoms. The proper way to mark a hand-line is, black leather at 2 and 3 fathoms; white rag at 5; red rag at 7; wide strip of leather, with a hole in it, at 10; and 13, 15 and 17 marked like 3, 5 and 7; two knots at 20; 3 at 30; and 4 at 40; with single pieces of cord at 25 and 35.

The deep-sea-line has one knot at 20 fathoms, and an additional knot at every 10 fathoms, with single knots at each intermediate 5 fathoms. It sometimes has a strip of leather at 10 fathoms, and from 3 to 10 is marked like the hand-line.

Log-line.-The rate of a ship's sailing is measured by a log-line and a half-minute glass. The line is marked with a knot for each mile; the real distance between each knot being, however, 1/120 of a mile, since a half-minute is 1/120 of an hour. A knot being thus the same portion of a mile that a half-minute is of an hour, the number of knots carried off while the glass is running out will show the number of miles the vessel goes in an hour. Many glasses, however, are made for twenty-eight seconds, which, of course, reduces the number of feet for a knot to forty-seven and six tenths. But as the line is liable to stretch and the glass to be affected by the weather, in order to avoid all danger of a vessel's overrunning her reckoning, and to be on the safe side, it is recommended to mark forty-five feet to a knot for a twenty-eight second glass. About ten fathoms is left unmarked next the chip, called stray-line. The object of this is that the chip may get out of the eddy under the stern, before the measuring begins. The end of the stray-line is marked by a white rag, and the first knot is forty-five or forty-seven feet from the rag. A single piece of cord or twine is put into the line for the first knot, one knot for the second, two for the fourth, three for the sixth, and so on, a single piece of cord being put in at the intermediate knots.

Ballast and Lading.-A ship's behavior, as the phrase is, depends as much upon the manner in which she is loaded and ballasted, as upon her model. It is said that a vessel may be prevented from rolling heavily, if, when the ballast is iron, it is stowed up to the floor-heads; because this will bring the ship back, after she has inclined, with less violence, and will act upon a point but little distant from the centre of gravity, and not interfere with her stiff carrying of sail. The cargo should be stowed with the weightier materials as near as possible to the centre of gravity, and high or low, according to the build of the vessel. If the vessel is full and low built, the heavy articles should be stowed high up, that the centre of gravity may be raised and the vessel kept from rolling too much, and from being too laborsome. But a narrow, high-built vessel should have the heavy articles stowed low and near the keelson, which will tend to keep her from being crank, and enable her to carry sail to more advantage.