The following are the calculations for the masts, yards, &c. of the ship of 500 tons whose principal dimensions are—
| Ft. | In. | Ft. | In. | ||
|---|---|---|---|---|---|
| Length of keel, | 106 | 6 | Depth of hold, | 22 | 0 |
| Ditto, for tonnage, | 117 | 2 | Housing of the masts, | 20 | 0 |
| Breadth of frame, | 30 | 6 | Length of the load-water line, | 115 | 3 |
| Ditto, for tonnage, | 31 | 0 |
1st, Main-mast, Main Top-mast, &c. — 31 × 3 = 93 + 1-3d of 115 ft. 3 in. = 131.5, and 4-7ths of 131.5 = 75 ft. 1 in. = length of the main-mast; or by rule 2d, which is shorter, 115"3 ÷ 3 = 38.5 + 30.5 × 3 + 20 = 150, and 150 ÷ 2 = 75 feet = length of main-mast; 75 × .3 = 22½ inches, its diameter at the partners; 7.8ths of 22.5 = 19 7/8 in diameter at trestletrees; 2-3ds of 22.5 = 15 in. its diameter at the top; and 75 × .14 = 10.5 feet, the length of the mast head.
Main Topmast, — 4-7ths of the 75 = 42 ft. 10 in. the length of main-topmast; 42"10 ÷ 3 = 14¼, its diameter at the heel; and 2-3ds of 14¼ = 9¾ inches, diameter at the top; and 42.9 × .14 = 6 feet, the length of the head.
Main Topgallant-mast, — 5-9ths of 42"10 = 23 feet 6½ inches, the length; and 23"6 ÷ 3 = 7 7/8 inches, its diameter at the heel; 2-3ds of 7 7/8 = 5 inches, its diameter at the top; and 23.5 x .14 = 3 feet 3 inches, the length of the mast-head.
Main Royalmast, — 4-7ths of 23 feet 6 inches = 13.5 feet the length of the mast from heel to the rigging or pole; 3-5ths of 13.5 = 8 feet 1 inch, the length of the pole; 5-8ths of 7 7/8 inches = 5 inches, its diameter at the heel; 2-3ds of 5 = 4 inches nearly for the diameter at the rigging; and 3-5ths of 4 = 2½ inches diameter at the truck.
Fore-masts, &c. — 14-15ths of 75 = 70 feet, the length of the Fore-mast, and 70 × .3 = 21 inches, its diameter at the partners; 7-8ths of 21 = 18 5/8, its diameter at the trestletrees, and 2-3ds of 21 = 14 inches, diameter at the top; and 70 × .14 = 9.8 feet, the length of the mast-head.
Fore Topmast, — 19-20ths of 42 feet 10 inches = 40 feet 8 inches, the length of the topmast; 40.8 ÷ 3 = 13 7/8 inches, its diameter at the heel; 2-3ds of 13 7/8 = 9 5/8 inches, its diameter at the top; and 40.7 × .14 = 5 feet 7 inches, the length of the mast-head.
Fore Top-gallant, — 19-20ths of 23.5 = 22 feet 6 inches, the length; 22.5 ÷ 3 = 7½ inches, diameter at the heel; 2-3ds of 7½ = 5, diameter at the top; and 22.5 × .14 = 3 ft. 1 in. for the length of the mast-head.
Fore-royal, — 19-20ths of 13.5 = 12 ft. 7 in. the length from the heel to the rigging or pole; and 3-5ths of 12"7 = 7 ft. 7 in. for the length of pole; 5-8ths of 7½ = 4 5/8 in. the diameter at the heel; diameter at the rigging 3¾ inches; at the truck 2½ inches.
Mizen-masts, — 9-10ths of 75 feet = 67"6, the length of the mizen, and 3-4ths of 22.5 = 16 7/8, diameter at the partners; 7-8ths of 16 7/8 = 14¾ inches, diameter at trestletrees, and 2-3ds of 16 7/8 = 11¼ inches, diameter at the top; and 67.5 ×, .14 = 9 feet, the length of the mast-head.
Mizen Topmast, — 3-4ths of 42"10 inches = 32 feet 1 inch, the length; 1-3d of 32"1 = 10¾ nearly, the diameter at the heel; 2-3ds of 10¾ = 7 inches, diameter at the top; and 7-8ths of 10¾ = 9 3/8 inches, diameter at the trestletrees; and 32.1 × .14 = 4 feet 4 inches, length of the mast-head.
Mizen Top-gallant, — 3-4ths of 23 feet 6 inches = 17 feet 7½ inches, the length; 17"7½ ÷ 3 = 5 7/8 inches or 6 inches, the diameter at the heel; and 2-3ds of 6 = 4 inches, diameter at the top; also 17.7 × .14 = 2 feet 5 inches, length of the head.
Mizen Royal, — 3-4ths of 13 feet 5 inches = 10 feet 3 inches, length from heel to the rigging; and 3-5ths of 10 = 6 feet, length of the pole from rigging to the truck; 5-8ths of 6 = 4 inches nearly, its diameter at the heel; 2-3ds of 4 = 2¾ inches, diameter at the rigging; and 3-5ths of 2¾ = 2 inches nearly, its diameter at the truck.
Mizen-boom and Gaff, — 30.6 × 1.2 = 36 feet 6 inches, length of the boom, but may be a little longer, if desired; 36.5 × .23 = 10.3 inches, its diameter at the sheet; 2-3ds of 10.3 = 7 inches, diameter at the tail of the cheeks, and 3-5ths of 10.3 = 6 inches, diameter at the outer end; 2-3ds of 36.5 = 24 feet 4 inches, the length of the gaff; 24.4 × .24 = 5¾ or 6 inches, diameter at the tail of the cheeks, and 3½ diameter at the outer end.
Main-gaff, the same as the mizen-gaff. See the Rule.
Fore-gaff, the same as the main-gaff.
Bowsprit, — 1-3d of 115.3 = 38"6 + 31 = 69"6 ÷ 2 = 34"9, the length of the bowsprit without the stem; diameter at stem 22½ inches, and 2-3ds of 22.5 = 15 inches diameter at the outer end; 4-7ths of 34"9 = 20 feet nearly, the distance of the cleats for the heart of the stay, from the stem.
Jib-boom, — 34"9 + 1-6th = 40 feet 2 inches, length of jib-boom, and 40 ÷ 3 = 13½ inches, diameter at inner end; and 2-3ds of 13 = 8½ inches, diameter at the outer end.
Main-top, — 5-9ths of 31 feet = 17 feet 4 inches, the breadth of the top; 17"4 ÷ 2 = 8 feet 8 inches, the length of the trestletrees; 5-6ths of 20 = 16½ inches, the depth of ditto; and 3-7ths of 16.5 = 7 inches, the breadth of ditto; 17 feet 4 inches, the length of the crosstrees; 7 1/8 inches, breadth of ditto; 6 inches, the depth of ditto.
Cap, — 15 × 3.5 = 4 feet 4 inches, the length of the main-cap; 14¼ × 1¾ = 2 feet, the breadth of ditto; 10 inches, the depth of ditto.
Main Topmast Trestletrees, — 8 feet 8 inches ÷ 2 = 4 feet 4 inches, the length; 10 inches, the depth; 4¼ inches, the breadth.
Main Topmast Crosstrees, — 8 feet 8 inches in length by 4 inches square.
Cap for the Main Topmast, &mdash 9¾ × 3.5 = 2 feet 10 inches, the length; 7 7/8 × 1¾ = 13¾ inches, the breadth, by 6 inches in depth.
Main Top-gallant Trestletrees, — 2 feet 2 inches, the length; 5 inches, the breadth; 3 inches, the depth.
Main Top-gallant Crosstrees, — 4 feet 4 inches, the length; 2½ inches broad by 2 inches deep.
Main Top-gallant Cap, — 4 × 3.5 = 1 foot 2 inches in length; 7 inches in breadth; 3 inches in depth.
The Tops, Trestletrees, Crosstrees, Caps, &c. for the Fore-mast, fore-topmast, fore-topgallant-mast, &c. are the same size as the main-caps, trestletrees, crosstrees, &c.
Mizen Top, &c. — 3-4ths of 17 feet 4 inches = 13 feet in length. Trestletrees 6 feet 6 inches in length; 5-6ths of 14¾ = 12 1/8 inches in depth; 3-7ths of 12 = 5 1/8 in breadth or thickness. 13 feet, the length of the Crosstrees; 10 ÷ 2 = 5 inches, breadth or thickness of ditto; 4½, depth of ditto ditto. 11¼ × 3.5 = 3 feet 3¼ inches, the length of the Mizen Cap; 10¾ × 1¾ = 19 inches, the breadth of ditto; 3-4ths of 10¾ = 8 inches, the depth of ditto.
Mizen Topmast Trestletrees, — 3 feet 3 inches in length; 5-6ths of 7 = 6 inches nearly, the depth; 3-7ths of 6 = 3 inches nearly, the breadth.
Mizen Top-mast Crosstrees, — 6 feet 6 inches in length, 7 ÷ 2 = 3½ inches in thickness, 3 inches in depth. 7 × 3.5 = 24½ inches or 2 feet, the length of mizen top-mast cap; 4 × 1¾ = 7 inches the breadth of ditto; 3 1/8, the depth of ditto,
Mizen Top-gallant Trestletrees, — 1 foot 6 inches in length, 4 inches in depth, by 2 inches in breadth.
Crosstrees, — 3 feet 3 inches in length; 5-6ths of 4 = 3¼ inches in depth. by 2½ inches thick. 4 × 3.5 = 14 inches, the length of the mizen top-gallant cape [sic]; 3½ × 1¾ = 6 1/8 inches, the breadth of ditto; 3 inches, the depth of ditto.
Cap of the Bowsprit, — 15 x 3.5 = 4 feet 4 inches in length; 14 × 1¾ = 2 feet in breadth; 3-4ths of 14 = 10½ inches in thickness.
Main Yards, &c. — 115 + 31 = 146, and 146 × 4/11 = 53 feet 1 inch, length of the main-yard; 53 ÷ 4 = 13¼ inches diameter at the slings; 13¼ ÷ 2 = 7 5/8 diameter at the ends; 53 ÷ 20 = 2 feet 7 inches, length of yard-arms. 53 × 7/9 = 41 feet 2 inches, the length of the main-top sail-yard; 41"2 ÷ 4 = 10¼ inches, diameter at the slings; 10¼ ÷ 2 = 5 1/8 inches, diameter at the ends; 41"2 ÷ 20 = 2 feet, the length of the yard-arms, but may be a little longer if required. 41"2 × ¾ = 30 feet 10 inches, length the main top gallant-yard; 30"10 ÷ 4 = 7¾ inches, diameter at the slings; 7¾ ÷ 2 = 3 7/8 inches, diameter at the ends; 30"10 ÷ 20 = 1 foot 6½ inches, the length of the yard-arms. 30"10 × 2/5 = 20 feet 6 inches, length of main royal-yard, 20"6 ÷ 4 = 5¼ inches, diameter at the slings, 5¼ ÷ 2 = 2 5/8 inches, diameter at the ends; 20"10 &divde; 20 = 1 foot, the length of the yard-arms.
Fore-yards, &c. — All the fore-yards the same size as the main-yards.
Mizen-yards, &c. 3-4ths of the main-yards — 53 × ¾ = 39 feet 9 inches, the length of the cross-jack yard; 39"9 ÷ 4½ = 8¾ inches, diameter at the slings, and 4 5/8 inches, diameter at the ends; 39"9 ÷ 20 = 2 feet nearly, the length of the yard-arms. 42 2 × ¾ = 30 feet 10 inches, the length of the mizen topsail-yard; 30"10 ÷ 4 = 7 7/8 inches, diameter at the slings = 4 inches nearly, diameter at the ends; 30"10 ÷ 20 = 1 foot 6 inches nearly, length of yard-arms. 30"10 ¾ = 23 feet 1 inch, the length of the mizen top-gallant yard; 23"1 ÷ 4 = 5¾ inches, diameter at the slings, and nearly 3 inches diameter at the ends; 1 foot, length of the yard-arms; 20"6 × ¾ = 15 feet 4½ inches, the length of the mizen royal-yard; 15"4 ÷ 4 = 4 inches nearly, the diameter at the slings, and 2 inches diameter at the ends; 9 inches the length of the yard-arms.
Studding-sail Booms for the Main and Fore-yards. — Studding-sail booms for main-yards 53 ÷ 2 = 26"6 + 2 = 28 feet 6 inches in length, 7 and 5 inches diameters; ditto topsail yards, 42 ÷ 2 = 21 + 2 = 23 feet in length, 6 and 4 inches diameters; ditto top-gallant yards, 30"10 ÷ 2 = 15.5 + 2 = 17 feet 5 inches in length, 4 3/8 and 3 inches diameters.
Transcribed by Lars Bruzelius
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© Copyright 2000 Lars Bruzelius.