1246. RULE 4.-In ascertaining the Tonnage of Open Ships, the upper edge of the upper strake is to form the boundary line of measurement, and the depths are to be taken from an athwart ship line, extended from upper edge to upper edge of the said strake, at each division of the length. 1247. Builder's Measurement. In disposing of their ships, builders generally adhere to the law of 1773, which enacts that The length shall be taken in a straight line along the rabbet of the keel, from the back of the main stern-post to a perpendicular line from the fore-parts of the main-stem under the bowsprit. The breadth also shall be taken from the outside of the outside plank, in the broadest part either above or below the main wales, exclusive of all manner of doubling planks that may be wrought upon the sides. Three-fourths of the breadth to be deducted from the length. Multiply the remainder by the breadth and that product by the half-breadth, then divide by 94. If the ship be afloat, the directions are, "To drop a plumb-line over the stem, and measure the distance between such line and the after-part of the stern-post, at the load water mark; then measure from the top of the said plumb-line, in a parallel direction with the water, to a perpendicular point immediately over the load water mark at the fore-part of the main-stem: subtracting for each admeasurement the above distance, the remainder will be the ship's extreme length, from which is to be deducted three inches for every foot of the load draught of water for the rake abaft; from the length, taken in either of the ways above mentioned, subtract three-fifths of the breadth taken as above, the remainder is esteemed the just length of the keel to find the tonnage; then multiply this length by the breadth, and, dividing by 94, the quotient is deemed the true contents of the lading." 1248. The common rule for finding the burthen of ships by this mode is, to multiply the length by the extreme breadth, and that product by half the extreme breadth, and divide by 94, thus ; length x extreme breadth × half the extreme breadth × 94 builders' tonnage. = 1249. Another authority says multiply the length of the keel taken within board, by the breadth of the ship within board, taken from the midship beam, from plank to plank. Multiply the product by the depth of the hold, taken from the plank below the keelson to the under part of the upper deck plank, and divide the last product by 94; then the quotient is the content of tonnage required. A practical builder says: "Subtract three-fifths of the main beam from the length for tonnage, viz.-length of keel and rake of stem. Multiply the product by the beam, and then by half the beam, and divide the remainder by 94, which will give her old tonnage. The beam for old tonnage is taken at the greatest external breadth, either above or below the thick plank of the main wales, but not on the wales." 1250. In builders' measurement it matters not how deep a vessel is nor how many deck-houses she may have. As a rule the builders' measurement gives a greater tonnage than the register. Four schooners belonging to the South Devon Shipping Company by builders' tonnage measured 877 tons, by register 589 tons n.n.m.; these vessels carry in the summer, dead-weight cargo 934 tons, and possess good sailing qualities. As a general rule a ship of 100 tons register will carry a cargo weighing 150 tons; some ships registering say 500 tons may carry a general cargo of 1,000 tons. It is held that if an owner wants a good vessel, he can stipulate for payment by registered tonnage, coupled with classification in LLOYD'S Register; and that this will be a surer test than buying by length and breadth only, irrespective of depth or form. If an owner paid for registered tonnage, he would get 109 cubic feet for every registered ton. Owners consider that, if a vessel will not carry more than her register, she is unprofitable; and it is known that a ship can be built with lines so fine that it would be imprudent to load her to her registered tonnage. This, however, applies mostly to vessels built for fast steaming or sailing, irrespective of dead-weight capacity. For sailing vessels it is easy to lay down a standard, but the requirements of steamers render a general rule difficult. It is time however, to abandon the obsolete law of 1778 in the building and purchase of ships, for it cramps the energy of designers, and has produced a discreditable class of ships. To keep pace in the present race, owners should discard the purchase by builders' measurement, and adopt the law of 1854; the builders will then be in a position to still further improve the style of naval architecture. Some ships built in the United States and British provinces, take more weight in cargo in proportion to tonnage, through the lightness of material used in the construction.* FOREIGN TONNAGE.-Austria. Of steam-ships (340) the English ton is equal to the Austrian (30 cent. being allowed for the engine and coal-room), but of sailing ships, the Austrian tonnage exceeds the English register ton; about 47 soldi (11d.) are paid from foreign ports, and about 37 (83) from Austrian ports. Brazilian tons are often calculated to exceed the British register tonnage by one-third. * Formerly the 64 shares into which a vessel was divided, were considered equal to lb, avoirdupois; the owner of four shares being called the owner of an ounce, of two shares half an ounce and so on. This resembles the crucial division among the Romans. See Cicero Pro Cœcira VI., sec. 17 China. Rules for calculating the tonnage dues payable upon Continental vessels : 1.—If the vessel be provided with a British certificate of measurement, dues are to be charged in accordance with the tonnage therein specified. 2.-Bremen and Hamburg: four lasts are equal to nine register tons. 3.-Holland: four lasts are equal to seven register tons. 4.-Denmark: four lasts are equal to about eight register tons. 5.-Prussia, Sweden, Norway, Lubeck, Mecklenburg, Hanover, and Oldenburg: four lasts are equal to six register tons. 6.-Austria: four lasts are equal to three register tons. The powers which have treaties with China are Great Britain, France, the United States, Russia, Prussia, and Denmark. Denmark. A Commercial Last is equal to 80 cubic feet Danish. 100 feet Danish=97 feet English, or 5,200 lbs. Danish. 90,7 tbs. Danish=100 lbs. English. As an approximated reduction usually applied to brigs and larger vessels, 1 Danish commercial last is equal to 2.10 tons English. For smaller vessels 1.99. A notice, dated Board of Trade, 11th April, 1868, authorizes the ships of Denmark, the certificates of which are dated on and after 1st October, 1867, to be of the tonnage denoted on their certificates. France fixes the tonnage by three dimensions, the total of which is divided by a certain figure. There is very little difference between the tonnage of the two nations. An experienced firm in London says, 9th August, 1866, "It is seldom we are enabled to get French ships measured here under rule 1, as they have almost always some portion of their cargo remaining on board, or are unable to stand without ballast, when it becomes necessary to have them measured externally. As a rule we expect a French ship to measure rather more here than in France, for there they make an allowance for the poop and all houses above deck, whereas our officers do not. For your information we annex the measurement of several French ships which we have had to our address." The above gives a total of 2,694 English tons register to 2,654 French; this result is used in the following general table, page 733]. Genoa. Vessels with their draught of water painted on the bows or stern pay for the highest mark, and not for what they may actually draw. There are steam-tugs, but they have no fixed tariff. The anchorage dues on sailing vessels and steamers are 50 cents p ton. Vessels loading outwards marble or other goods, require stevedores, who are appointed by the merchant at the ship's expense, and marble costs 4 francs 1 tons stowage; other goods 1 franc ton measurement. Germany.-Lubeck. A Last for sea-going and sharply-built vessels is 4,000 lbs. ; flat-bottomed open vessels 5,000 lbs. Vessels plying between Lubeck and Schonberg 6,000 lbs. Greece. One ton of a Greek merchant vessel is equal in weight to 2,000 French kilogrammes, which are reckoned to occupy 42 cubic feet, so that a vessel of 8,400 cubic feet would be of 200 tons. Some say 100 tons English=0.76 Greek. Hanover. An English ton register may be assumed to be half a Hanoverian last. Many statements have been regulated by the Bremen last, 4,000 lbs. 4,400 lbs. English, or about two tons English 4,480 lbs. = Holland. ARTICLE 3. Every ton of a sea ship is considered to equal 1,000 Netherland lbs. or 1 cubic ells. MEASUREMENT OF THE TONNAGE OF SHIPS. 1 Kubicke Ellen=1 Scheepston = 52.9755 cubic feet. Italy. In steam-ships the English ton has an advantage of about 10 cent., 40 cent. instead of 30 cent. being allowed for the engine and coal room; the charges are, therefore, about 49 cents, equal to 4 d. per ton. Steamers may also pay the charges for one year on payment of 1.50 lire for light dues, and 50 cents for health dues. In sailing vessels the English ton is equal to the Italian, and pays for health dues 20 cents, and light dues 50 cents-together 70 cents, or about 611d. Mexico. The tonnage is similar to the Spanish. Vessels arriving in Mexican ports pay harbour dues at per ton as per Burgos measurement. The following table must, for several countries, be accepted only as an approximation of the relative tonnage. In some foreign states deductions are made for deck-houses, in others none. In some few places the tonnage rates are regulated by the number of the masts of the ship. Under the heading Lastage there may be some information applicable to the tonnage of vessels. |