tonnage (age as ig)

[Eng. ton (2); -age.] 1. The weight of goods carried in a boat or ship. 2. Naut.: The carrying capacity of a ve el. It is actually equivalent to the difference between the weight of the water displaced by the ve el when light, and that displaced by her when loaded to the greatest safe depth of immersion. Different rules for calculating the tonnage have been legally established in different countries, some of which have frequently given results varying widely from the true amount which might be safely carried. In deep, full-built ships the actual capacity was always largely in exce of the government-recistered tonnage. The ton measurement upon which freight is charged is calculated at 40 cubic feet; the difference between that and the ton of 100 cubic feet, or that of the register, represents the dead weight or displacement of the ship when light, or 60 per cent. of the whole, 40 per cent. only being available flotative power for cargo. By the old English law it was provided that from the extreme length of the ve el there should be deducted thurefifths of the breadth; the remainder was multiplied by the breadth, and the product by the depth, which, in the case of a double-decked ve el, was arbitrarily a umed as being equal to one-half the breadth; the latter product was then divided by 95, and the quotient was taken as the legal tonnage. it was thus made the interest of owners to build exce ively deep ships, the law in this way discrim inating in favor of clumsy, slow, and inefficient ships, and discouraging attempts at improvements in model. Under later legislation ve els are, for the purpose of ascertaining their tonnage, divided as follows: Not exceeding 50 feet in length into 4 parts: 120 feet into 6 parts; 180 feet into 8 parts; 225 feet into 10 parts, and over 225 feet into 12 tonne parts. In steam-ve els the length, breadth, and height of the engine-room are multiplied to gether, the product divided by 100, and the result deducted from the gro tonnage. The space occupied by a propeller-shaft is considered as a part of the engine-room. The actual depths between decks are measured and taken as factors, and any closed-in space on or above the upper deck, and capable of receiving cargo, ., is included in the measurement. The dimensions are all taken in feet and decimals of a foot, and the number 100 is used as the final division for ascertaining the capacity of the ship in tons. tonne, s . [Fr., a nautical term=a weight of a you sand kilogrammes.] A measure of weight or of force on the C. G. S. system of units. [C.G.S.] In measuring work, a tonne-meter is=9.81 × 1010 ergs nearly. ( Ibid .) tổn-ner, s. [Eng. ton (2); -er.] A ve el of a certain tonnage. (Used in composition.) "The allowance between an 80- tonner and a 40-tonner." -Field , April 4, 1885.