Engineering Wonders of the World
Volume I

DESIGNING A SHIP. 351 to ensure seaworthiness and lessen the prob- ability of foundering in bad weather at sea. In the case of British merchant vessels, the Legislature, as represented by the Board of Trade, has stepped in to prevent overloading, the result being a notable diminution in the quired. Some idea of the complexity of the problem will be gained by considering briefly what those other qualities are. Often the length or breadth of a proposed vessel is limited by considerations of dock and harbour accommodation, while more frequently a Fig. 2.—A COMPLETED WAX MODEL. number of losses at sea. The primary con- sideration therefore in designing a new vessel is to provide displacement to float the ship and cargo, the freeboard being on no account less than that required by the Board of Trade. The process of fixing the dimensions neces- sary for this purpose is a tentative one, successive consideration of the various factors involved requiring modifica- tions and adjustments until the necessary equality between the displacement and the weight of the ship and cargo is attained, in conjunction with the other qualities re- Choice of Dimensions. governing factor is the limited draught of water available in certain ports. Apart from the question of carrying a certain weight of cargo, sufficient internal space must be pro- vided to contain that cargo, supposing it to have the smallest density probable in the trade for which the vessel is intended. A similar factor enters into the design of pas- senger ships, in that sufficient deck area must be provided for the passenger accom- modation. Further, the new vessel must have ample stability—that is, tendency to remain in an upright position; she must possess the requisite strength in conjunction with a suitable structural design and economy