Note 9 — Chapter IV · PROGRESS IN THE SCIENCE OF SHIPBUILDING.

Suppose the dimensions of a proposed vessel to be 320 × 36 × 26½ feet, then, according to a method of approximation largely in use, the sum of these dimensions divided by 100 gives what is known as the “cubic number”—(320 × 36 × 26½ ÷ 100) = 3052 cubic number. Suppose that for a vessel already built, similar in type and dimensions, or of similar proportions, to the one proposed, the cubic number, when divided into the ship’s actual weight (i.e., the displacement minus the weight of machinery and the dead-weight carried), gives say ·53, then this figure represents the “co-efficient” of ship’s weight, and applying it in the case supposed gives:—3052 × ·53 = 1620, the weight of hull for proposed vessel. This example illustrates the manner in which the weight of machinery is estimated, and indicates the nature and use of the general term “co-efficient:” frequently employed in this chapter.