A Treatise on the Stability of Ships ¹

Abstract

II. IN simplifying the mode of presentation of the scientific principles which govern the stability of ships, Sir E. J. Reed touches upon a very important point the defects of nomenclature. The technical nomenclature of naval architecture has gradually been formed in an unsystematic and often heedless and unintelligent manner; and it contains many inconsistencies and inaccuracies. Attention has previously been called by ourselves and others to the subject. Sir Edward Reed refers to the confusion that is sometimes caused by giving the name “metacentre” to points upon two curves which are quite distinct from each other. One of these curves indicates the variation in the height of the metacentre with draught of water when the ship is upright; and the other is that formed by the intersections of consecutive normals to the curve of buoyancy as a ship becomes inclined from the upright. These two curves are entirely different in character, and have only one point in common-viz. the metacentre for the upright position corresponding to the draught of water for which the curve of intersections of consecutive normals is constructed. The latter curve is, of course, the evolute of the curve of buoyancy. Sir Edward Reed proposes to call the intersections of consecutive normals to the curve of buoyancy at all angles of inclination from the upright “pro-metacentres,” and to restrict the use of the term “metacentre” to indefinitely small inclinations from positions of equilibrium.

A Treatise on the Stability of Ships.

By Sir E. J. Reed (London: C. Griffin and Co., 1885.)