Improvements in and relating to the determination of the stability and trim of ships under various load conditions

摘要

1,067,590. Determining stability and trim. INSTYTUT MORSKI. Sept. 29, 1964 [Oct. 1, 1963], No. 39566/64. Heading B7M. [Also in Division G1] The stability and trim of ships in operation under various load conditions in compliance with general stability standards are determined by expressing these standards graphically for a given ship in the co-ordinate system (M, #), where M is the vertical moment and # is displacement, as a function M L =f(#) expressing the dependence, of the vertical limiting moment M L on the ship's displacement #, and plotting on the same diagram points M s whose coordinates represent the characteristic data for the load conditions under test, i.e. the displacement and the vertical moment, whereby the position of the point M s relative to the curve M L =f(#) determines the stability of the load condition under test in relation to the stability standard. Similarly a point M T can be plotted on a curve expressing longitudinal stability, the co-ordinates being M x (longitudinal moment) and #. The slope of the line joining M s to its origin indicates the height of the C.G. The position of the point M T can be used to ascertain the longitudinal position of the C.G. and the trim of the strip. The positions of the points M s and M T are governed by the displacement and vertical and longitudinal moments of the unloaded ship and the additive effects of loads due to equipment, cargo &c. placed on board. These effects are determined at various convenient places or sending sections and conveyed to a device which plots the point M s or M T on the corresponding stability diagram. The conveying means may be mechanical (Fig. 8, not shown) in which the said effects are obtained via gearing, or electrically in which said effects are obtained via electrical resistances.