On Calculating System for Loading Condition by a Simplified Method

Abstract

For the ship's master, the planning of loading condition of the ship is very important in view of the operation and the structural strength of the ship. In the regulations of International Convention on Load Line, 1966, it is provided that the loading and ballasting of the ship are such as to secure the avoidance of excessive structural stress. Usually, the builders supply "Loading Manual" to the ship for this purpose, but manual calculation takes much time and the results may not be accurate enough for every loading condition when compared with those calculated by using a large computer. Recently, instead of "Loading Manual", a mini computer is provided to the ship for calculation of draft, trim, shearing force and bending moment. From the stand point of low cost and easy operation, a mini computer may be most suitable for these systems, but it has a limit in volume of data and programs. Consequently, it is required to find out a simplified method that functions within the above limit, having a sufficient accuracy for practical usage. In this paper, a simplified method, which is suitable for this kind of calculation, is reported as summarized below. (1) Bouyancy and bouyancy moment can be represented by a function of draft and trim. (2) Draft and trim can be represented by a function of the weight and weight moment of the ship. In addition, the outline of the hardware system, which is developed on the basis of the above simplified method, is presented.