WAVE LOAD DISTRIBUTIONS ON LARGE SHIPS

The role of new ship requirements in promoting technological advances in ship design and operation is discussed, with special reference to the effects of the environment on loading and responses and to the determination of design values and operational criteria. Three types of ship response are selected for more detailed discussion, all related to the distribution of hydrodynamic loads on ships in waves: (1) bending moments; (2) accelerations; and (3) pressures. Bending moment trends of VLCC's and containerships are illustrated, showing the effect of ship length and shape on the trends and their magnitude. Accelerations are discussed with reference to the determination of inertia forces on various structural members and mechanical components, and trends with ship length and type are also shown. The effect of phase angle between ship motion and acceleration response is also discussed. The use of a detailed external pressure distribution on the hull as a means of inputing loads for structural analysis is given along with the theoretical model required to calculate these pressures. A scheme for determining the pressure at any point on the ship surface is given and a short discussion of transient effects is presented. The effects of these responses on the operation of the ship and on decisions made by the officer on the bridge is discussed in relation to onboard heavy weather hull surveillance systems.