Mooring of Surface Vessels to Piers
This paper presents a new analytical method of determining the tension forces in mooring lines of surface vessels. The method will aid the ship designer in developing fixed mooring systems with more accuracy than in the past. The analytical model developed considers the hull to be rigid and restrained broadside to a shallow-water pier with resilient fenders in use. The approach to the problem involves (a) determination of wind, current, and equivalent static wave forces at specified headings; (b) calculation of buoyant restoring forces caused by trim, heel, and immersion of the hull; (c) derivation of a combined mooring line stiffness matrix in terms of direction angles, lengths, cross-sectional properties, and nonlinear modulus of elasticity; and (d) derivation of generalized stiffness matrix for fixed mooring system and determination of tension forces in mooring lines using matrix algebra procedure and incremental load method. Special emphasis is placed on the cumulative elastic behavior of the mooring lines and on the manner in which the elasticity of the lines controls the vessel movement.