In this study, we tackle with one single effort, three fundamental problems in ship hydrodynamics, namely the attraction force exerted on a single ship moving rectilinearly close and parallel to a rigid wall (berthing), the determination of the associated added-mass coefficients (maneuvering) and finally evaluating the forces exerted on a ship in a two-ship crossing scenarios. The novelty of the present approach relies on using Weinblum’s proposition to assimilate the ship’s hull by an equivalent tri-axial ellipsoid, as well as the employment of ellipsoidal harmonics expansion techniques.