This publication compiles the lecture notes from the 19th WEGEMT School: Numerical Simulation of Hydrodynamics: Ships and Offshore Structures. The School was held at the Ecole Centrale Nantes, Nantes, in 1993. Some of the topics covered include: Hydrodynamic Problems of Offshore Structures; CFD applications in ship design; Prediction of ship rudder-propeller interaction using a panel method; Second-order hydrodynamics applied to moored structures; Seakeeping and manoeuvring of ships; Viscous flow simulation: State-of-the-art and future trends; and Critical analysis of turbulent viscous flow simulations. The lecture notes have been prepared by several authors, C Berhault, V Aanesland, G Jensen, G Caprino, S Tumock, L Larsson and V Bertram, to name a few.