But also for a simple vessel I recommend to use this method. In those situations the standard formulation of hydrostatic stiffness becomes extremely complicated. Especially if the vessel is composed of multiple elements such as cranes, cargo is placed on it or lifted from it or multiple vessels elements are interconnected. This may sound difficult but it actually makes many things a whole lot easier. It also introduces an alternative way of modeling the hydrostatics by removing the gravity effects from the stiffness matrix. This guide presents a step-by-step guide for setting up a vessel with first order diffraction data from orcawave. Setting up the vessels for such a model using orcaflex is easy but not trivial, but in the end it is just book-keeping. Many offshore operations can be modeled using first order time domain analysis.
