The ship operability can be understood and analysed in different manners, and its quality is described using different indexes by different authors. Practically, there is no general and widely accepted description of total ship operability in the literature, nor in the rules of classification societies, which would include both seakeeping and manoeuvrability characteristics of a ship, and simultaneously take into account all ship subsystems and, what is most important, comfort and safety of people on board. The aim of this paper is to propose a general definition of total ship operability and name, adjust, describe and justify criteria which should be considered in the ship operability analysis, as well as to provide a relevant algorithm paving the road for further investigation on total ship operability determination.
The paper presents a new concept of overall ship motion modelling for application to total ship operability. The delivered model is a multi-phase and includes both submerged part of ship’s hull and the surrounding water as a unique body. The Discrete Finite Element Method is applied. The model is successfully examined and illustrated for a selected AHTS