Seaway and Octopus as a study tools for ship motions

The engineers are interested in the theoretical and practical ways by which, in the activity of design, construction and operation of the ship, the complications generated by the sea waves can be overcome. The paper presents some examples regarding the possibilities of com-puter-assisted study of characteristics that define the behaviour of the ship under navigational conditions (linear and angular amplitudes of movements, energy spectre of response to different positions of the ship in relation to the incident waves). The study, carried out for a container vessel, took into account the different operating speeds of the ship and rudder angles. Was used features offered by two tools for modelling and simulation - OCTOPUS and SEAWAY - software that allows the study of the computerized behaviour of the ship on the waves in the real navigational conditions. Program library was used for both the ship and navigation environment (modelled using Jonswap energy spectrum).