In recent years, casualties at sea have occurred frequently due to the overcrowding of sea traffic, especially on major routes or in harbors, and to the increase in ship size. This has become a serious social problem not only as regards disasters at sea but also in view of environmental pollution. Under such circumstances, a ship maneuvering simulator for the research into the safe sea traffic or the training of crew has stood keenly in need.The authors have constructed a visual maneuvering simulator which can recreate the similar conditions as appearing to a navigator on board a ship. The most sophisticated factor from a technical point of view is to produce a visual display system which can project the prospect looked over from a wheel-house and a target ship in motion as they actually appear. This can be accomplished only by integrating the following three factors; (1) a simulation program which can compute the precise motions of ships of any type, together with the influence of waves, winds, currents, etc., (2) an optical instrument system which can display a variety of changing images on a screen and (3) the servo control system which connects the former two in a. high degree of precision and controls with dead slow action in concert with the ship motion.A whole aspect of the simulator is outlined herein with some examples of its application.