An ever increasing traffic density and the larger dimensions and higher speeds of modern ships all make the task of navigating and manœuvring a vessel more difficult. To make the task easier more emphasis has been placed on the human engineering aspects in the design of navigation bridges and on automation. Increasing automation has changed the man-machine relationship, in particular man is relegated more and more to a monitoring role; predictions about the ultimate of automation, the unmanned ship, have not yet come to pass but the increasing importance of the bridge as a result of automation is certainly recognized. However, to understand the process of steering not only must the layout of the navigation bridge be studied but also the visual impression of the external environment. It is obviously important to adapt the conditions of the working environment to human aptitudes, for this is the only way to enable man to correct and control the system in complex situations. But such an approach demands a general knowledge concerning human aptitudes and it is necessary to study a man's behaviour in varied situations to discover his inherent limitations.