Understanding information systems

Electronic Chart Display and Information System became one of the main devices on navigation bridge. ECIDS supports navigation by gathering information and automating some process like plotting of position of own ship and other objects on the scene. ECDIS as every equipment has got advantages and limitations. Their understanding should help navigators to perform watches in a safer way. This article presents discussion about some deficiencies of ECDIS. Discussion is underlined by two accidents which show when misunderstanding or overreliance may lead to catastrophic consequences.