Navigation aid e.g. for ferry-boat using guide wire - has on-board device cooperating with latter to indicate distance and direction of opposing landings

摘要

The navigation aid for repetitive return journies between two landings comprises a wire which is strung between the latter. The wire is around around a capstan on board the boat controlling a counter indicating the distance travelled. The capstan has two arms each contacted by the wire causing them to pivot coaxially about the capstan through angles which are monitored to indicate the directions of each landing, so that deviations from the required course can be detected. Pref. the wire has two strands each extending between one of the landings and a storage reel on the boat. Each reel is driven by a planetary mechanism of a differential, with coders detecting the rotation of each reel. The two arms are associated with respective reels and have guides for the wires. The aid is used for a ferryboat etc.