MEASURING INSTRUMENTS FOR PILOTING SHIPS WHEN DOCKING AT OR LEAVING SEA BERTHS

摘要

1321505 Digital measurement of distance and Speed TOKYO KEIKI KK and NIPPON SEKIYU KK 4 Aug 1971 36588/71 Heading G4H [Also in Division H4] As a navigational aid for a ship 5 docking at or leaving a sea berth 3, the ship's speed and distance relative to at least one submerged sonar transducer 7 on the berth are measured digitally. In the embodiment shown the distances of the bow and stern from two respective directional transducers set back a distance d from the berth edge are measured by respective pulse-echo sonars 9. Each distance is determined by counting clock pulses passed from a generator 26 to a counter 27 through a gate 24 which is (a) opened by each transmission trigger pulse applied to the gate via a delay 25 to compensate for the offset d, and (b) closed by the subsequent ship echo pulse. Offset d ensures that there is no measurement dead zone arising from the finite transmission pulse width. The ship's speed is measured by comparing two successive distance measurements (e.g. made one second apart) in an up-down counter 30. The counts of counters 27 and 30 are fed via memory circuits 28, 31 to indicators comprising an electric display board on the berth, are radioed to the ship, and may be printed out.