To provide a height controlling device for towing a towing object for sonic prospecting by a ship.
This height controlling device for a towing object is equipped with a target depth calculator 120, a towing rope hoisting amount calculator 130, and a hoist starting time calculator 140. The target depth calculator calculates the values of height upper and lower limit functions which are obtained by adding upper and lower allowable ranges to seabed topographic data, judges a possibility for the occurrence of an interference by comparing the height upper and lower limit values and the present depth of the towing object, and sets a target depth at the interference time and at the interference point and after when the interference occurs. The towing rope hoisting amount calculator calculates the log speed of the towing object and a towing rope hoisting amount for a depth alteration of the towing object from the target depth, the present depth and towing rope length, referring to towing object response characteristic database. The hoist starting time calculator obtains a towing object response time from the present towing rope length, the log speed of the towing object, and the towing rope hoisting amount referring to the data base regarding the towing object response time, and calculates the hoist starting time by advancing the interference time by the response time.
SUEOKA YOSHIAKI
NAGATA MASAYUKI
TSUTSUI SHIGERU
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