To allow the arrangement of a chute for collecting dropped ores to correctly follow the fluctuation of the tide level and the draft position while avoiding any contact with a hull.
A two-stage chute 11 for collecting dropped ores during the unloading is installed, and the length of an upper stage chute 11b is set so that the upper stage chute can cover the space between the hull 9 and a wharf 1 when it is inclined forwardly to the hull 9 side from an upright state. When starting the unloading, the vertical position of the hull 9 is estimated according to the distance L1 to the hull 9 to be detected by a distance sensor 21, an electric winch 12 is unwound according thereto, and the upper stage chute 11b is inclined forwardly thereby. Thereafter, when the hull 9 is gradually afloat as the unloading work is proceeded, the distance L1 to be detected by the distance sensor 21 is gradually smaller. The target angle of inclination of the upper stage chute 11b is reduced according thereto, and the electric winch 12 is wound to gradually erect the upper stage chute 11b.
IDA TAKASHI
Yoshiaki Naito
Cui Shu Tetsu
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