<；P>；PROBLEM TO BE SOLVED: To accurately and efficiently immerse a large-scale structure in a sea area in a great water depth. <；P>；SOLUTION: A heavy structure 14 is hung in the hanging frame 18； at least the position of a boom top of a crane 16 of a crane barge is grasped by a GPS 52, and shifted to the installation target point of the heavy structure 14； and the settling of the heavy structure 14 is started. A signal of a transponder transmitter 26 is received by a transponder receiver 48； and the position of the heavy structure 14 hung in the hanging frame 18 is constantly grasped during immersion operations. After it is checked that the heavy structure 14 reaches the bottom of the sea within the allowable range of the installation target point, the release hook 22a of an ultrasonic operation-type separation device 22 of the hanging frame 18 is opened by the operation portion 50 of the ultrasonic operation-type separation device 22. Thus, the wire rope 24 slung on the heavy structure 14 is untied； and the heavy structure 14 is released from the hanging frame 18, and immersed on the bottom GL of the sea. <；P>；COPYRIGHT: (C)2011,JPO&INPIT
