DREDGER

PROBLEM TO BE SOLVED: To fix an upper part turning body with a working device and the like easily in a detachable state onto a deck of a hull using a land construction machine such as a hydraulic shovel as it is. SOLUTION: A support frame 34 with a round drum 35, each leg part 36, and the like is formed using a center frame of a hydraulic shovel. Each screw seat 33 is fixedly provided on a deck 31A of a hull 31, in a position corresponding to each leg part 36, by welding or the like. A fitting plate part of each leg part 36 is removably fixed in a positioned state onto each screw seat 33 through each fixing bolt 9. Each reinforcing plate is erected on the deck 31A, in a position to be the peripheral side of each screw seat 33 so as to regulate the longitudinal and lateral dislocation of the support frame 34 jointly with each fixing bolt 9. An upper part turning body 11 and a working device are provided in a turnable state on the round drum 35 of the support frame 34 using the upper part turning body and working device of the hydraulic shovel.