METHOD FOR OVER-WATER HOISTING AND POSITIONING SEMI-SUBMERSIBLE SHIP BALLAST TANK

摘要

Disclosed is a method for over-water hoisting and positioning a semi-submersible ship ballast tank. The method comprises the following steps: S10, dividing a ballast tank into several blocks at a general assembly site; S20, pre-measuring levelness of a main deck used to carry the blocks, assigning an installation line and determining an installation position of the block; S30, assigning, according to the measurement of the levelness, a lower margin line for the block, and pre-cutting a margin for the block on the ground; and S40, after a semi-submersible ship is floated, adopting two cranes alternately to hoist the block to the installation position and fixedly install the same. The method of the present invention achieves precise positioning of the installation position of the blocks on the main deck. Further, after the semi-submersible ship is floated, a crane of a dockyard can be used to over-water hoist and position a ballast tank, and since an unsupported part at a stern portion of a ship body is supported by water ballast, the invention avoids a sinking-type deformation of the stern portion structure affecting shaft system precision of the semi-submersible ship.