| 摘要 |
A semi-submersible crane vessel has means for levelling the vessel to compensate for variation of a load carried by the crane, said means comprising a chamber 3 and a piston 4 movable between a position below the water level of the vessel and a position at least level with the water level of the vessel. A valve 20 allows water to enter the chamber above this piston when the piston is in its lower position and a valve 27 allows water to leave the chamber when the piston is raised. A valve 26 allows compressed air to enter the chamber below the piston whereby the buoyancy of the vessel is varied. <IMAGE> |
