| 摘要 |
A semi-submersible crane vessel has a chamber (3) which is open to the sea at the bottom. A piston (4) is movable up and down in the chamber by means of hydraulic jacks (5 and 6) acting on piston rod (7). The part (10) of the chamber above the piston contains air, which may be pressurized via air valve (13) to balance the pressure on both sides of the piston. To stabilize the vessel during movement of a load on the crane (2), the piston is moved in the chamber. This alters the underwater volume of the vessel and therefore its buoyancy. |
