| 摘要 |
1511235 Propelling semi submersible rigs D J DOUST 18 June 1975 [19 June 1974] 27195/74 Heading B7V A semi submersible rig comprises a plurality of pontoons which support a working deck and at least one of the pontoons has a propulsion and steering unit at each end comprising a Y-shaped duct 22 arranged with two arms 23 opening into the sides of the pontoon and a stern 24 opening into a rudder recess 29 in a respective pontoon end, rudder means in the recess, valve means in each of the arms 23 and a propeller 36 in the stern 24. As described the rudder means comprise twin rudders 30 and the valve means comprise butterfly valves 31. Ballast tanks and drive motors 32 are arranged in the pontoon. |
