| 摘要 |
1310142 Offshore structures TRANSWORLD DRILLING CO 11 Aug 1970 [1 Dec 1969] 38672/70 Heading E1H A buoyant hull 12 carries a platform 24 for a drilling derrick 26 and is supported above the water when in situ by buoyant columns 14, 16, 18, 20. Each column can be flooded for ballasting purposes and can be locked or moved vertically and independently relative to the hull by mechanisms in housings 30, 32, 36, 38. A buoyancy tanks 46 are secured to the foot of each column. Frameworks 40, 42 connect the housings 36, 38 to the hull. As shown in Fig. 2, while being towed or self-propelled to or from the site the structure floats with the hull and the tanks in the water. The structure may be prevented from drifting when in situ by lines 44 or propelling means (not shown). As shown in Fig. 6 the frameworks may be modified so that the tanks on the columns 18, 20 can be above the water so as to reduce drag when the structure is in transit. (For Figures see next page) |
