Method for constructing a very large turret mooring arrangement

摘要

A method for constructing and installing a very large turret in a vessel without lifting the entire turret from a fabrication yard into the moonpool. According to a first alternative method, both the lower part and the upper part of the turret are constructed inside the moonpool while the vessel is in drydock. Such method obviates providing very large lifting cranes capable of lifting the entire turret including the upper part of the turret and the lower part into the moonpool. According to a second alternative embodiment, the turret has an upper part and a lower part and the lower part is constructed in the moonpool while the vessel is in drydock, like in the first alternative method. In the second embodiment, the lower part is supported by rods and jacks from the moonpool, and the vessel is floated out of drydock into the water and parked at dockside. The upper part of the turret is then lifted in place with a crane of moderate size and connected to the lower turret part with bearings installed between the upper part and the moonpool.