Heavy-lift vessel completes first DP float-over for CNOOC

摘要

A dynamic positioning (DP) float-over occurs when the topside of a platform secured on a heavy-lift vessel or barge is placed on top of pre-set platform legs (jacket) by driving the vessel into position utilising DP mode. The vessel is then held in place utilising the DP joystick to keep the vessel firm against the jacket legs. It is then ballasted to allow the topside to sit on top of the legs. Once the topside is clear of the vessel, the vessel will then drive out and away. An alternative technique to this process usually sees the unit to be installed brought into position on a barge, which requires a number of tugs, mooring arrangements and many riggers to complete the same procedure. Alternatively, the installation can be undertaken using a heavy-lift crane vessel, but as topsides get larger, this option is diminishing.