Conbit proposed a modular lifting solution for the installation of four accommodation containers on FPSO Baobab MV10, located offshore of Ivory Coast.
Each of the 16t containers would be lifted from a supply vessel onto the FPSO using a gantry system incorporating high speed winches, and then skidded into position.
After the supply vessel is secured in position alongside the FPSO, the lift line is lowered and connected to the sling, which is connected to the accommodation module. The line is then tensioned to begin the lift. The initial few meters of lifting are at high speed to overcome any motion from the supply vessel. Tag lines assist with controlling the load during the lift.
The first accommodation module is lifted to the correct height by the winches and then moved horizontally towards the deck by luffing the gantry. Once the container has reached the appropriate position, it is rotated by 90° so that it can be manoeuvred between the bumper frame and gantry legs and onto the deck. Then the container is lowered onto the deck by releasing the lift line.
Sliding pads are installed underneath the container so that it can be connected to a skidding system. The second accommodation module is then lifted in a similar way and lowered on top of the first, where it can be secured. Both modules are skidded into position.
The accommodation modules are jacked-up so that the sliding pads can be removed and then secured in their final position.
This procedure is repeated for the third and fourth modules, with the gantry structure and its interface connections removed to enable the final positioning.
ALTERNATIVE LIFTING SOLUTION
As well as enabling operations to be planned in greater detail, Conbit’s gantry lifting solution provides the opportunity for more efficient installations on FPSOs as their use continues to expand. As this alternative lifting solution avoids the need for large and expensive crane vessels, it offers significant cost savings to FPSO projects.