Lifting Solutions On FPSO for Life Raft Davits

Background

To accommodate increased personnel on a high-output FPSO, our client initiated an expansion of the living quarters. This expanded capacity necessitated an upgrade in the FPSO’s lifesaving appliance capacity, specifically the lifeboats.  This subsequently required an upgrade of the existing lifeboat davits.

Calling a lift vessel or barge to perform the lifting work was an option, however it is an expensive one.  In addition, the installation work would require stable and precise lifting – this would be difficult to achieve with a barge crane due to the double-dynamic situation at sea.   The modular crane option proposed by Thunder Cranes was considered the most feasible and cost-effective solution.

Challenges & Solutions

• Skidding: No major skidding or transferring across deck required. Only routine skidding of crane components in the process of rigging up.
• Rigging up: Our self-lifting system was required in order to rig up the TC15. Thunder Cranes provided a TC05 crane as the assist crane for the rig up.
• Modifications: Due to the absence of accessible structural members for our clamping system, we helped our client to design foundations that were welded to the FPSO deck. On these foundations our crane would be installed and at the same time they would help strengthen the deck to handle the reaction forces imparted by the cranes during lifting operations.
• Tie down method: Bolting to pads.
• Max Lift: 11MT (Offboard) with the TC15.

Timeline / Steps

1. Welding of pads on the FPSO deck for the TC05 and TC15 tie down.
2. Lifting the components of our smallest crane from supply boat to FPSO lay-down area via the FPSO 2 ton jib crane.
3. Rigging up the components of TC05 and securing the TC05 on the pads via bolting, followed by load testing.
4. TC05 assembled and securely tied down in position to lift the components of TC15 from the supply boat.
5. TC15 assembled with assistance of the TC05, and securely bolted down on the pads, followed by load testing.
6. TC15 assisting with removal and repositioning of existing davits & 76 personnel life raft from 1st deck house to FPSO main deck.
7. TC15 lifts new larger davit arms from supply vessel. Davit arms are installed on the fly due to space constraints on FPSO. TC15 lifts new 130 personnel life raft from supply vessel to FPSO for installation.
8. TC05 & TC15 Rig down and backload to supply vessel, crew demobilized and transferred back to shore base.