ROTTERDAM, the Netherlands—Jumbo Offshore has completed a program involving the transportation and wet storage of a riser caisson for TechnipFMC.
The Fairplayer heavy-lift vessel collected the 120-m long, 1.3-m diameter Caisson from the port of Nigg in northeast Scotland. The rigging arrangement entailed both of the vessels 900-metric-ton cranes employing double slings and five connection points.
Courtesy Jumbo Offshore
Courtesy Jumbo Offshore
Following transportation of the caisson to the offshore location, Jumbo started work on the temporary storage of the caisson (wet storage) on the seafloor.
According to project manager Carol Granneman, “Due to the motions of the waves and the buoyancy of the caisson, the most critical moment was when we lowered the caisson through the splash zone. And then we had to lower it evenly through the water column to avoid excessive stresses in the caisson.”
TechnipFMC performed the calculations for the rigging, while Jumbo worked on the vessel-specific calculations regarding the vessel’s anticipated movement at different phases of the operation.
Once the caisson was in position, the company deployed an ROV to disconnect it, leaving two rigging points in place for TechnipFMC to retrieve for installation at a later date.
