A riser caisson for Technip FMC has been transported and wet stored by Jumbo Offshore. The project was completed by Jumbo in October, using its heavy-lift vessel Fairplayer to move the caisson with a diameter of 1.3 metres and a length of 120 metres, as reported by Maritime Economy.
Wet storage
Due to the caisson’s great degree of flexibility, the Fairplayer had to carefully adjust the rigging for the operation of picking up the caisson from the port of Nigg in Scotland. Each of Fairplayer’s 900-tonne cranes was equipped with two slings and a total of five connection points for this purpose.
After moving the caisson to the offshore location, Jumbo carried out the project’s wet storage component. Wet storage refers to the temporary placement of offshore parts on the ocean floor, which in the case of this extremely sensitive caisson required cautious procedures.
The offshore scope was the most challenging, says Jumbo’s 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,” he says. “And then we had to lower it evenly through the water column to avoid excessive stresses in the caisson.”
Project Engineering
This project’s preliminary engineering is equally noteworthy. Technip FMC and Jumbo Offshore have a good working relationship and have collaborated on various projects in the past. The two businesses collaborated on the project engineering for this riser caisson. The calculations for the rigging were performed by Technip FMC, and Jumbo worked on calculations particular to the vessel for the movement of the Fairplayer during various operations.
Once on the seafloor, Jumbo disconnected the caisson using an ROV, leaving two rigging points in place so that Technip FMC could pick it up and install it later.
“This job involved the careful handling of fragile offshore equipment. But with our experienced crews and engineering teams, combined with the dual cranes of the Fairplayer, Jumbo Offshore had the technical capabilities and offshore expertise that made this precision operation a success,” notes Granneman. “Technip FMC is a very valued client of ours and we look forward to working with their team in the future.”
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Source: Maritime Economy
