Earlier this year, Subsea Global Solution’s office in Busan, Korea completed a biofouling cleaning campaign on one of the largest vessels in the world. A floating liquified natural gas (FLNG) vessel – with an LOA of 488m – it was launched in 2013 and took almost four years to complete, whereby the vessel’s hull had expectedly collected a significant amount of fouling. On several occasions prior to the start of this project, SGS Busan was onsite to assess the degree of fouling and to carry out several tests that would determine the best option for removing the fouling. Strict environmental laws had to be taken into consideration, and the antifouling coating used on the hull precluded divers from using a brush cart system. At the end of the cleaning trials, it was determined that the most effective way to clean the hull would be a combination of hand cleaning (!!!) and the use of specialized cavitation based cleaning equipment.
The SGS project team consisted of 32 members, spanning our various offices. From there, two dive teams were created, including a project manager, supervisor, assistant supervisor, two diver medic technicians, ten divers, and an English-Korean translator. Both teams worked simultaneously on the port and starboard sides of the vessel, working 12 hour shifts from Monday to Friday. Simultaneous operations were a big challenge for the dive teams, and it was essential they were checked daily as the sail away date was closely approaching. Safety measures (following international oil and gas guidelines) were undertaken each day before any diving operations could begin.
Each location of the hull followed the same 3-step procedure, beginning with a pre-inspection that was witnessed by the client and guided by marine biologists, using video and still shots. Sea bay inspections were done via borescope, thus saving time by not opening the grids. Next, cleaning of the area would commence with the use of rubber scrapers and rubber hammers. Finally, a post-inspection was completed to determine the area was free of fouling and any invasive marine species, aided and witnessed by the client and marine biologists. This process continued until all designated areas of the hull were completed.
Over a 5 week period this project involved a total of 12,544 hours of labour, 156 hours of video footage, with 1526 photos captured! This was a large scale, operations heavy, and newsworthy project and all involved were happy with the success achieved at the end of the project!
Subsea Global Solutions remains your GLOBAL RESOURCE to turn to for your underwater maintenance and repair needs. We’re available to provide you with the best solutions – anywhere, at any time, around the world.