Hydrex was contacted by the owner of a 200-meter bulker which had grounded. The ship had suffered a crack in the bottom plating of one of its ballast water tanks. The company was asked if they could provide an underwater solution that would keep the vessel out of the drydock. A team of their diver/technicians therefore mobilized to Fos-sur-Mer, France, to perform on-site repairs.
On-board and underwater inspection
After arriving on site, the team first performed an on-board and underwater inspection of the damaged area. This revealed a large L-shaped crack in the ballast water tank of cargo hold 2. In close communication with the superintendent of the vessel and the attending class surveyor, it was decided that a 1000 x 820 mm insert would need to be installed.
The new insert plate, and a mobdock measuring 1500 x 1300 mm were fabricated at the Hydrex headquarters in Antwerp. Because the Hydrex fast-response center is fully stocked at all times, both were ready and at the ship’s location very quickly.
Insert repair approved
The divers started the operation by installing the cofferdam on the waterside of the affected plating. To be able to access the crack in the ballast water tank from the inside, the team made an opening in the bilge hopper covering the crack. A frame and support brackets were also removed.
This allowed the diver/technicians to cut away the crack and the surrounding area. The new plate was then inserted into the hull and secured using full penetration welding following the Hydrex class-approved procedure.
The next step was the reinstallation of the frame and support brackets. A new insert was then positioned in the bilge hopper. This plate was welded following the same class-approved procedure.
An independent NDT inspector approved the insert repair and the classification surveyor who was present during the operation gave it a green light.
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Source: Hydrex
