An emergency call came in on a late Friday afternoon to carry out a permanent insert repair on board a 145-meter chemical tanker that had suffered a crack in its port side grey water tank. The work was carried out during the vessel’s stop in Amsterdam.
After arriving on site, our team of diver/technicians started with an on-board and underwater inspection of the damaged area. This revealed that the crack was 480 mm long and had split in two at the port side end. In close communication with the superintendent of the vessel and the attending class surveyor, it was decided that a 700 x 300 mm insert would need to be installed.
Our team then used a special frame to take the measurements required to fabricate a mobdock that would perfectly fit the rounded shape of the hull. The steel mobdock and the new insert plate were then fabricated at the Hydrex headquarters in Antwerp. Because our fast-response center is fully stocked at all times, both were ready and at the ship’s location very quickly.
After the mobdock had been installed, the frame above the crack was removed by the team. This allowed our diver/technicians to cut away the crack and the surrounding area. The new insert plate was then positioned and welded with full penetration weld following our class-approved procedure.
An independent NDT inspector approved the insert repair and the classification surveyor who was present during the operation gave his green light. The frame covering the affected area was then reinstalled, concluding the operation.
By removing the large crack and installing a new insert this area of the ship will not require further repairs during her next drydocking. The vessel could sail on time as the repair was carried out well within the stipulated time frame.