DNV , the Norwegian classification society, had required that the necessary work be done in accordance with class rules for permanent repairs.

Hydrex mobilised a specialised three man diver/welder team from its Belgian headquarters to carry out hull repairs during the vessel's stay in port. A local contractor, part of an international supporting network, was engaged to supply the additional labour, equipment and consumables required.

An inspection in the affected tanks was done and preparations began. The arrival of replacement inserts ordered by the ship's owners was delayed, so the decision was taken to use available steel plates in order not to delay the vessel further. The plates were cut to the correct size whilst a mobdock (mobile mini dry dock - otherwise known as a cofferdam) was pre-fabricated at the facilities of the local contractor. All the equipment required was then mobilised.

Welding and cropping material, ventilation, as well as lighting were installed in the port side tank and the actual repair operation began. The bilge keel, which was over the area that needed to be repaired portside, was cropped and ground as recommended by DNV.

The pre-fabricated mobdock was positioned and secured following the appropriate procedures. Inside the tank, part of the framing was in the way, so this was cropped. The hull plating showed a vertical crack of approx 110mm and the area surrounding this was cut out.

The rolled and prepared insert plate, measuring 300x200x16mm, was then inserted and the standard welding procedure was followed. The frames were then re-installed after completion of the welding operations.

Similar work then had to be done on the starboard side to deal with a similar problem. This time the crack was 180mm. The same procedure was carried out to a successful completion.

After finalising all repairs an underwater inspection was done using CCTV equipment.

Both insert plates and bilge keel modifications were recorded on video and the work was approved. All operations were completed approximately one and a half days after the team arrived. The vessel sailed about two hours after the completion of the job.

MJ Information No: 20015