Class-approved underwater shell-plating replacement in Algeciras

December 5 2022

A 135-meter tanker suffered cavitation damage to the inside shell-plating of one of its ballast water tanks. Hydrex mobilized a team to Algeciras to perform a permanent insert repair that would prevent an unscheduled drydock visit for the vessel.

The team sailed with a workboat and all necessary equipment to the ship which lay at anchor in Algeciras.

After arriving on site, the team of diver/technicians started with an on-board and underwater inspection of the damaged area. This revealed that the crack was 150 mm long. In close communication with the superintendent of the vessel and the attending class surveyor, it was decided that a 300 x 300 mm insert would need to be installed. The divers started the operation by removing a part of the bilge keel. This was required to install the customized cofferdam on the waterside of the affected plating. Because it needed to fit the rounded shape of the hull perfectly it was tailor-made at the Hydrex  fast response center. Next they removed the cement box which had been installed as a temporary solution. The damaged plating was then cleaned and prepared for the operation. As agreed with the classification society, the team then cut away an area measuring 300 x 300 mm. Next they prepared the edges of the opening for the insert and positioned the new plate. The insert was then welded following the Hydrex class-approved procedure for insert plates, using a full penetration weld. An independent inspector carried out ultrasonic testing and the repair was approved by the classification surveyor who was present during the operation. The team then removed the cofferdam.

A fast, permanent solution

By removing the cracked section of plating and installing a new insert this area of the ship will not require further repairs during its next drydocking. The vessel could sail on time as the repair was carried out well within the stipulated time frame. The operation in Algeciras was performed to the highest quality standards by in-house trained diver/welders. Hydrex has a wide range of cofferdams at our disposal as well as certified plating which we can mobilize immediately to any location around the world. Repairs like this can be carried out above or below water, according to the circumstances, with external cofferdams. Normal commercial activities can therefore continue without disruption.