A 175-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 anchorage in Algeciras.
The divers started the operation by installing a cofferdam on the waterside of the affected plating. Next they removed the bellmouth pipe covering the area on the inside. They could then safely remove the plug and 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 350 x 300 mm. Next they prepared the edges of the hole 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 reinstalled the bellmouth pipe and removed the cofferdam.
Simultaneously one of the pipe reducers in the engine room was replaced by our team. This part of the operation was also approved after ultrasonic testing.
Conclusion
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. These operations follow the Hydrex procedure for welding cracks and inserts in the vessel’s shell plating and they are approved by the major classification societies.
Source: Hydrex
