Shell plating repairs in Belgium, the Netherlands and Trinidad
Over the last few months Hydrex teams traveled across the ocean to Port of Spain, Trinidad and just around the corner from the company’s headquarters to Zeebrugge and Amsterdam to perform hull repairs on a car carrier and two tankers. These operations illustrate the diversity of shell plating repairs their diver/technicians are trained for.
Hydrex offers class approved hull repairs combining both underwater cofferdam installation and inside dry welding. Both parts of such an operation are performed by the same team of in-house trained diver/welders working at the highest quality standards.
Insert repairs in Port of Spain
A 164-meter chemical tanker needed to have an insert installed on a damaged section of its bottom plate. A team of diver/technicians therefore mobilized to Port of Spain, Trinidad to perform on-site repairs. The damaged plating was underneath the sounding pipe in one of the ballast tanks. A temporary repair had been performed, but a permanent repair was needed to avoid going to drydock.
After a preliminary inspection, the divers started the insert operation by installing a cofferdam on the waterside of the affected plating. Next, they cleaned the damaged plating and prepared the area for the operation. A round section of the damaged plating with a diameter of 200 mm was then removed. The size of this area was decided in communication with the classification society and the owner. Next the team prepared the edges of the hole for the insert, and positioned the new plate. The insert was then welded following the Hydrex 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 present during the operation. Finally, the team detached the cofferdam from the hull.
Repair in the engine room of a tanker in Amsterdam
A similar operation was performed close to home on a 144-meter oil tanker during its stop in Amsterdam. In this case the damage was situated in the ship’s engine room and an insert measuring 300 by 300 mm was installed. The same standard procedure as in Trinidad was used. The divers have carried out many insert repairs on all types of ships and in all areas of the hull, so they finished the operation very quickly without any delay.
Crack repair in Zeebrugge
For smaller damage such as crack repairs, it is not always necessary to install a new insert. This was the case for a 229-meter car carrier in Zeebrugge, Belgium that had a leak in its forepeak ballast tank. As the Hydrex fast response centers have a large stock of state-of-the-art equipment ready, mobilization for smaller operations like this can be almost immediate.
When the work area was certified gas free, the divers started the operation with an inspection of the damaged area on both sides of the hull. Next the team installed a cofferdam on the outside of the hull. This allowed them to perform work on the crack inside the ballast tank without water ingress.
The team then removed part of the longitudinal frame to gain access to the crack and take the exact measurements. The crack was ground out over its entire length and filled with class approved full penetration welding.
The repair was inspected by an independent inspector and approved by the attending class surveyor. The team concluded the repair by reinstalling the frame and removing the cofferdam.
As a result of this temporary repair the owner of the vessel did not have to go off schedule for an emergency visit to drydock but could make arrangements for a follow up repair at a more convenient time and location.