Last month Hydrex diver/technician teams carried out underwater stern tube seal repairs on a 130-meter oil tanker in Rotterdam, the Netherlands, and on a 261-meter container vessel in Singapore. Both vessels were suffering oil leaks, making a fast repair necessary. Using one of the company’s flexible mobdocks the team was able to carry out the entire operation on-site and underwater, saving time and money for the owners.
Every Hydrex office has a fast response centre equipped with all the latest facilities, lightweight equipment and tools. These centers were designed specifically to increase speed of service and allowed us to mobilize diver/technician teams to both vessels within the shortest possible time frame.
When oil was leaking from the stern tube seal assembly of an oil tanker, diver/technicians mobilized from the Hydrex office in Antwerp to the vessel’s location in Rotterdam together with all the needed equipment. After the diving team had set up a monitoring station, the operation started with a thorough underwater inspection of the stern tube seal assembly.
After the inspection, the team removed the rope guard of the vessel. Fishing lines tangled around the liner had caused the oil leak. These were removed by the diver/technicians. The team then installed the flexible mobdock around the stern tube seal assembly creating a dry underwater environment for the divers to work in drydock-like conditions, a necessity for permanent stern tube seal repairs. The split ring was then disconnected and brought to the surface to be cleaned. Next the team removed the three damaged seals one by one and replace them with new ones.
The lightweight flexible mobdocks packed in flight containers allowed for a very fast mobilization and a timely arrival in Singapore of the Hydrex team. A storm was passing over when the team arrived at the container vessel’s location. This meant that the Hydrex divers had to pause the repair on several occasions due to strong currents and could only start the underwater operations again when the weather had improved slightly and full safety could be guaranteed for the divers.
After an underwater inspection revealed that a fishing line had caused the leak, the team removed the rope guard and installed the flexible mobdock around the assembly. After cleaning the entire assembly, the divers removed the first seal and replaced it with a new one which was then bonded. This procedure was repeated with the other two damaged seals.
Both operations ended with the conducting of pressure tests with positive results, the removal of the flexible mobdock and the reinstallation of the rope guard.
Hydrex has carried out repairs and replacements on all types of seals on-site and underwater, for a number of years now. By creating a dry environment underwater, the divers were able to complete the required work on-site. Every day a ship has to go off hire causes a substantial loss of money. The teams therefore worked in shifts to perform the stern tube seal repairs within the shortest possible time frame. This saved both owners the time and money which going to drydock would have entailed.
Press Release, August 10, 2012