Hydrex Underwater Technology has completed the emergency stern tube seal repair to a 134m chemical tanker, after the Antwerp Port Authority demanded an underwater inspection and in-situ repair to the vessel before allowing it to set sail.
The vessel’s crew had carried our temporary repairs to stem the flow of lubricating oil from the stern, but the Port would not let the ship continue on ita schedule before a dive team had inspected the propeller shaft seals.
At the request of the shipowner, Antwerp-based Hydrex mobilised a dive team which found the temporary fix had not completely stopped the oil leak. All four stern tube seals needed to be replaced. However, because the vessel had just been fully loaded, trimming the vessel was not an option so the repair had to be carried out in-situ, underwater.
Hydrex production executive, Dave Bleyenberg, said: “We have been replacing seals underwater for 15 years with our award-winning flexible Mobdock technique. Use of the Mobdock allowed us to devise a repair plan very quickly after the inspection and expedite seal replacement without having to disrupt the owner’s schedule. We also arranged for the new seals and the manufacturer’s engineers to arrive at the Port in time to facilitate the repair in record time.
“We have a large stock of seal repair equipment stored in our fast response units around key maritime hubs, so as soon as the repair requirement was confirmed we mobilised a rapid response dive team and a Hydrex dive support vessel, which deployed to the tanker.”
While the manufacturer’s engineers prepared the seals for installation, the Hydrex team dismantled the vessel’s rope guard and installed the flexible Mobdock around the stern tube seal assembly, creating a dry, underwater environment.
Once in place, diver technicians set about disconnecting the split ring from the shaft for cleaning, after which the damaged seals were removed one-by-one and replaced with new ones. The stern tube seal assemblies were then reinstalled and secured before leak tests were carried out to the satisfaction of the representative of the OEM. Finally, the divers removed the flexible Mobdock and reinstalled the rope guard.