Underwater stern tube seal repair avoids drydocking

MAY 30, 2012 — To save time and money for the owners of a 270-meter containership that was leaking oil, a Hydrex diver/technician team recently replaced three stern tube seals, using one of the company’s flexible mobdocks. This enabled the team to carry out the entire operation on-site and underwater during the vessel’s stop in Le Havre.
 
After the divers and all equipment had arrived at the vessel, the Hydrex team leader met up with the vessel’s owner and superintendent while the rest of the diving team set up a workstation to monitor all underwater activities.

Next, all quayside preparations were made for the main activity, which started immediately with the removal of the rope guard. The divers then performed a thorough underwater inspection and shaft weardown readings.This revealed that a rope was tangled around the stern tube seal assembly, causing the oil leak. The rope was removed and the split rings were disconnected and brought to the surface to be cleaned.
 
Next the team installed the flexible Hydrex mobdock, creating a dry working environment around the stern tube seal assembly that allowed the entire assembly to be cleaned.

Subsequently, 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. The divers then reinstalled and secured all parts of the stern tube seal assembly. After a successful leakage test the flexible mobdock was removed and the rope guard repositioned.