Underwater repair allows vessel to continue its schedule.
When the fore as well as the aft stern tube seals of a 247-meter tanker were leaking, the vessel was not given permission to enter any ports. Unloading the vessel at sea and going to drydock seemed the only option for the vessel, until Hydrex sent a diver/technician team with one of the company’s flexible mobdocks to the ship’s location in Port Gentil, Gabon, to replace both sets of stern tube seals on-site.
The team loaded the necessary equipment on a barge on which they set up a work station to monitor all underwater activities. The barge then sailed to the tanker and the Hydrex team leader met up with the vessel’s owner and superintendent. The rest of the diving team made all remaining preparations for the main activity, which started, immediately after the meeting, with the removal of the rope guard. This was followed by a thorough underwater inspection and shaft wear down readings.
While the Hydrex flexible mobdock was installed around the stern tube seal assembly to create a dry underwater environment around the assembly, Hydrex technicians replaced the fore stern tube seals which are located on the inside. Next the team started the work on the aft seals. This was done inside the flexible mobdock in drydock-like conditions, which are essential for stern tube seal repairs. The diver/technicians cleaned the entire assembly before they removed the damaged seals one by one and replaced them with new ones. Like the fore seals, these were prepared onshore by the attending Aegir-Marine specialist.
All parts of the stern tube seal assembly were then reinstalled and secured. After a successful leakage test the team removed the flexible mobdock and repositioned the rope guard.
By sending the Hydrex flexible mobdocks in our special fly away cases together with all equipment, fast response to any emergency call like this is guaranteed to locations around the world from the various Hydrex offices. Every day a ship has to go off hire causes a substantial loss of money, and having to arrange the vessel to be unloaded at sea would have been an organizational and financial disaster for the owner. By performing both the repair on-site and underwater, Hydrex made sure that the vessel could keep to its sailing schedule and did not have to go into drydock.