Last month, a diver/technician team carried out an underwater stern tube seal replacement on a 180-meter container ship berthed in Algeciras. Seawater had been found in the air chamber and the seal leak alarm had gone off, confirming that the seals where damaged and needed to be replaced.
Using a flexible mobdocks, the team was able to carry out the entire operation on-site and underwater, saving the owner an expensive and time-consuming trip to drydock.
Once the operation was approved, all preparations were handled swiftly, and the required equipment was mobilized to the vessel. Because the ship's mooring location could only be reached via the water, the team made use of a workboat during the operation.
The operation started with the removal of the rope guard. The diver/technicians then took a tail shaft wear-down measurement and cleaned the seal housing components.
The flexible mobdock was installed around the stern tube seal assembly. Communication systems, a camera and lighting were installed inside the habitat, creating a dry underwater environment where the technicians could work in drydock-like conditions.
The intermediate rings were then opened and the liner and rings thoroughly cleaned. A fishing net tangled around the damaged seals was removed by our divers. New seals were then installed and bonded, after which the intermediate rings were closed again.
A successful operation was concluded with leakage tests, the removal of the flexible mobdock and the reinstallation of the rope guard.
Despite changing currents at the location, the team was able to carry out the complete procedure as planned in just under 48 hours.
The fact that Hydrex organized everything from start to finish meant that the owner did not have to make separate arrangements for the underwater part of the repair. The team arrived at the ship with the equipment needed to carry out the seal replacement and complete the operation on-site.
