Hydrex completed the critical underwater Stern Tube repair in just under 48 hours, avoiding the need for a costly drydock visit
Belgium-based underwater ship repair specialist Hydrex has completed an underwater stern tube seal replacement on a 180-metre container ship in Algeciras, allowing the vessel to remain afloat and avoid a costly drydock visit.
The repair was required after seawater was detected in the vessel’s air chamber and a seal leak alarm was triggered, confirming that the stern tube seals had been damaged and needed to be replaced.
Following approval of the repair, Hydrex rapidly mobilised its diver/technician team and the equipment required to carry out the operation directly at the vessel’s berth. As the ship’s mooring location could only be accessed from the water, a workboat was used to support the operation.
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.
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.
By managing the mobilisation, equipment, diving operations and repair process as a single service, Hydrex enabled the vessel owner to complete the stern tube seal replacement without arranging a separate underwater repair operation or undertaking an additional voyage to drydock.
The project demonstrates how flexible underwater habitats can provide shipowners with an alternative to conventional drydock repairs, reducing both operational disruption and the time associated with taking a vessel out of service.
