Hydrex Performs Underwater Stern Tube Seal Repair

In August, the stern tube seals of a 67-meter, 2223 grt anchor handling vessel were replaced in Port Gentil by a Hydrex team of diver/technicians. The old seals were damaged and a fast repair was therefore necessary. The team carried out the entire operation on-site and underwater with one of the company’s flexible mobdocks. This saved the owner an unscheduled trip to drydock.

All Hydrex offices have fast response centers. These are equipped with the latest facilities, equipment and tools to increase speed of service. Special flight containers are used to transport the lightweight flexible mobdocks. This allowed for a very fast mobilization and a timely arrival of the Hydrex team in Port Gentil.

First the diving team set up a monitoring station. Next the actual operation started with a thorough underwater inspection of the stern tube seal assembly. This revealed that a fishing net had become tangled around the assembly.

The team detached the rope guard of the vessel and removed the fishing net from the liner. The divers then set-up the flexible mobdock around the stern tube seal assembly thus creating a dry underwater environment. It allows the divers to perform any necessary work on the assembly in conditions similar to a drydock. This is essential because stern tube seal repairs cannot be carried out in the wet. Next the team disconnected the split ring and brought it to the surface. After cleaning the entire assembly, the divers removed the first stern tube seal. A new seal was then installed and bonded. The other three damaged seals were then replaced following the same procedure.

Pressure tests were then carried out with positive results after which the flexible mobdock could be removed and the rope guard reinstalled. This wrapped up the operation.

For almost twenty years Hydrex has carried out repairs and replacements on stern tube seals on-site and underwater. Hydrex said it constantly invests in the research necessary to keep developing new repair techniques and evolving existing procedures. This has made it possible for Hydrex divers to perform permanent repairs to all parts of the underwater ship propulsion system in drydock-like conditions.

For many years Hydrex's technical department has been dealing with all kinds of circumstances in locations around the world. This enabled Hydrex's team in Port Gentil to perform the seal repair under the strictest safety regulations, to the highest quality standards and without any delay.