Underwater Stern Repair Avoids Drydock

In May, Hydrex diver/technician teams carried out underwater stern tube seal repairs on a 292-meter, 50,644 grt container vessel in Singapore. The ship was suffering from an oil leak, making a fast repair necessary. Using one of the company’s flexible mobdocks the team was able to carry out the entire operation on-site and underwater, saving time and money for the owner.

Every Hydrex office has a fast response center equipped with all the latest facilities, equipment and tools. These centers were designed specifically to increase speed of service. The lightweight flexible mobdocks packed in flight containers allowed for a very fast mobilization and a timely arrival in Singapore of the Hydrex team.

After the diving team had set up a monitoring station, the operation started with a thorough underwater inspection of the stern tube seal assembly. This revealed that a fishing line had caused the leak.

After the inspection, the team detached the rope guard of the vessel. The fishing lines entangled around the liner were then removed. The divers then installed the flexible mobdock around the stern tube seal assembly creating a dry underwater environment for the divers to work in drydock-like conditions. The split ring was then disconnected and brought to the surface to be cleaned. After cleaning the entire assembly, 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 operation ended with the conducting of pressure tests with positive results, the removal of the flexible mobdock and the reinstallation of the rope guard.

Hydrex has carried out repairs and replacements on all types of seals on-site and underwater, for a number of years now. Hydrex constantly invests in the research necessary to continue to evolve repair techniques and procedures. Over the years the Hydrex R&D department has constantly improved the flexible mobdock (mobile mini drydock) technique to make it possible for Hydrex diver/technicians to perform permanent repairs on seals, thrusters and almost any other part of the underwater vessel without the vessel needing to go to drydock. The latest generation of flexible mobdocks allows Hydrex to carry out on-site replacement of virtually any type of stern tube seals very quickly.

Going off hire causes a substantial loss of money for the owner. The teams therefore worked in shifts to perform the stern tube seal repairs within the shortest possible time frame. This allowed the owner to let the ship continue its schedule without unnecessary delay, saving him precious time and money.

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