We have developed a flexible mobdock repair method that enables the underwater replacement of all types and sizes of shaft seals. This technology has been successfully used for many years. It allows ship owners to keep their vessel sailing, saving precious time and money.

Damaged stern tube seals will result in increasing amounts of oil leaking or water ingress as the damage worsens. By replacing the seals when the damage is first discovered, we keep the downtime low. The ship can keep its schedule because seal repairs can be performed during cargo operations. We do this by creating a dry underwater working environment around the shaft.

It is not always straightforward to replace seals, because there can be considerable variation in the configurations of the stern tube itself. There can also be complications with the liners, which can be worn down and show grooves. All this is routinely handled by our teams on the jobs.

All shaft seal repairs we offer are performed in cooperation with the OEM. This allows us to supply the correct OEM seals and handle all type of seals from all manufacturers.

In this article you can find a short summary of a selection of recent seal repairs our teams have performed.

Leaking seal assembly fixed underwater in Antwerp

One of our diver/technician teams carried out an underwater stern tube seal repair on a 300-meter container vessel berthed in Antwerp. The ship was leaking oil, making an immediate repair necessary. Using a Hydrex flexible mobdock 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 confirmed all preparations were handled quickly and the lightweight equipment was mobilized immediately from our headquarters in Antwerp. After arriving on-site, the diving team first set up a monitoring station next to the vessel. The operation then started with the removal of the rope guard and a thorough underwater inspection of the stern tube seal assembly.

After the inspection the divers cleaned the assembly and installed the flexible mobdock. The split ring was then removed and brought to the surface to be cleaned. Next the divers removed the first seal and replaced it with a new one which was bonded. This was done in cooperation with the supervising OEM technician.  The procedure was repeated with the other seals.

A successful operation was concluded with leakage tests, the removal of the flexible mobdock and the reinstallation of the rope guard.

Stern tube seal repairs in Australia

We mobilized our diver/technician teams to a 180-meter ro-ro vessel in Port Burnie, Tasmania to carry out stern tube seal replacements.

Despite the remote location of the ro-ro vessel, our technical department was able to make all practical logistic arrangements and organize a mobilization of the equipment very swiftly. In the recent past we have carried out several operations in Australia, including repairs on this ro-ro ship’s sister vessel.

Double repair on pipe laying vessel in Rotterdam

Our diver/technicians replaced the seals of both stern tube assemblies of a pipe laying vessel berthed in Rotterdam.

A team traveled to the vessel’s location on one of our workboats. These workboats are fully equipped as dive support stations with hydraulic cranes, winches, nautical and communication equipment, and a dive control room. They are stationed in Rotterdam and Antwerp which allows for a fast mobilization throughout both ports.

Working together with the OEM allowed Hydrex to provide the customer with original spare parts which guarantees the best quality material. A technician of the seal manufacturer was also present during the operation.

By organizing everything from start to finish the owner did not have to worry about making any arrangements for the repair. After the seals had been successfully replaced he was able to sail his vessel to its next stop free of oil leaks