One of our diver/technician teams carried out an underwater stern tube seal repair on a 140-meter general cargo ship at anchorage in Port of Spain, Trinidad. 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 swiftly 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 on a workboat 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.

This revealed that a rope had become entangled around the stern tube seal causing the oil leak. Our divers removed the rope during the inspection. They then cleaned the assembly and installed the flexible mobdock. By doing this they created a dry underwater environment so that they could work in drydock-like conditions.

The split ring was then removed 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 bonded. 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.

Additional repair with same team

The tests at the end of the stern tube seal repair had revealed a leak on one of the blade seals of the propeller which the owners asked us to repair immediately. A team of four of our diver/technicians therefore stayed on standby until the spare parts for the propeller blade had arrived.

During this time the ship had shifted to a layby-berth. The blade was trimmed above the surface and a pontoon and equipment was set up. This allowed the team to start the blade seal renewal as soon as the spare parts arrived.

After the blade was lifted and the seal renewed, the bolts were put on torque and secured. A follow-up leakage test confirmed that the work had been successful, finalizing the operation.

Changing circumstances, constant service

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

Because Hydrex organized everything from start to finish, the owner did not have to worry about making any arrangements for the repair.

Combining the initial operation with an additional repair is a good example of the flexibility we offer to our customers. Our teams know how to handle unexpected circumstances and adapt to changing situations.

After all damaged seals had been successfully replaced, the owner could sail his vessel to its next stop free of oil leaks.