Underwater Stern Tube Seal Repair Minimized Oil Leakage


Recently the Hydrex diver/technicians performed stern tube seal repairs underwater in Antwerp and Tasmania, says a press release published on their website.

Stern tube seal damage

Damaged stern tube seals will cause an increasing amount of oil leaking or water ingress as the damage worsens. 

By replacing the seals when the damage is first discovered, Hydrex can keep the down time low. 

The ship can keep its schedule because seal repairs can be performed during cargo operations. This is done by creating a dry underwater working environment around the shaft.

Is replacing seals a straightforward job?

It is not always straightforward to replace seals, because there can be quite a bit of 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 Hydrex teams on the jobs. All Hydrex shaft seal repairs are performed in cooperation with the OEM.

Example of a stern tube seal repair 

Below is an example of a stern tube seal repair one of the Hydrex teams performed.

Leaking seal assembly fixed underwater in Antwerp

A Hydrex team carried out an underwater stern tube seal repair on a 300-meter container vessel berthed in Antwerp. 

The ship was suffering from an oil leak, 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 the company’s headquarters in Antwerp. 

Work progress 

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. 

Seal replacement

Next the divers removed the first seal and replaced it with a new one which was bonded. The procedure was repeated with the other seals.

Leakage tests

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

No need to plan for the repair 

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 could sail his vessel to its next stop free of oil leaks.

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Source: Hydrex


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