Fast Underwater Stern Tube Seal Replacement with New Generation Mobdock

Last month a Hydrex diver/technician team carried out underwater stern tube seal repairs on a 190-meter bulker vessel in Zeebrugge, not far from headquarters in Antwerp. The repair was performed in icy weather conditions.

The vessel 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 owners.

Hydrex continues to invest in the research necessary to keep evolving 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, rudders and almost any other part of the underwater vessel without going to drydock.

The latest generation of flexible mobdocks allows Hydrex to carry out the replacement of virtually any type of stern tube seals very quickly on-site.

These flexible mobdocks are stored at the fast response centers. Designed specifically to increase speed of service, these centers are equipped with all the latest facilities, lightweight equipment and tools. This allowed us to mobilize a team together with all the needed equipment to the bulker’s location within the shortest possible time frame.

After the diving team had set up a monitoring station, the operation started with a thorough underwater inspection of the stern tube seal assembly. The divers discovered that the rope guard was missing.

The team then installed the flexible mobdock around the stern tube seal assembly creating a dry underwater environment, a necessity for permanent stern tube seal repairs. Next the team removed the damaged seals one by one and replaced them with new ones.

The operation ended with the conducting of a pressure test with positive results and the removal of the flexible mobdock.

By creating a dry environment underwater, the divers were able to rapidly complete the required work on-site. Every day a ship has to go off-hire causes a substantial loss of money. The teams therefore worked in shifts to perform the stern tube seal repairs within the shortest possible time frame. The in-situ repair saved the owner the time and money which going to drydock would have entailed.