MAY 24, 2013 — Hydrex diver/technician teams recently carried out underwater stern tube seal repairs on a 139-meter container vessel in Port Everglades, FL, close to the company’s office in Clearwater. The vessel was suffering from an oil leak, making a fast repair necessary. Using one of the company’s next generation flexible mobdocks (mobile mini dry dock) the team was able to carry out the entire operation on-site and underwater, saving time and money for the owners.

Over the years the Hydrex R&D department has constantly improved the flexible mobdock (mobile mini dry dock) 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 dry dock.

Hydrex says that the latest generation of flexible mobdocks allows it 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 container vessel’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 then removed the rope guard of the vessel as well as the fishing lines tangled around the liner that had caused the oil leak.

Next the team installed the flexible mobdock around the stern tube seal assembly creating a dry underwater environment for the divers to work in drydock-like conditions, a necessity for permanent stern tube seal repairs. After cleaning the entire assembly, the divers disconnected the split ring and brought it to the surface. Next the team removed the three damaged seals one by one and replaced them with new ones. Because the existing running area was completely worn down, the diver/technicians also installed a spacer ring to create a new running area for the seals.

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

By creating a dry environment underwater, the divers were able to rapidly complete the required work on-site. The teams 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.