Underwater Stern Tube Seal Repair
Last month a Hydrex diver/technician team carried out underwater stern tube seal repairs on a 148m container vessel in Port of Spain, Trinidad. The ship was suffering from an oil leak, making an on-site 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 the owner an expensive and time-consuming trip to drydock.
Every Hydrex office has a fast response center, equipped with all the latest facilities, equipment and tools. These centers were designed specifically to increase speed of service. The lightweight flexible mobdocks packed in flight containers allowed for a very fast mobilisation and a timely arrival in Trinidad of the Hydrex team.
The diving team first set up a monitoring station. The operation then started with a thorough underwater inspection of the stern tube seal assembly.
After the inspection, the team detached the vessel’s rope guard. Next the divers installed the flexible mobdock around the stern tube seal assembly creating a dry underwater environment so that they could work in drydock-like conditions. The split ring was then disconnected 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 then bonded. This procedure was repeated with the other two damaged seals.
The operation ended with the conducting of pressure tests with positive results, the removal of the flexible mobdock and the reinstallation of the rope guard.
Hydrex has carried out repairs and replacements on all types of seals on-site and underwater, for almost twenty years now. They constantly invest in the research necessary to continue to evolve repair techniques and procedures. Over the years the Hydrex R&D department has improved the flexible mobdock (mobile mini drydock) technique to make it possible for their diver/technicians to perform permanent repairs on seals, thrusters and almost any other part of the underwater vessel without the need for drydock. The latest generation of flexible mobdocks allow us to carry out on-site replacement of virtually any type of stern tube seals very quickly.
Conclusion
Due to the very busy schedule in Port of Spain, the team had to halt the operation on several occasions when one of the vessels next to the container ship left or a new ship arrived. The ship also had to shift several times, making further interruptions necessary. Hydrex divers are however trained to handle these constant changing and challenging circumstances. They worked in shifts to finish the stern tube seal repairs as quickly as possible. Despite the breaks, the operation was carried out without any loss of quality. The owner could sail his vessel free of oil leaks and without having to go to drydock.