Underwater stern tube seal repairs in Australia and Colombia
Recently Hydrex mobilized diver/technician teams to vessels in Colombia and Australia to carry out stern tube seal replacements. In Cartagena the repair was carried out on a 294-meter tanker, and in Burnie, Tasmania, on a 195-meter roro vessel.
The company have developed a flexible mobdock repair method that enables the underwater replacement of all types and sizes of shaft seals. This technology has been successfully used for many years. It allows ship owners to keep their vessel sailing, saving precious time and money.
Damaged stern tube seals will result in increasing amounts of oil leaking or water ingress as the damage worsens. By replacing the seals when the damage is first discovered, Hydrex keeps the downtime low. The ship can keep its schedule because seal repairs can be performed during cargo operations. They do this by creating a dry underwater working environment around the shaft.
It is not always straightforward to replace seals, because there can be considerable 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 the teams on the jobs.
All shaft seal repairs are performed in cooperation with the OEM. This allows Hydrex to supply the correct OEM seals and handle all types of seals from all manufacturers.
Remote location no problem for Hydrex
Despite the remote location of both vessels, the technical department was able to make all practical logistic arrangements and organize the mobilization of the equipment very swiftly. In the recent past Hydrex has carried out several other seal operations in Australia, as well as Trinidad and Tobago.
The same procedure was followed for both repairs: After arriving on-site, the diving team first set up a monitoring station next to the vessel. The operation then started with a thorough underwater inspection of the stern tube seal assembly.
Next the divers cleaned the assembly and installed the flexible mobdock, thereby 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 was done in cooperation with the supervising OEM technician. 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.