Seal renewal in New Zealand in tough underwater conditions

In April a Hydrex diver/technician team carried out underwater stern tube seal repairs on a container vessel in Tauranga, New Zealand. The ship was suffering from an oil leak and was not allowed to sail on. Because no drydock was available close by an on-site repair was necessary. Taking advantage of the Hydrex flexible mobdock technique the team was able to carry out the entire operation underwater.

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A leaking seal is always an unpleasant experience for a ship owner. It will force him to go off-hire, costing him time and money. To avoid going to drydock and keep the loss of time to the absolute minimum, Hydrex has developed the technology that enables repairs or replacement of all types of shaft seals to be carried out afloat. The ship can keep its schedule as seal repairs can be performed during cargo operations. By creating a dry underwater working environment around the shaft, work on the seal assembly can be performed in dry conditions. This is done by using our flexible mobdocks which are designed specifically for this type of repairs.  They fit all sizes of seal assembly.

The following case study gives an account of a recent underwater stern tube seal repair performed by Hydrex.

Leaking stern tube seals repaired in New Zealand

Immediately after the operation was confirmed our technical department arranged for a rapid mobilization of a team of Hydrex diver/technicians to the container vessel’s location in New Zealand, together with all the needed equipment.

 The diving team first set up a monitoring station. The operation then started with a thorough underwater inspection of the stern tube seal assembly. The inspection revealed that the rope guard had gone missing and that the bolts were broken off.

 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 team removed the damaged seals one by one and replaced them with new ones.

All parts of the stern tube seal assembly were then reinstalled and secured. Leakage tests were carried out with positive results, after which the divers removed the flexible mobdock.

Fast worldwide response

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 allow for a very fast mobilization and a timely arrival of Hydrex teams on any location around the world. This combined with our network of local support bases provides us with everything we need to successfully complete any job, anytime, anywhere.

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 keeps the down time low.