• Rope guard removal during stern tube seal repair
    Rope guard removal during stern tube seal repair
  • Hydrex flexible mobdocks allow underwater repairs and all types of seals
    Hydrex flexible mobdocks allow underwater repairs and all types of seals
  • All welding work is carried out by experienced divers
    All welding work is carried out by experienced divers

Seal repair and replacement

Hydrex has carried out repairs and replacements on all types of seals underwater and in-situ for a number of years now. Hydrex has developed the technology that enables seal replacements to be done on site and underwater. By creating a dry underwater working environment around a seal assembly, repair work on the assembly is facilitated. It enables the replacement of damaged seals on site. Prior to this technology it was usually necessary to go into drydock for this kind of operation, along with all the attendant loss of time and money.

In the summer of 1996, Hydrex divers carried out an underwater face seal replacement on a Ro-Ro vessel. Face seal replacements had previously been practiced by our divers in the Antwerp workshop, but now they were able to actually perform this task while in the water. Since then Hydrex has constantly worked to advance the techniques used for stern tube seal repairs.

In 1998 our divers completed a seal repair training course led by John Crane Marine, who also worked together with Hydrex in the testing of new developments. At the end of 1999 we successfully started working on injections with lip type stern tube seals.

The next year Blohm & Voss gave our divers a training course to perform operations on their Simplex seals and in the same year we started doing tests for wet bonding on lip type seals. These tests showed us that wet bonding could only give us an 80% result compared with dry bonding. Instead of giving up on replacing lip type seals underwater, we started working on a method to avoid wet bonding and still do the seal repairs underwater. This led to the development of our unique flexible mobdock technique in 2002, which allowed us to create a dry working environment underwater and took us an important step forward. For the first time it became possible to entirely replace stern tube seals under water.

Since then Hydrex has continued to develop the mobdock technique to adapt it to all possible situations.

The technique has won one of the prestigious Lloyd’s List Awards on two occasions. Several major classification societies have also awarded Hydrex certificates that accept the Hydrex revolutionary flexible mobdock technique to perform permanent underwater seal repairs.

An overview of some of the more important seal repairs carried out by Hydrex can be found on this page.

Please click on this link to read what our customers have to say about Hydrex.

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