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Mobdocks

A “mobdock” or “mobile mini dry dock” is based on the cofferdam principle of securing a coffer (or box) to the underwater hull of a ship so as to seal part of it off from the surrounding water. Water is pumped out from the coffer so work can be carried out within this protected ‘dry’ environment.

Hydrex has advanced this concept extensively over the last 30 years, along with the technology to ensure fast, professional and high quality work will be done while the vessel is in situ and even while continuing operations on site, depending on the circumstances. It is now to the point where many kinds of underwater repairs can be done using variations on this principle.

Mobdocks are versatile and highly adaptable. They can be big or small and used for a variety of tasks. This can range from simply sealing off the exterior of the hull while welding work is done inside the vessel or large constructions designed to seal off both ends of a thruster tunnel, with access to the tunnel through a shaft connected to the surface. This spectacular technique enables repair or replacement work to be done on a large thruster (or other part) underwater yet “in the dry”. Hydrex technology ensures that a safe, dry environment is created underwater so that quality work can be carried out within the mobdock in conditions similar to those of being above water.

The latest development in this field is the ‘flexible mobdock’. In the past, a mobdock was always a metal structure designed to make a watertight seal with the hull or other structure and constructed to withstand external water pressure. This was always effective but, of course, requires the construction of mobdocks to do the work. While this usage is still vital for many actions such as insert repairs, we can now do certain repairs using a lightweight flexible mobdock for operations such as stern tube seal replacements and work within the thruster tunnel.

Mobdocks can also be used for anode replacement and a wide variety of repairs on the exterior hull underwater. We are able to adapt to your needs and requirements — both in terms of the work done and the schedules and time scale in which this is needed. It is common for us to provide a 24-hour service with several teams working in shifts around the clock in order to get done to highly professional standards within a very short time period. Our techniques are authorized by all the major classification societies.

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