Hydrex was established in Antwerp in 1974 by Boud Van Rompay (www.boudvanrompay.com) . Since then it has steadily grown into a company the shipping and offshore industry can depend upon whenever there are tough and difficult jobs to do as well as for regular, routine maintenance and repairs. 

Breaking new boundaries: finding solutions to problems

Over the years Hydrex has sent highly trained diving teams to virtually every part of the world. The company has built up an ever-expanding worldwide network of support bases, enabling it to provide fast service at reasonable costs. Besides these support bases, Hydrex has offices in Rotterdam, the Tampa Bay Area (U.S.A.) and Algeciras (Spain).

As skill and confidence is accumulated year by year, the high level of expertise offered by Hydrex is validated by a steadily increasing list of certificates from all the main classification societies. Already in 1992 Hydrex had received a certificate for class-approved permanent underwater crack repairs without condition of class and just recently several big classification societies have awarded Hydrex certificates validating the Hydrex revolutionary flexible mobdock technique to perform permanent underwater stern tube seal repairs.

To be able to provide a large part of  the necessary training in-house and to offer the fastest possible service to customers, the Hydrex premises were expanded in 2001 with a brand new fast response center where an extensive range of state of the art tools and diving support equipment is available at all times for the Hydrex underwater teams.

Hydrex is renowned for bringing drydock-like conditions to the vessel or offshore unit. This helps owners to extend drydock intervals and eliminates the loss of time and production that docking entails. Civil repairs can also be carried out in-situ with the Hydrex large habitat system that was designed and built for the first time in 1991 to carry out repair work on locks.

Development of the cofferdam technology

Hydrex was the first company ever to use a prefabricated cofferdam, introduced as early as 1979 and used to carry out repairs to the m/v Lunar Venture. By 1983 the technology was in use to perform insert repairs in double bottom tanks.  The company has advanced this concept extensively over the last 30 years, along with the technology to ensure that fast, professional and high quality work can be done while the vessel is in-situ and even while continuing normal ship operations. For its innovative work in this field Hydrex won the 2002 Lloyd’s List SMM Award in the category of “Innovation in Naval Shipbuilding and Marine Technology.”

In-situ bow thruster operations

At the time of the award, these techniques were applied mainly to the repair and replacement of bow thrusters. Using steel mobdocks to seal off the thruster tunnel, with an access shaft protruding above the water, work teams accessed the tunnel and from there could work on the thruster in complete safety.

Hydrex has since then developed this technology further using lightweight flexible mobdocks. These modernized mobdocks, which are designed to be easily transported around the world, are used to close off the thruster tunnel on both sides, allowing divers to work in a dry environment around the unit and enabling them to reinstall the propeller blades of an overhauled thruster inside the thruster tunnel after the unit has been secured. They can also replace the blades or seals and perform repair work on a specific part without removing the unit. All of this is accomplished without the need to drydock the vessel.

Underwater stern tube seal repairs

In the summer of 1996, Hydrex divers carried out an underwater face seal replacement on a ro/ro vessel. Face seal replacements had been carried out 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.

At the end of 1999 Hydrex started working on injections with lip type stern tube seals. In 2000 Hydrex carried out tests for wet bonding on lip type seals. These tests showed that wet bonding could only give an 80% result compared with dry bonding. Instead of giving up on replacing lip type seals underwater, Hydrex developed a procedure which avoids wet bonding but still accomplishes successful underwater seal repairs.

In 2002 the flexible mobdock was further developed so that a similar dry underwater working environment could be created around a stern tube seal assembly to facilitate repair work on the assembly and enable the replacement of damaged seals in-situ. This technique has since been refined and used on numerous stern tube seal repairs around the world.

In the last few years Hydrex divers have used the flexible mobdock technique for both bow thruster and stern tube seal repairs on numerous occasions during operations around the world. The company’s success with these types of repairs earned it the prestigious Ship Repair and Conversion Award at Lloyd’s List Global Awards 2009.

Permanent underwater rudder repairs

A new repair technique allows Hydrex to also perform permanent repairs on any type of rudder while the vessel remains at anchorage and cargo operations can continue. Permanent underwater rudder repairs were hitherto not possible and ships had to drydock in cases where a major defect was found. The newly designed equipment can be mobilized very rapidly using Hydrex special flight containers for worldwide delivery of this new service.

Permanent underwater repairs to all types of propellers

In its quest to provide cost effective services to customers, Hydrex developed procedures to address different kinds of damage to propellers. This research led to the design of the Hydrex cold straightening machine, which was first used in 2002. By taking advantage of this technique damaged blades can be straightened underwater, allowing the ship to return to commercial operations without the need to drydock. A new model of the straightening machine was recently put into practice. It is compatible with the existing model and is used to restore more severely bent propeller blades to their original condition.

If the damage is beyond repair, the damaged blade will be cropped, along with a corresponding section of the opposite blade, by our team to restore the hydrodynamic balance. This kind of repair is carried out with the propeller blade cutting equipment developed by the Hydrex research department in 1985.

The Hydrex R&D department has also developed a repair system that allows Hydrex to perform permanent underwater repairs to every type of propeller in dry conditions. All kinds of repair or maintenance work can be carried out to propellers, twin propellers, variable pitch propellers, azipod and collapsible thrusters.

This is especially important news for supply vessels, navy ships or any vessel under contract or on a location far away from available drydock possibilities. Staying on hire for underwater repairs will save precious time and money.

This new repair system can be transported by air transport to any location around the world from the Hydrex fast response centers within a very short time frame. It can be assembled very quickly (12 hours) on-site.

With the implementation of this technique our diver/technicians can now perform permanent repairs to all parts of the underwater ship propulsion system in drydock-like conditions.

Hydrex continues to invest in the research necessary to keep evolving the available repair techniques along with continual training and development of its engineers and diver/technicians. This is done to offer customers the most efficient solution, whether the required services involve the inspection of a vessel’s external condition and any required maintenance work or highly technical major repairs and replacements of a ship’s external underwater equipment and machinery. 

Trip down memory lane