Hydrex Group

Innovations that help keep the world fleet afloat, operational and out of drydock are extremely valuable to shipowners and managers. Hydrex has been at the forefront of such innovations for more than 50 years.

Pioneers

Fifty years ago, the range of repairs that could be carried out underwater while a ship remained afloat was very limited. Hydrex performed the first large wet-welded repairs on ship hulls in 1976, followed by the first wet-welded rudder repairs in 1977. In 1979, the company introduced the use of cofferdams for underwater hull repair. In 1996, Hydrex carried out the first use of large steel cofferdams for thruster replacement and repair. The list goes on and many of these pioneering innovations have since become standard industry practice.

Innovation Today

Today, Hydrex offers a wide and continuously expanding range of advanced underwater repair procedures that allow ships to remain operational without the cost and downtime associated with drydocking. These services include temporary and permanent hull repairs involving cofferdams, class-approved full-penetration welding and other specialized techniques, stern tube seal repairs, propeller blade repair through cold straightening or cropping using proprietary equipment, rudder repairs, thruster repair, removal and replacement, scrubber pipe repairs, installation of energy-saving devices such as Propeller Boss Cap Fins (PBCF) and custom-engineered solutions for unique technical challenges.

In the Real World

Here are just a few recent examples of Hydrex innovation in action.

A bulk carrier en route from Finland to China ran aground 25 miles east of Frederikshavn in Denmark. The damage included two major holes in the hull, one measuring 5 x 5 meters and the other 8 x 2 meters, along with numerous smaller holes, cracks and indentations. The repair, which was the first of its kind, involved the design, prefabrication and underwater installation of an entire hull section, as well as a very large doubler plate. The ship was able to continue sailing to China under its own power without the need for drydocking.

In Oceania, a dredger operating on a long-term contract had no drydock facilities nearby. The bottom plates were worn and required replacement. Hydrex developed a procedure that made it possible to replace the steel while the dredger remained afloat, despite zero underwater visibility. A cofferdam was installed beneath the hull from inside the vessel, requiring only limited diving operations. Once the cofferdam was secured, the plates could be replaced under dry working conditions, restoring the integrity of the dredger’s hull without taking the vessel off station.

A large ro-ro vessel in Australia required repairs to both stern tube seals. The work was completed in record time by two Hydrex teams. Although the technology itself had already been in use, the logistics, expertise and application of standardized procedures to repair both stern tubes simultaneously represented a highly innovative approach.

A pipe-burying ship moored in the port of Flushing required repairs to a thruster seal box. Complex procedures, including conditioning and cleaning the piston surface and shell plating, installing a new sealing ring and reassembly, were all completed rapidly and with excellent results.

A first-of-its-kind repair was also successfully carried out on a floating wind structure in France. The project required extensive underwater cutting, grinding and multiple passes of full-penetration welding from one side using a backing strip.

Hydrex’s Approach

Innovative standard procedures are often developed in response to unique situations. One example was the first time Hydrex carried out repairs on a bow thruster that required removal and reinstallation. This led to the development of highly effective methods for sealing off the thruster tunnel to create dry working conditions inside, as well as an efficient and innovative system for transporting the thruster between the vessel and the quay.

Hydrex engineers possess the training, technical expertise and practical experience needed to think quickly and solve the unusual challenges that arise during underwater ship repairs. That mindset continues to drive ongoing innovation across the company’s operations.