Underwater bow thruster operation in Algeciras

Last month a Hydrex team removed a bow thruster from a 229-meter bulk carrier. Two weeks later the overhauled unit was reinstalled. Both operations were done during stops in Algeciras, Spain and had to be carried out within the tight schedule available to the charterer.

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All the necessary equipment was mobilized from the Hydrex Algeciras fast response center. To keep the impact on the vessel’s schedule to the absolute minimum the divers performed an inspection of the bow thruster unit and tunnel, followed by some preliminary work while the vessel was berthed at a lay-by.

The vessel could then shift and start cargo operations while Hydrex performed the rest of the operation without any hindrance to the loading schedule.

The company’s diver/technicians detached the blades one by one. In the meantime preparations were made in the bow thruster engine room for the removal of the unit so that there would be no ingress of water once it was taken out.

The next step was to secure the gearbox with hoisting equipment. The team then disconnected the unit from the bow thruster engine room and lowered it onto a cradle. This cradle was designed especially for such thruster operations.

Simultaneously the team sealed off the tunnel from the bow thruster room. Once the unit was lifted onto the quay it was prepared for transport to the workshop.

Creating dry underwater conditions

Two weeks after Hydrex removed the thruster unit the team once again mobilized to the vessel. They reinstalled the overhauled unit underwater with the use of the Hydrex flexible mobdocks.

These were used to close off the thruster tunnel once the overhauled bow thruster had been brought inside. This technology has been used during thruster operations for over 20 years now and can be shipped anywhere in the world by plane.

All water was then removed from the tunnel. This created drydock like conditions for the divers despite the vessel staying afloat. The team secured the unit and connected it to the engine room. Once this was done the thruster propeller blades were installed one by one. With the thruster blades in position the ship was ready to sail.

Fulfilling the needs of all parties involved

By performing the thruster removal and reinstallation underwater, Hydrex made it possible for the owner to keep the vessel out of drydock.