Underwater blade replacement keeps ship out of drydock

30 Apr 2014
Lifting one of the old thruster blades inside the closed-off thruster tunnel

Lifting one of the old thruster blades inside the closed-off thruster tunnel

In April, underwater repair company Hydrex carried out bow thruster blade replacements on a 270m container ship in Barcelona.

The company reports that a condition of class was issued after cracks were detected in the old blades, forcing the vessel to go off hire until a solution was found. Hydrex was able to perform the underwater operation on site in Barcelona, using the company’s flexible mobdocks.

While the team readied the bow thruster tunnel, the new blades were prepared. The mobdocks were then installed on both sides of the thruster tunnel, and the team evacuated all water from the tunnel, creating a dry working environment.

The diver/technicians removed the first blade of the bow thruster, and brought it to the surface. The replacement blade was lowered into the water, positioned on the bow thruster and bolted on. This procedure was repeated for the other blades. After the blades had been replaced they were put on torque. Leakage tests were carried out successfully and the divers removed the flexible mobdocks.

The ship’s superintendent was present during the procedure, and gave approval. By performing the operation around the clock, on-site and underwater, Hydrex says it enabled the owner to have the condition of class removed without going to drydock.

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