• Underwater propeller blade cropping in Rio De Janeiro, Brazil

    Underwater propeller blade cropping in Rio De Janeiro, Brazil


    At the end of 2011 Hydrex mobilized a diver/technician team to Rio De Janeiro to carry out a detailed inspection and necessary repair to the damaged port-side propeller blades of a 73-meter supply vessel.

    A wooden beam had fouled the propeller and had damaged three of the four blades. The affected areas of the blades therefore needed to be cropped to restore the propeller’s balance. One blade had been damaged in two different areas, so four pieces needed to be cropped in total.

    To make a full assessment of the damage, the team first performed an underwater inspection. They then used the acquired information to calculate and determine the correct measurements needed to modify the trailing edges of the propeller blades. The diver/technicians then cropped the three blades after which they ground and polished all edges of the cropped areas.

    This kind of repair is carried out to achieve the greatest possible efficiency for the vessel.

    By taking advantage of Hydrex’s in-house developed cold straightening technique, propeller blades that are bent can often be straightened underwater, allowing the ship to return to commercial operations without the need to drydock. In this way optimum efficiency of the propellers can be restored by bringing the blades back close to their original form while the vessel remains afloat.