Hydrex has revealed that their team of divers/technicians recently performed a propeller blade cropping on a 190-meter container bulker berthed in Hamburg to restore the propeller’s balance and restore efficiency. One of the four blades of the bulker had lost two parts of its tip.
Usually an in-house developed cold straightening technique is used by Hydrex. This procedure enables the technicians to straighten damaged blades in-water, allowing commercial operations to continue without the need to drydock. However, for this particular ship example, cropping was the only option as the type of damage to the propeller blade did not allow cold straightening. This kind of repair is carried out with the propeller blade cutting equipment developed by the Hydrex research department.
Hydrex say that in cases such as this one, where there is an even number of blades an identical piece will be cropped from the opposite blade to restore the hydrodynamic balance of the propeller. By doing so, the best possible efficiency is obtained.
When the cropping was complete, the Hydrex technicians buffed the blades to make sure that any remaining loss of efficiency would be minimal.
In the case of this ship, the repair took less than a day.
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