Hydrex straightens bulker’s bent propeller blade

When a 190-meter bulker bent a propeller blade in early January, Antwerp, Belgium, based underwater repair specialist Hydrex was contacted, and rapidly mobilized a diver/technician team to Rotterdam to perform a detailed underwater inspection and repair of the damage.

Later that month a team carried out a similar operation in the same port on a 230-meter vessel.

The team found that one of the propeller blade tips of the first vessel was deformed over an angle of 30° and proposed a straightening with the Hydrex in-house developed cold straightening machine. The inspection of the second vessel revealed that all four blades were bent over angles ranging from only 3° to 35°.

Hydrex carried out both operations after the vessels had been trimmed. By taking advantage of the Hydrex cold straightening technique the teams were able to straighten the bent blades on-site. This allowed the ships to return to commercial operations without the need to drydock.

Propeller blades that may have suffered from an impact will have a performance below average. Should this be the case, then the engine will have a higher work load, resulting in increased fuel consumption and added stress. By bringing the blades back close to their original form Hydrex can restore a propeller’s efficiency and balance.

The cold straightening machine has been in use for quite some time now, but Hydrex says its research department is constantly looking into ways to enhance the technique. A new model of the straightening machine was recently put into service. It is compatible with the existing model and is used to restore more severely bent propeller blades.

March 29, 2012