Hydrex Performs Underwater Propeller Blade Straightening

MarineLink.com
Tuesday, June 11, 2013
Photo: Hydrex

In April, a diver/technician team performed propeller blade straightening operations on two vessels at anchorage in Kalundborg, Denmark. First the bent blades of a 225–meter bulk carrier were restored. The team then straightened the damaged blades of 158-meter reefer in the same location.

By taking advantage of the in-house developed cold straightening technique, damaged blades can be straightened underwater. This allows a ship to return to commercial operations without the need to drydock. Optimum efficiency of the propellers can be restored by bringing the blades back to their original form.

The Kalundborg Fjord is a perfect location to carry out repair work. Vessels at anchorage there are sheltered from the current. This makes it ideal for underwater repair work to be performed – a nice change for the Hydrex diver/technicians from the sometimes harsh conditions they are faced with during their travels around the world.

With three of the five blades of its propeller severely bent, a bulk carrier needed a fast, on-site solution to restore the propeller’s balance and efficiency. Hydrex diver/technicians are trained to carry out repairs underwater in the shortest possible time frame. A team was therefore rapidly mobilized to the ship’s location in Kalundborg to restore the damaged blades to as close to their original condition as possible.

After the equipment arrived at the vessel’s location the team started the underwater operation with a detailed survey of the affected propeller blades. The inspection revealed that two blades were damaged too severely to be straightened and needed to be cropped, but that a third one could be straightened. The other two blades were unaffected.

The team positioned the straightening machine underwater over the bend in the trailing edge of the first blade. In close communication with the team leader in the monitoring station on-shore, the divers returned the bent blade to its original state. The team then used the information acquired during the inspection to calculate and determine the correct measurements needed to modify the trailing edges of the other propeller blades. Next the divers cropped the blades and ground their edges to give them the correct radius. When the cropping was complete, the Hydrex technicians polished the blades to make sure that any remaining loss of efficiency would be minimal.

After they had completed the repair, the team stayed in Kalundborg until the reefer arrived the next day. Two of the four blades of the propeller of this ship were severely bent. They could both be straightened. The other two blades were not damaged.

After the divers had restored the bent blades with the new generation cold straightening machine, they also performed a hull repair on the same vessel. The team installed a 300 x 300 mm doubler plate over a small hole in the hull plating of the ship. Performing both repairs during one operation saved the owner of the reefer from having to take his vessel to drydock.

www.hydrex.be
 

  • Photo: Hydrex

    Photo: Hydrex

Maritime Reporter July 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Ship Repair & Conversion

Engine Refit for Mersey Pilot Boat

James Troop supplies two new Volvo Penta engines to upgrade Mersey pilot boat   Merseyside-based engine specialist James Troop & Co has secured a deal to supply

BAE Systems Awards Software Contract to SENER

The Spanish company SENER, Ingeniería y Sistemas S.A has closed a contract with U.K.-based BAE Systems PLC for the integration between FORAN CAD/CAM System and

Self-lubricating Bearing Polymer: Safe, Easy to Machine

Many plastics and metallic alloys present machining challenges as some deform and are difficult to maintain exacting tolerances, while others require strict and

Underwater Engineering

Nautilus Awards Contract for Dewatering Plant Design

Nautilus Minerals Inc. has awarded a contract for the design of the Solwara 1 dewatering plant to be used on the company’s production support vessel to the Brisbane

New Load Measurement Solution for Port of Dampier

Strainstall designs and delivers a load measurement solution for the world’s largest floating wharf at Port of Dampier.   Strainstall, part of James Fisher and Sons plc,

IMCA Appoints Faure as President

Bruno Faure, Group Senior Vice President Subsea Projects and Operations at Technip  has taken over the role of President of the International Marine Contractors Association (IMCA),

 
 
Maritime Security Maritime Standards Naval Architecture Pipelines Pod Propulsion Salvage Ship Repair Ship Simulators Shipbuilding / Vessel Construction Winch
rss | archive | history | articles | privacy | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.0812 sec (12 req/sec)