Putting it straight
Putting it straight
The Paglia Orba ferry from Corsica Linea SAS had an unfortunate accident while entering Bastia port in January 2021. The damage forced the ferry to be taken out of service and to drydock at CMR Tunisia Ship Repairs.
The damage to the propeller shaft was very evident and pretty severe, with the intermediate shaft also being bent.
“Corsica Linea contacted MarineShaft, and we offered a complete repair of the propeller shaft and intermediate shaft,” says Hanne Magnussen, Marketing Manager for MarineShaft A/S. “They trusted our repair history and sent both shafts to our workshop in Denmark by truck.”
Once the propeller shaft arrived at the workshop it was inspected and found that the almost 19m long propeller shaft had a deflection of 7.7 degrees and was almost 250mm off centre at the worst area.
Extensive non-destructive tests were carried out by a third party and supervised by a BV surveyor. “The tests confirmed that the material was intact, and we could carry on with our repair procedure for class approval,” explains Magnussen. “We do a thorough calculation before any straightening job. Our purpose-built hydraulic presses are our ‘horsepower’. We have several hydraulic presses, and our most extensive press can press with 6,000 tonnes force and straighten shafts/rudder stocks up to 1.5m in diameter. It takes years of training for our engineers to be able to accomplish this.”
The Paglia Orba job
The repair work involved the cold straightening and repair of an intermediate shaft of Ø390 x 7,450 mm and the cold straightening and repair of a propeller shaft Ø1,058/421 x 18,875mm, including twin tube. The propeller shaft bearing journals were repaired by laser cladding.
“After the cold straightening, repair, and assembling, we carried out a pressure test on the twin tube, which was witnessed by the maker Kongsberg,” explains Magnussen.
“The job done by the MarineShaft team is amazing,” says Bruno Rogier, Superintendent at Corsica Linea SAS. “I was really impressed by your knowledge, technicity, and trusted you to restore the shaft. A lot of sceptical people told me you are wrong by attempting to repair instead of manufacturing a new one, but I am now happy to prove them wrong.”