Unplanned downtime right before a trip for a ro-ro ship

Customer

A major carrier of consumer and freight units. This carrier operates a fleet of more than 20 ferries, has more than 30,000 sailings on an annual basis and carries more than 10 million passengers every year.


Challenge

During an inspection of the propulsion box of a ro-ro ship, it was found that the main wheel was loose on the axle. The ship could not continue like this, the challenge was unforeseen and unplanned. This meant that there was enormous time pressure on it; after all, the ship was scheduled to carry passengers.


Solution

It was decided to extract the unit from the ship as a whole. The main wheel was transported together with the main axle to GBS in Schiedam. 24/7 shifts ensured that no time was wasted for this project.


Firstly, the whole axle was cleaned and checked for cracks (at the location of the teeth, the bore and the keyway). Cracks were found in the bore and keyway. It was decided to mill and re-center it. The same procedure was used for the main wash where similar indications of cracks were found to be cut out.


In consultation with Lloyd's Register office, it was decided to repaint the main shaft, to oversize the keyway and to cut away the original bores. This was done in order to re-assemble the whole according to the original shrink-fit. In addition, the teeth of the main wheel have also been ground to get it back in optimal condition.


Result

Thanks to the 24/7 shifts, the knowledge expertise, the advisory role as knowledge partner and the management of the project by GBS, it was realized that the parts could be returned to the ro-ro ship in less than 2 weeks. This allowed the ship to quickly resume its voyage and downtime for the customer was kept to a minimum.