Correcting vibration issues with no downtime

Spanish ferry operator Naviera Armas runs a 24/7 passenger service between mainland Spain and the Canary Islands. As customers frequently plan their trips weeks or months in advance, unplanned downtime would have costly consequences for the company. So, when passengers on board one of its roll-on/roll-off ferries started to complain about excessive vibrations, Naviera Armas needed to act fast. The ferry operator called upon SKF Marine to investigate the cause of the issues.

Assessing the situation

A service engineer from SKF Machine Support was deployed to perform a general inspection of the vessel. Using an SKF Microlog handheld condition monitoring device, he measured the vibration levels of various components along the main shaft line, including the engines, gearboxes, and shaft generators. This initial assessment revealed that the mounts below the ferry’s four main engines had worn out and the isolators had insufficient clearance, causing excessive vibrations on the ship’s hull. The engineer also reported engine damage as a result of the vibrations.

Fixing the faults without delay

After the initial assessment of the machine condition, SKF quickly started on the work.  To avoid disruption to service, repairs had to be carried out while the vessel was in operation. And, as each of the four main engines has 13 isolators, there was much work to be done. With three engines running during the maintenance work, conditions in the engine room were hot and noisy. Working around the clock, a team of four engineers repaired the damaged engines, adjusted the mounts, and corrected shaft and shaft generator alignment to reduce vibrations to a tolerable level. In addition, the generator mounts were replaced with adjustable SKF Vibracon chocks to simplify future adjustments.

Thanks to the engineers’ quick response times and hard work, the initial repairs were completed in just four days and with no downtime—meaning Naviera Armas could get its passengers to their destinations without disruption. Now that the issues are fixed, the next step is to replace the engine mounts. SKF will perform this task while the vessel is docked during its next scheduled maintenance period.