Beneath the waterline, most modern cruise vessels are equipped with a pair of hydraulically controlled stabilizer fins that can be deployed to counteract the effect of rough sea conditions on the motion of the vessel.

Operating on the high seas always involved a degree of uncertainty. In 2014, a scheduled inspection of a cruise vessel revealed damage to the port stabilizer fin, most likely caused by a collision with underwater debris. To avoid further damage, the decision was made to take the stabilizer out of use until the ship’s next scheduled overhaul.

In March 2017, the vessel entered dry dock in Hamburg, Germany, for a five-day scheduled overhaul. A team of marine engineers from SKF in Hamburg was dispatched to the site to dismount and repair the unit. When the stabilizer was removed from the vessel for inspection, the damage proved more serious than anticipated. Several critical parts of the stabilizer mechanism had been bent or broken, and fixing them was impossible during the dry-dock time available at the scheduled overhaul.

To complete the work in a timely fashion without disturbing the cruise line schedules, SKF and the vessel’s owners decided on a radical course of action: underwater replacement at first opportunity.

At the beginning of November 2017, the vessel arrived for a 58-hour layover in the Canary Islands. Under perfect conditions, clear water and mild water temperatures, a waterproof dome was installed around the fin box inside the hull, allowing divers to safely remove the steel plates that had previously sealed the opening. The new stabilizer fin was then lowered into position, after which the dive team manoeuvred it into the exact placement necessary and mounted it.