Air-Injection System Reduces Noise, Vibration

When Zuiderdam, the first Vista-class ship, entered service, it quickly became evident that the aft part of the main restaurant had higher-than-usual noise and vibration levels. On all Holland America ships the aft section of the main restaurant is located above the propellers, but on Vista-class ships the main restaurant was located three decks lower and therefore is closer to the propellers.

Fincantieri engaged Danish consulting company Odegaard & Danneskiold-Samsoe to work with the shipyard’s noise and vibration department to develop a solution. They hit on the idea of installing an air-injection system that would create a cushion of air bubbles between the propellers and the hull to absorb some of the noise frequencies that would otherwise be transferred directly to the hull. A similar system had been installed on private yachts before, but the technology had never been tried on a large cruise vessel.

A similar system had been installed on private yachts before, but the technology had never been tried on a large cruise vessel.

Oosterdam was under construction at the time and a temporary compressed air system was installed approximately eight meters in front of its propellers. During Oosterdam’s sea trials the system was tested under various conditions and worked very well, reducing noise levels dramatically. A permanent system was installed on Oosterdam consisting of a compressed air piping system connected to two compressed-air blowers located in the Azipod housings.

The power-management system engages the blowers automatically when propulsion power reaches a predetermined level and turns the system off when power is reduced. The air-injection system is simple, requires little maintenance and uses minimal power.

The system was installed on all of the Vista-class vessels and, with Eurodam, will be installed on all upcoming Signature-class ships.