As cruise operators face growing scrutiny around emissions and Underwater radiated noise (or noise performance), propulsion is increasingly being judged on more than efficiency alone. Advances in thruster design, hybrid power systems and fuel technologies show how quieter, cleaner operations can improve both passenger comfort and minimize underwater noise radiation which helps to protect marine life and strengthens long-term access to sensitive marine area’s.
For a passenger, some of the most defining moments of their voyage occur when the ship is operating at its lowest speeds.
Early morning arrivals and extended maneuvering in portage phases where comfort is shaped less by headline amenities and more by how the vessel behaves mechanically. Noise, vibration, and the subtle movements created by propulsion can become immediately noticeable. When they are well controlled, they largely disappear from passenger awareness.
These outcomes are determined by propulsion and power system decisions that are rarely visible to guests. Both thruster design and power system architecture, all influence how a ship performs during its most sensitive operational phases. While these systems are often discussed in terms of efficiency, compliance or lifecycle cost, they also play a direct role in passenger comfort and in how cruise ships are received by port communities.
This reflects a broader shift in how propulsion performance is assessed. The focus is moving away from only optimizing for peak output and towards optimization and refinement throughout the power chain. Both clean exhaust and Lower noise and vibration, are becoming the benchmarks against which modern cruise vessels are judged.
Maneuvering is where comfort is tested
Cruise ships typically arrive in port early in the morning, often between six and seven o’clock. At that time, many passengers are still asleep. It is well known that the use of Tunnel Thrusters that are used to dock the ship can be disturbing for passengers particularly those in forward cabins or spaces close to the hull. Unstable water flow can generate turbulence, pressure fluctuations, and associated noise and vibration are felt throughout the vessel. This is why there is a high focus to mitigate this source of noise.
Technologies such as ELOGrid™ by Wärtsilä address this challenge directly. By stabilizing the flow into tunnel thrusters, ELOGrid™ has three distinct positive effects. It improves hydrodynamic efficiency which results in better hull efficiency and more available side thrust but it also reduces noise and vibration during maneuvering. This translates into lower energy use, better control of the ship and quieter arrivals and departures, with reduced vibration transmitted into cabins, dining rooms and public spaces
The same characteristics also matter beyond the vessel. Reduced underwater noise is increasingly relevant in ports and coastal regions where environmental impact is under closer scrutiny. Underwater noise from cruise vessels is primarily driven by propeller cavitation, which can account for up to 85% of radiated noise, as well as engine-related vibrations and hull flow characteristics. Managing these factors through optimized hull and propeller design, stable flow conditions and effective maintenance that includes limiting hull fouling, can significantly reduce noise levels. What improves passenger comfort on board also reduces disturbance to & marine ecosystems, especially marine mammals .
Exhaust emissions shape the onboard environment
Air quality is another aspect of comfort that passengers experience directly, particularly on open decks. In recent years, changes in fuel use and exhaust after-treatment technologies have influenced air quality outcomes on board cruise vessels. LNG combustion produces negligible sulphur oxides and virtually eliminates particulate emissions. Nitrogen oxides are reduced to very low levels, especially when combined with modern engine technologies.
For passengers, this results in cleaner air on deck, fewer odors and less residue on outdoor surfaces. For port communities, particularly those in enclosed or high-traffic harbors, the benefits are equally tangible. Cleaner exhaust reduces local air pollution and can influence how cruise operations are perceived in port communities.
The cumulative effect
Individually these steps may seem small, or may go unnoticed, but the impact can be significant.
For passengers, this consistency is rarely something they actively notice. For operators and port communities, it is increasingly critical.
They are now a baseline expectation for modern cruise operations.
