WatMan specifies Danfoss for the world’s largest cruise ship’s SWRO plant

When Royal Caribbean and Meyer Turku announced the order to build the first two ships of the Icon Class back in 2016, it was clear that these cruise ships would be different. Not only would they be the world’s largest, at 250k gross tons and 365 meters, but they would also be designed to set new standards for energy efficiency and require lots of fresh water.

As with most new ship classes, key technical specifications were defined early in the process to support consistency across the series. The SWRO system formed part of these specifications.

Among other innovations, Icon of the Seas is powered by liquid natural gas, LNG, to reduce greenhouse gas and particulate emissions. The ship also uses fuel cells to produce electricity, including the power required for desalination, which provides most of the vessel’s fresh water. With a maximum capacity of 7,600 passengers and 2,350 crew as well as the world’s largest floating water park, the ship needs plenty of it.

“When fresh water plays such an important role for the guest experience at a scale like this, energy efficiency and reliability were among the most important criteria for this project,” explains WatMan’s Managing Director, Juha Lintujärvi. “However, even though there is more room for everything on a ship of this size, making optimal use of available space is always important in marine SWRO applications, too.”

WatMan won the bid for the Icon Class SWRO plant with a four-train design built around Danfoss components. Each train comprises an APP 53 high-pressure pump and an iSave 70 ERD.

“We have a lot of experience designing SWRO for cruise ships,” says Lintujärvi, “and energy efficiency is always critical for these projects because of its financial and environmental consequences. That is one key reason to specify Danfoss pumps and ERDs, which we believe are the most energy-efficient options currently available. But Danfoss components also facilitate flexible and reliable solutions. Rather than working with standard configurations, we tailor each plant design to very specific customer demands and focus on total quality control throughout the design, production, and commissioning phases. This approach maximizes our value add for our customers. The flexibility and dependability of Danfoss’s products and the technical support from their team help us deliver this.”

The SWRO plant aboard Icon of the Seas, in service since January 2024, provides clear proof of how the selected configuration performs under real cruise conditions. The system was designed to meet Royal Caribbean’s rigorous energy efficiency requirements for the Icon Class, and operational experience from the first vessel confirms that it consistently delivers on those targets in daily operation.

Reflecting on the first two years of operation aboard Icon of the Seas, Lintujärvi notes:
“Energy efficiency was a key requirement from the beginning, and the plant on Icon has fully lived up to the stringent SEC targets. Furthermore, we’ve seen stable, predictable operation since commissioning. In fact, the first APP pumps have now been running for close to two years without requiring any service whatsoever. There have been no service calls and no maintenance actions on the pumps, which is important for us and our customers in terms of operational continuity.”

The SWRO configuration developed for Icon continues to demonstrate its suitability in operation and has been specified for all subsequent vessels in the series to date. Star of the Seas entered service in August 2025, and Legend of the Seas is scheduled to begin cruising in July 2026. WatMan is currently working on the fifth ship in the series, with options in place for additional vessels.