The size matters

Royal Caribbean International's latest cruise ship, Oasis of the Seas, is a giant. The vessel is 360 meters bow to stern, is 47 meters abeam, and measures 225,000 GRT. With 18 decks, it towers 65 meters above the waterline, displacing about 100,000 tons of water. When it begins service in December, it will have space enough for about 6,300 passengers and 2,100 crew members, making it the largest cruise ship ever constructed.

But according to Harri Kulovaara, Executive Vice President (Marine) of Royal Caribbean International, the size of the vessel is only part of the story. "We did not build the largest cruise ship in the world to break records," he says. "Oasis of the Seas is large for one reason – to enrich the passenger experience."

Putting the passenger first

Indeed, the space onboard allows for some unique features. Kulovaara explains that by dividing the vessel into distinct areas, passengers are afforded a more personalised experience. "During the concept development phase, we settled on what we call a neighbourhood concept – one that would allow passengers to move through six different areas of the vessel, each with its own unique character," he says.

To realize these ambitions, RCL recognised that the vessel would not only have to be large, but include some innovative ship design solutions. After working closely with STX Europe, the company settled on a unique approach – a split super-structure. Indeed, According to Kai Levander, who recently retired as Senior Vice President of naval architecture for STX Europe, Oasis of the Seas represented an enormous technical challenge.

Rethinking ship design

"From a naval architecture design perspective, we had to rethink how passengers and crew move around the vessel, both from a safety perspective and to avoid congestion," he says."But our experience with previous Royal Caribbean vessels helped, and we got a lot of support from their high quality technical staff, which made a big difference."

The size and split superstructure of Oasis allowed RCL to equip the vessel with significant improvements in passenger facilities and services. In addition to some familiar modern day cruise ship features, such as a skating rink, climbing walls and multiple swimming pools, Oasis has six distinct neighbourhoods, such as the Boardwalk -- complete with a carousel – a fully equipped sports zone and an open air park, planted with more than 12,000 flowers, plants and trees.

Passengers will have a broad range of choices, including an adults-only solarium, miniature golf, a water park for kids, a basketball court, spa and fitness centre, twin outdoor Flowrider surf simulators, an outdoor water-themed amphitheatre, the traditional working carousel, and the dozens of shops, restaurants, and bars – including one that is mounted on hydraulics, so it can travel between decks. And with more than 2,000 balconies and 28 two-story loft suites, passengers have a wide range of top cabin classes to choose from.

"We have neighbourhoods which will appeal to children, teenagers, families, and couples of all ages," says Kulovaara. "While the scale of Oasis is certainly impressive, what makes Oasis unique is not its size, but the variety of activities and different experiences we can offer."

A spirit of collaboration

To execute this concept, RCL relies on a broad network of trusted, long term suppliers. According to Anders Aasen, RCI's Associate Vice President, Marine Technical Services RCL's close cooperation with suppliers is in part a reflection of changes in the shipbuilding industry. "Over the past decade, shipyards have embraced an outsourcing production model," he says. "In addition, the increased size and complexity of the vessels we build demands close cooperation, so we tend to work with companies and people who share our values and business culture."

Aasen says the company has embraced what he calls a "cost-sharing" model of development. "We work in partnership with suppliers to develop better solutions," explains Aasen. "We get a better vessel, and they get product refinements that help them gain market share." Aasen notes that unlike many competing cruise companies, RCL employs many experienced engineers and technicians, who not only verify design concepts during the development process, but contribute valuable ideas. "We take an active role in every aspect of vessel design, and expect our suppliers not only to work well with us, but with each other."

Cruise control

One area where suppliers worked closely together with RCL is in the bridge control system. With six diesel electric engines supplied by Wartsila delivering close to 100 MW of power to four large 5MW bow thrusters and three 20MW podded azimuth propulsion systems supplied by ABB Marine, Oasis has a powerful propulsion system. To transfer all that power to the bridge fell to Kongsberg Maritime which was contracted to supply the propulsion control system and the dynamic positioning (DP2) system. In addition, Kongsberg provided power management, machinery automation and HVAC automation systems.

Captain William (Bill) Wright, Senior Vice President of RCCL, and the Captain of Oasis of the Seas says that many different components had to come together to make the system meet RCL's requirements for such a large vessel. "Oasis has about 15,000 square meters of sail area, so manoeuvring the vessel in and out of small or busy ports in challenging wind and sea conditions requires a powerful and dynamic propulsion control system," he says. "We worked closely with Kongsberg Maritime to ensure we got the right bridge control system and functionalities in the software solution to match our needs."

Customising DP

Indeed, Captain Wright was heavily involved in the control system from concept development to the factory acceptance test, and will continue to offer feedback as he becomes more comfortable at the helm. In addition to making suggestions on the position of certain control throttles on the bridge, Captain Wright (who has experience using DP systems from his career in the offshore industry and other RCL vessels) suggested some software refinements to ensure the system's redundant DP system was optimised for the Oasis. "There were some functions we didn't need and others we wanted, and with KONGSBERG's help, we ended up with a system which meets our requirements," he says. "In fact, there are elements to the DP system aboard the Oasis which I am confident would be of interest to the offshore industry."

According to Rolf Taxt, Kongsberg Maritime's Project Manager (Integrated Control Systems), the company places a high value on the input delivered by RCL personnel. "Oasis is among the largest, most challenging projects we've ever worked on," he says. "It is a credit to RCL's personnel and the yard that everything has gone smoothly. If they don't like something, they let us know, and we fix it. We both want the best solutions, not conflict."

Taxt says that RCL challenged Kongsberg maritime on a number of systems. "In addition to customising the DP software and bridge control systems, RCL wanted wide-screen monitors, which allows us to make available more information on screen for bridge officers," he says. "We believe more shipowners will go for larger aspect ratios in the future, and thanks to our work with RCL, we can deliver." Taxt notes that fuel economy and reduced emissions are key parameters for RCL and the systems installed on Oasis are designed to reduce power consumptions and includes monitoring of the effectiveness of the machinery and AC plants.

20,000 points

Yet the greatest challenge for Kongsberg Maritime involved the design of the automated climate control system (HVAC) for all the vessel's public spaces. "At Kongsberg Maritime, we measure the size and complexity of an automated system by the number of electrical points," he says. "Oasis required more than 20,000 points, making this project the largest we have ever installed aboard a vessel."

Taxt says the company has had experience with similarly complex systems on offshore installations, but says the Oasis (and its sister vessel, Allure of the Seas, now under construction) was unique. "RCL projects are highly demanding, but we welcome the opportunity to expand our competence, product range and experience delivering large and complex automation systems," he says. "Working with RCL has made us a better company."