Senior Carnival executives reveal the considerations behind the LNG dual-fuel propulsion and design of Mardi Gras
Carnival Cruise Line’s largest ship, its first to be powered by LNG and the first cruise ship in the world to have a rollercoaster, has been delivered.
While it is Carnival Cruise Line’s first ship to be LNG fuelled, the Excel-class ship is parent company Carnival Corp’s fourth ship to be dual-fuel LNG powered. Explaining the reasons for deploying LNG power, Carnival Corporation senior vice president – maritime affairs Tom Strang tells Passenger Ship Technology “At Carnival, our highest responsibility and top priorities are compliance, environmental protection and the health, safety and well-being of our guests, the people in the communities we touch and serve and our shipboard and shoreside employees, so all considerations were grounded in that starting point.
“It’s important to remember that passenger cruise ships are roughly 3% of the global maritime fleet and generate a fraction of the overall emissions of the transportation sector. Nevertheless, every industry has a role to play in the worldwide effort to reduce fossil fuel emissions and their impact on global climate and public health. Among the cleanest fuels in the world, LNG significantly reduces emissions with cleaner exhaust.”
Mr Strang explains, “We chose LNG for the Mardi Gras propulsion system as it was becoming more widely available as a fuel source with a proven track record of safety with the LNG carrier fleet, while providing the best environmental option regarding the homeports and destinations we sail. Our relationship with Shell played a key role in our decision as well.”
Indeed, Mr Strang explains that Carnival worked closely with its fuel partner Shell on the supply side, and the Meyer Turku shipyard and its suppliers on the LNG equipment installation on Mardi Gras. “We relied on the expertise of our corporate shipbuilding team, our own internal LNG team and our sister lines, since other Excel-class ships have already been delivered and are operating on LNG, which offers many environmental benefits,” Mr Strang explains.
The configuration of Mardi Gras consists of three tanks filled with LNG that maintains its liquefied nature by being refrigerated at a very cold temperature – -259° F. Mr Strang comments, “In its liquefied state, LNG is odourless, colourless, more environmentally friendly and competitively priced compared with other fuels.”
LNG powers Mardi Gras’ propulsion system utilising Azipods and is used for all shipboard systems, from elevators, lighting and computers to galley equipment and its BOLT roller coaster.
Mardi Gras’ three LNG tanks have a total capacity of 3,620 m3, with two tanks of 1,550 m3 and one of 520 m3. Mr Strang comments, “Although the LNG tanks take up around twice as much space as conventional fuel tanks, due to careful design, the size of the LNG engine spaces is roughly the same as a ship with a diesel-electric propulsion system, so there were no challenges in this regard. Plus, Mardi Gras was Carnival Corporation’s fourth LNG ship, so we learned from the knowledge and experience of our sister brands that have operated ships with LNG which made the entire process smoother and more efficient.”
To fill Mardi Gras’ three custom-built LNG tanks, a fuelling barge will meet up with the vessel in Port Canaveral to provide enough fuel for its week-long voyages to destinations in The Bahamas and Caribbean. “Safety and environmental protection are the most important part of our LNG operation, including bunkering. Although Mardi Gras will be refuelled every week, it is actually designed to sail for up to 14 days before having to refuel,” says Mr Strang.
He adds, “The transition to LNG necessitated a host of new technologies and processes, both on board and on shore. New engine designs, fuel containment systems, and the accompanying new engine parts required countless hours of training for our shipboard officers and engineers.”
New terminal facilities were built at Port Canaveral to accommodate the LNG refuelling process, and purpose-built equipment is also required, such as an LNG fuelling barge and a fireboat. The port also expanded its firefighting training facility.
Green cruising platform
As well as LNG, Mardi Gras deploys many other energy efficient and environmentally friendly solutions. Mr Strang says, “The green cruising platform is part of our overall comprehensive sustainability effort across the company and its brands that spans every facet of operations, all with a singular goal of reducing our environmental footprint and protecting and preserving our land, water and air resources.”
Carnival Corporation has established a variety of goals, many of which have been met ahead of their established timetables. Examples from its 2019 Sustainability Report include:
Mardi Gras stands out as it has the first rollercoaster – BOLT – at sea. Carnival Cruise Line director of newbuild product development Glenn Aprile tells Passenger Ship Technology about the technical implications and considerations. “Placing a roller coaster on a cruise ship has never been done before and that obviously posed a variety of challenges, from tailoring the design for the shipboard environment, the logistics of installing the roller coaster at the yard, accounting for vibration on a moving cruise ship, space limitations and the effect of noise on other guests which was solved by using an all-electric coaster. It was a very complex process and one that took years of design, planning and implementation. We are very happy with the results thus far.
And as the largest cruise ship in Carnival Cruise Line’s fleet, there was a lot of careful planning. Mr Aprile says “Mardi Gras was five years in the making with roughly three years of planning and two years of construction at the Meyer Turku yard in Finland. As the largest Carnival Cruise Line ship ever constructed, careful planning went into every aspect of the shipboard operation, from designing the layout of the ship’s various public rooms and areas, to behind-the-scenes spaces like the galley, engineroom, crew accommodation and dining areas.
“Working in tandem with the yard and outside designers, our talented newbuild team looked for ways to maximise space and enhance passenger flow while at the same time developing exciting one-of-a-kind features like the BOLT roller coaster, the Grand Central atrium with rotating LED panels that open to the sea and the largest aqua park in the fleet. The results are simply spectacular, and we can’t wait for our guests to experience Mardi Gras for themselves.”
The ship has six themed zones. Mr Aprile explains, “With a ship as large as Mardi Gras we knew we had to create spaces that were as functional as they were beautiful, while enabling guests to feel connected to the ship and the sea. With that goal in mind, our designers came up with six distinct zones – The French Quarter, Grand Central, La Piazza, The Lido, Ultimate Playground and Summer Landing – each with a different personality.
“The idea was to create unique spaces that each features its own signature dining, beverage, entertainment and attraction spaces that our guests will enjoy. The diversity of spaces provides guests with a truly unique experience as they venture from zone to zone.”
He adds that in addition to the zones concept, designers created several areas with multi-deck openings such as the two-deck-high promenade that runs through the French Quarter. “The zones and the deck openings ultimately aid wayfinding on this larger ship. Creating zones was also an effective way of maximising space on board and enhancing guest movement,” Mr Aprile says.
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