In 2019, 30 million passengers are expected to take a cruise, according to the Cruise Lines International Association. To compete for customers, cruise lines are spending billions to outdo each other with outrageous amenities and entertainment, from a high-tech planetarium at sea to an on-board race track. Royal Caribbean alone is spending $200 million on a private island, CocoCay, in the Bahamas for guests, according to Bloomberg, and had a $115 million transformation on Navigator of the Seas ship, which has the longest waterslide at sea at 800 feet.
Now one of the latest over-the-top cruise is adventures is the first on-board roller coaster, which will be on Carnival Cruise Line's new Mardi Gras ship, and passengers will be able to ride it next year.
The Bolt Ultimate Sea Coaster will be on the top of the outdoor deck of the ship, according to Carnival Cruise Line, with drops reaching speeds of 40 miles per hour. The 10 fastest roller coasters in the world can go between 93 and 149 miles per hour, according to TripSavvy.
"Creating the first shipboard roller coaster posed quite a challenge as it's never been done," Glenn Aprile, Carnival Cruise Line's Director of Innovation tells CNBC Make It. "The design and movement of the ship needed to be factored in to the engineering and design, something that doesn't need to be accounted for on a land-based coaster."
The roller coaster is a Spike Coaster, a single-car, electric coaster where the passenger controls how fast or slow the cart goes with a pedal.
The coaster allows two riders in a "motorcycle-like vehicle" that races along a track 187 feet above sea level, offering 360-degree views of sea. "Kept at full throttle, the ride would take about a minute," says Aprile. The ride is also quiet, he says.
The coaster is made by Maurer Rides, a Germany-based company specializing in roller coaster trains and amusement rides. The company tested the first prototype in Germany in 2016, according to Coaster 101, a website dedicated to roller coasters and the amusement industry.
"The development of our new class of ship coinciding with Maurer's development of the all-electric Spike Coaster system worked out to be perfect timing," says Aprile. The roller coaster was a "multi-million investment," he says.
The Mardi Gras will also have "Family Feud Live" as an entertainment option. Guests will be able to play live against another family, mimicking the format of the TV show, where contestants guess the most popular answer to survey questions.
Princess Cruises has "The Voice of the Ocean," based on "The Voice" on NBC, a singing competition where participants perform in front of judges.
The Mardi Gras will also be home to a restaurant by New Orleans chef Emeril Lagasse.
Royal Caribbean's Harmony of the Seas has Jamie's Italian, a restaurant by British chef Jamie Oliver. Seabourn Cruise Line has The Grill by Thomas Keller, who helms The French Laundry, a famous restaurant in Napa Valley, California.
Mardi Gras will be the largest Carnival Cruise Line ship, according to the company, with 20 decks, 5,200 rooms.
The biggest cruise ship in the world is Royal Caribbean's Symphony of the Seas.
Disclosure: NBC is the parent company of CNBC.
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Correction: This story has been revised to reflect that the Navigator of the Seas ship had $115 million transformation.