Billionaire Yachts: Who Has The Biggest, Most Expensive Ship?

Amazon founder Jeff Bezos is building a megayacht that is set to be the biggest sailing yacht in the world when it launches this summer.

Bezos' megayacht first made headlines last year when Brad Stone revealed in his book, "Amazon Unbound," that the billionaire commissioned a 127-meter (417 feet) custom yacht from the Dutch shipbuilder Oceanco.

Bezos' $500 million megayacht, Y721, is still being built in Rotterdam, Netherlands, but it will be the largest sailing yacht in the world when it's finished, beating the ships of fellow billionaires such as Google co-founder Sergey Brin, Oracle co-founder Larry Ellison and media mogul and new People magazine owner Barry Diller in terms of size, the New York Post reported.

Brin's $81 million yacht, the Dragonfly, is 240 feet long and features an open-air cinema, jacuzzi and sundeck that converts to a dance floor.

Ellison's $160 million sailing yacht, called Musashi, is slightly bigger, spanning 288 feet. It is equipped with a spa, swimming pool, outdoor gym and movie theater and costs at least $10 million a year to run, according to the outlet.

IAC chairman Diller's sailing yacht, the Eos, is even bigger. The 305-foot-long ship cost $200 million to make and features a pool on the top deck and a figurehead of Diller's wife, fashion designer Diane von Fürstenberg, that was created by sculptor Anh Duong.

When Diller and his wife bought it in 2009, the boat was the largest private sailing yacht in the world.

Meanwhile, the sailing yacht of Bezos, who is currently the world's second-richest man behind Elon Musk, has space for 18 guests on board and will require a crew of 40. Inside, it is said to be modeled on Diller's yacht.

Bezos has reportedly commissioned a second, smaller "support yacht" that will include its own helipad. Bezos' girlfriend, Lauren Sanchez, is a helicopter pilot, and according to Stone's book, the Amazon founder has taken flying lessons as well.

The main yacht is unable to support its own helipad due to the three sailing masts on its deck.

The smaller yacht is also expected to be loaded with cars, luxury speedboats, and probably even a submarine, according to experts.

Bezos' larger yacht is so big that even without the masts, it reportedly stands at over 131 feet tall. Konigshaven Bridge, known as De Hef, would have to be dismantled in order to get Bezos' megayacht out of the Rotterdam harbor where it is being built, the BBC reported.

A spokesman for Rotterdam Mayor Ahmed Aboutaleb confirmed the plan to reporters in February. Bezos will foot the bill through Oceanco, the rep said.

"It's the only route to the sea," a mayoral spokesman added.

Some are not on board with the plan, with Rotterdam politician Stephan Leewis tweeting of Bezos: "This man has earned his money by structurally cutting staff, evading taxes, avoiding regulations and now we have to tear down our beautiful national monument? That is really going a bridge too far."

Oceanco declined to confirm that Bezos had commissioned the new boat, according to the New York Post.