It’s no secret that superyachts are, well, expensive. The world’s largest private vessel, Khalifa bin Zayed Al Nahyan’s Azzam (Lurssen), reaches an astounding 180 meters (590 feet) and cost $600 million to build. In fact, eight of the ten most expensive luxury acquisitions of all time fall under the superyacht category.

And while a superyacht alone can cost tens — or sometimes, as in the case of the Azzam, hundreds — of millions of dollars, the annual upkeep costs can also reach into the seven figures, according to a report by Towergate Insurance.

So just how much does a superyacht cost? The reports finds that on average, a 100-meter superyacht with a top speed of 25 knots and 50 crew members should cost around $275 million. Considering the 30 largest superyachts are all longer than 100 meters, they can often cost significantly more.

The Worlds Largest Superyacht “AZZAM” Lurssen Yachts

Gas prices, general maintenance, taxes and crew salaries are typically the biggest sources of added expenditure for owners. Towergate estimates that annual dockage fees run for $350,000, insurance averages $240,000 and maintenance and repairs can be in the millions, as can crew salaries. Overall, the owner should expect to spend about 10% of the yacht’s initial cost on annual upkeep.

Captains report making anywhere from $70,000 a year on smaller vessels to $180,00 a year on larger vessels, while other members report significantly lower incomes. But considering the Azzam employs some 50 people, that’s quite a payout. Smaller vessels, including the 88.12-meter Maltese Falcon and the 79.25-meter Venus reportedly employ between 18 and 22 people. The Al Said, owned by the Sultan of Oman, employs 154 crew members.

Gas prices may be decreasing on land, but it’s a completely different story on the open water. A 71-meter yacht uses 500 liters of diesel few per hour, which brings the annual gas costs to around $400,000.

The Katara, a 124 meter superyacht owned by the emir of Qatar, docked in Nice’s harbor. (Valery Hache/AFP Photo/Getty)

What else does the report tell us about these impressive vessels? A lot about their owners, for one. Towergate found that of the nationalities of 125 owners it was able to identify, 14% were American, followed by Russians. But like most other luxury sectors, the biggest gains year-to-year were Asian owners, who purchased 11% of the superyachts delivered.

In 2016 355 superyachts were sold, totaling $3.4 billion. Ten-percent of yacht purchases are paid in-full immediately, and owners typically own their vessels for no more than three years before flipping them.

And price and length aren’t the only features worth bragging about. Many come equipped with bomb-proof windows, motion sensors, biometric fingerprint entry and escape pods. Venus, owned by Steve Jobs’ family, has a large pane of special glass around the side to resemble an Apple store. The Eclipse (Lurssen)  owned by Russian businessman Roman Abramovich, boasts two swimming pools and two helicopter pads, and a three-man “leisure” submarine.

Other notable superyacht owners mentioned in the report include director Steven Spielberg, America business magnate David Geffen and Greek hedgefund owner Elena Ambrosiadou.