Hot tubs and grand pianos have become almost passé in the world of megayacht builders and their billionaire clients. Onboard the latest and most extravagant yachts, these luxury amenities are standard, right alongside medical suites, basketball courts and helipads. Sure Larry Ellison’s 453-foot Rising Sun has an extensive wine cellar, but a boat well stocked with vintages is only the beginning of luxury living on the high seas. Here’s five more over the top amenities that megayacht sailors apparently can’t live without.

Submarines

Looking out over the ocean isn’t as appealing as heading down under, and we’re not talking about Australia. Octopus, the largest yacht in Microsoft co-founder Paul Allen’s fleet, carries an eight-man submarine capable of spending up to two weeks under the sea. The sub is launched through an underwater hatch in the ship’s hull, which closes and drains on the sub’s return. Another other megayacht in the planning stages, Eclipse, being built for a billionaire Russian oil magnate, is also expected to have a submarine on board. Photo: U.S. Submarines

Fiber Optic Masts

Maltese Falcon is no ordinary sailboat. Besides being just shy of 289 feet, this yacht moves under the power of 15 sails raised on three carbon fiber masts that rotate to better harness the wind. These “smart masts” were designed with a fiber-optic sensor system that gathers data on wind speed, force and the strain being placed on the masts. An actual crew still does the sailing, assisted by the computerized monitoring system.

Outdoor Cinema

Mirabella V, the largest single mast yacht at 247 feet, boasts the usual amenities. Most megayachts have movie theaters onboard, but the Mirabella V takes one step further into luxury with its outdoor cinema. A projection screen on the sky deck allows guests to watch movies under the stars with wireless headphones. The ship, which sails the Caribbean in the winter, rents for $300,000 a week (the price jumps to $350,000 over Christmas and New Year’s week) and up to $375,000 for a seven day sail during the high summer season in the Mediterranean. Photo: Benoit Donne, yacht-images.com

Disco

Available for charter, the 400-foot Lubecker Flender 40 resembles a floating 5-star hotel, complete with spa and salon. But the feature that caught our eye is the full-size disco. Guests can dance the night away with 60 friends and spend the next day snoozing in the sun on the top deck. Travelers aboard the 223-foot motor yacht Kismet can also get their boogie on. Kismet’s bridge deck includes a circular disco, complete with strobe lights and a circular bronze carving of New York skyscrapers.

Garage

Almost all megayachts have tenders, smaller boats used for water skiing, exploring or trips into harbor. Kismet has an actual garage to store its two 25-foot tenders. These boats are launched through wide upward swinging doors, using a beam crane. Another motor yacht, Princess Mariana, has a dry dock for her tender which, when the boat is out, can be flooded to create a 12 meter swimming pool illuminated by underwater lights. Talk about doing laps in the parking lot. Image: charterworld.com