“Rupert works all the time,” one broker said. “He loves the boat, he loves to sail, but he doesn’t really use it much.”

The yacht was built in 2006 by Perini Navi, the Italian shipyard known for its luxurious, sleek sailing yachts. Rosehearty has a crisp, modern interior by French designer Christian Liaigre, with five suites for 10 guests, including two VIP suites. The main mast of the yacht towers at 193 feet, and it has a sail area of 16,792 square feet.

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The boat also has lots of “toys,” including water skis, a wakeboard and full sets of diving gear. The deck features a large Jacuzzi.

It’s fully equipped for a media mogul, with wireless Internet and plenty of plasma televisions in the cabins.

—By CNBC’s Robert Frank. Follow him on Twitter @robtfrank.