If you are a fighting ship aficionado, you probably also have at least a tangential interest in big yachts. Sometimes the line between the two categories of vessels blurs to the point of near indistinguishability. All my life I have been fascinated with the world's ultimate private ships, both old and new. Today, even in a competitive era of ever-larger mega yachts that can rival cruise ships in size, it's not just about mass, it's also about quality and creative ship design, which can border on downright genius. Maybe the smartest mega yacht of them all design-wise is the late Paul Allen's Octopus, an iconic vessel in the yachting universe and one that you can now own for $325,000,000—roughly the price of five G650 Gulfstream jets. The Microsoft co-founder and legendary entrepreneur's death has led to the liquidation of many of his most prized, but eccentric belongings. From the world's largest aircraft that was built to put satellites into orbit, to his mint and very flyable MiG-29UB Fulcrum jet fighter, much of the contents of Allen's incredible toy chest are being sold off to the highest bidder. His beloved Octopus is now part of what is something of the world's most outlandish estate sale.

Built by Lurrsen and delivered in 2003, at that time she was the world's largest yacht, but she quickly lost that crown as part of an ongoing competition among the world's yachting billionaires to have the biggest boat. Today she doesn't even make the top ten list in terms of length (414 feet), but she certainly does in terms of displacement, which sits just shy of 10,000 tons—eclipsing the displacement of a Ticonderoga class guided-missile cruiser.

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Octopus can accommodate 26 guests in 13 cabins, many of which are suites. Her crew of 63 is spread out in 30 cabins. Just as a reference here, at full load, she has a crew to guest ratio of nearly 2.5 crewmen per guest. For comparison, the crew to guest ratio on Royal Caribbean's Anthem Of The Seas has a ratio of .31 crewmen to each guest. The Seaborne cruise line's super up-market and small-sized ship fleet, like the Seaborne Odyssey, has about a .73 crewmen per guest ratio. Of course, during parties, the vessel can accommodate hundreds of people temporarily. Octopus has an incredibly classy exterior design that is somewhat timeless when compared to more exotic and bland looking yachts that sail the high seas these days. This is in part due to its purpose—it is both a pleasure yacht and an exploration vessel.

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The utilitarian half of Octopus's personality shows through in her overall design. Case in point, her large floodable well-deck in her stern that holds a yellow submarine named Pagoo. Pagoo can embark ten people on up to eight-hour-long underwater adventures. The sub can dive as deep as 1,000 feet. ISE Ltd. built the submarine, which has huge glass portholes for its occupants to gawk out of, for Allen.

Unknown Pagoo in Octopus's well-deck.