Dutch diving expert U-Boat Worx unveiled a 37.5-meter underwater superyacht concept called Nautilus at the Monaco Yacht Show. Nautilus can function as both a surface vessel and a submarine, with a depth rating of over 200 meters. The diesel-electric model can travel at a surface cruising speed of nine knots and a submerged speed of four knots, and can stay underwater for up to four days at a time. Its underwater endurance at cruising speed is six hours. Nautilus can be docked at any pier that can accommodate its 6.5-meter draft when not in use.

When used as a yacht, Nautilus features various relaxation and entertainment facilities, including a freshwater pool, a bar, and a dining table for guests on a large sun deck. When the sub is submerged, this open-air arrangement can be retracted. Inside the sub, there is a 50-square-meter dining and lounge area with four circular windows measuring four meters in diameter. The suggested design for Nautilus includes a master cabin and four additional cabins, as well as sleeping quarters for up to six crew members. However, the interior layout is highly flexible and can be tailored to the owner's preferences.

In other areas of the superyacht, a pressure-resistant electric tender named Aronnax is housed beneath the aft deck. The tender can also transport up to five scuba divers to the targeted diving location underwater.

U-Boat Worx President and Founder Bert Houtman stated, "People who decide to purchase a yacht will now have to consider whether their chosen vessel can dive up to 200 meters." He highlighted numerous advantages of Nautilus, including its effectiveness in dealing with sea sickness. "If the sea is very rough," Houtman said, "just dive and continue your journey comfortably. The yachting market will never be the same again with Nautilus."