Numbers are at pre-Great Recession levels, according to the National Marine Manufacturers Association. SARASOTA — From a distance, the crown jewel of this year’s Suncoast Boat Show doesn’t look much like a boat at all. When you approach it, it looks more like a two-story restaurant with sliding doors on the main floor, a luxurious outdoor lounge area and a roof deck up top. You might also forget that it’s a boat once you’re standing on it, because the floor literally does not move. The three-story, 84-foot long, 9,100-square foot yacht has five staterooms, each with its own king-sized bed and bathroom, a roof deck, a downstairs with plenty of space for a TV area and game room, and a chef’s kitchen in a living room where there’s more than enough space for big parties. There’s 4,700 square feet of air-conditioned space, it’s made of stainless steel, and the yacht plus all the furniture and accoutrements you see on it can be yours for just $12 million.  The Rendezvous 2018, a “mansion yacht” also known as the “cube” made by Cubic Yachts, debuted on Friday at the 37th annual Suncoast Boat Show. The event, which...