Beneath the shimmering surface of the sea, a fantastic beast streaks through the blue abyss—the Super Sub, unveiled in all its glory at the Monaco Yacht Show. The three-seater submersible...

Long a mainstay go-to for undersea research and superyacht accessorizing, Dutch firm U-Boat Worx has released a steady stream of submersible models over the past two decades or thereabouts. From...