From a distance, Tatsuro Yokoi looks like a pirate clinging to the mast of a sunken galleon.

Move closer ¡ª sorry, make that swim closer ¡ª and you notice he lacks the eye patch, the parrot on the shoulder and the hook for a hand. You also notice that he is actually moving at a fair clip and is standing on what looks like a small, semisubmerged airplane with its short wings angled down into the water like a shark¡¯s side fins.

Did somebody say ¡°shark¡°? You don¡¯t want to do that ¡ª not when you¡¯re swimming 100 meters from the Zushi shoreline in Kanagawa Prefecture chasing a product- designer-turned-inventor as he tests out the latest version of the one-man waterborne vessel he¡¯s named the Swing Roll Flipper.