Three decades after seeing James Bond drive a car underwater in The Spy Who Loved Me, Frank Rinderknecht donned a scuba suit, got behind the wheel of a sleek Lotus Elise convertible, and headed into Switzerland's Lake Zurich. On that frigid day in December 2007, the water temperature was just 26 degrees Fahrenheit. "I was anxious and hyped—so I didn't feel the coldness at all," he recalls.

Rinderknecht started retrofitting cars in Zurich in the late 1970s. "I thought, Every man dreams of being James Bond, driving around in fast cars and getting the most beautiful girls in the world," he says. Since then, his Zurich–based company, Rinspeed, has designed dozens of concept vehicles, including one that drives on water. In 2000, Rinderknecht, who serves as a consultant for major auto manufacturers, set out to tackle an even bigger challenge: designing a car that could drive underwater, like the one in The Spy Who Loved Me.

To film the underwater scene in the movie, the production team used several Lotus Esprit sports cars modified with fins and closed-off wheel wells. To create the real deal, Rinderknecht added foam to a Lotus Elise convertible so it would sink less quickly. Next, he added rear propellers and replaced the car's internal combustion engine with five electric ones powered by rechargeable lithium ion batteries. To avoid an entrapment hazard, Rinderknecht decided to keep the top down, retrofit the car with a saltwater-resistant interior, and outfit the passengers with scuba equipment for breathing.

In 2008, Rinderknecht unveiled the Rinspeed sQuba at the Geneva Motor Show. He has no plans to manufacture the amphibious vehicle, which can dive to a depth of 33 feet and drive up to 4 mph on water and 2 mph under-water. For now, he is content to display it at auto shows a few times a year and do occasional underwater demonstrations. "You always have to live out your dreams," he says.