(Ben Claassen III/Express) (Ben Claassen III/Express)

If you see a guy pedaling a bike across the Potomac River soon, don’t be alarmed. Be inspired. The dude with the floating wheels is Judah Schiller, 41, who’s on a mission to bring water biking to the masses.

The Marin County, Calif., cyclist was frustrated by the lack of a bridge bike lane over the San Francisco Bay — until he discovered a $1,500 Italian contraption that makes any road bike seaworthy. Schiller got comfortable with the pontoonlike equipment that attaches to the bike frame, and on Sept. 27, he made his maiden journey across the Bay.

Last week, he repeated the feat in New York by cycling across the Hudson River. As he travels to other cities to demonstrate the potential of water biking, Washington could be next up, says Schiller, who’s been researching the area’s bike community as well as its waterways.

Both seem ripe for what Schiller calls “a new aquatic frontier.”

Water biking has the potential to become a sport, he notes. When the water is still, it feels like road biking. When the waves start pounding, it feels more like mountain biking. And balancing is easier than it looks — although Schiller did fall in during one of his practice rides. (“You don’t need a helmet, but it is smart to wear a personal flotation device,” he says.)

Before competitors take it to the Olympics, however, Schiller expects to see commuters take it to work.

So when will that happen? Tim Payne, a principal with the transportation planning firm Nelson\Nygaard, advises me not to hold my breath. “Wind is a significant issue,” he explains.

But focusing on the water is a smart idea, Payne says.

“For 100 years, the Potomac River has been viewed as something to look at or build a bridge over. It wasn’t thought of as part of the transportation system,” says Payne, who’s been preparing a report for the Northern Virginia Regional Commission on the feasibility of harnessing D.C.’s rivers to expand its transit system.

The draft of the report, which will be released this month, declares that there are at least a handful of viable routes.

“A water-ferry system won’t take the place of Metrorail,” Payne says. But it could supplement an overtaxed system and help move more folks around increasingly congested Washington, he adds.

Willem Polak, owner of the Potomac Riverboat Company, is happy to give folks a lift. The tourist operation is gradually getting into the transportation business; Polak predicts that commuter trips will be more than half of what the company does within four years.

For some routes, Polak says, his boats can make the trip in about 15 minutes, while a car ride could take an hour and a half in rush-hour traffic.

The area’s not-so-hot land transportation links could pose a problem for ferries, however. Once the boat passengers are dumped off, they’ll need a way to get to the office or back home. Seems like a bike, even one that can’t ride on water, could help with that.