To build the first battery-powered bubble-shaped ships that hover a few inches above the water and transport as many as six people at a time, founders Alain Thebault and Anders Bringdal last month raised 3.45 million euros ($3.6 million) from French insurer Maif and venture-capital fund Partech Ventures.

SeaBubbles is eyeing around 10 times that amount in the next round, and is talking to investors in France and the U.S. to raise it by the second quarter, Thebault said in a phone interview.

"Every city is getting more and more crowded, with traffic jams on land, whereas waterways are abandoned," Bringdal, who together with Thebault broke the record for speed on a floating sailboat they'd designed in 2009, said in a separate interview with Bloomberg Television. "In San Francisco we can save people an hour a day going from downtown to the Silicon Valley and back."

San Francisco is one of the key places the entrepreneurs have pitched to potential customers over the past weeks. SeaBubbles is also discussing items like autonomous driving and battery-charging with potential partners as it seeks to evolve its cabs. The boats, recharging docks and a taxi-hailing app will be ready to demonstrate in Paris in June.