The Swiss Firm MW Line makes solar boats that are ferrying people around lakes and rivers in Switzerland, France, Italy, and the United Kingdom. The only backup power, apparently, is on-shore charging from the grid. They’re also the shipbuilder for the PlanetSolar project which plans to have a solar-only craft in the water ready for a two-person, 120-day around-the-world trip in 2009.

The New York Times reported on January 4th that New York Water Taxi, the only operator of Queens/Manhattan and Brooklyn/Manhattan ferry service has cancelled service for the winter – largely because of fuel price increases. That notwithstanding a monthly subsidy from the real estate developers who established Schaefer’s Landing, a high-end project in Williamsburgh. A ferry powered by photovoltaic cells wouldn’t be directly affected, if at all, by petroleum price increases. Given the relatively short distances involved, on-board solar panels and batteries could be supplemented with electricity dockside. If that electricity is generated via wind (often best captured on or near water) or solar, ferry operating costs could be insulated from petroleum price fluctuations.