Almost 70% of the cargo shipped around the world travels by boat, which means that if you could switch those boats from burning marine diesel to something more environmentally friendly, it would have a big environmental impact. Predictably perhaps, makers are looking at solving that.
The German Solar Boat Challenge sets strict rules for the length and width of the entrants—there are several classes, with different weight and size limits—but the strictest condition is that the boats shouldn’t carry batteries. They aren’t allowed to store the solar power, the power has to go straight from the panels to the propellers.
Controlled by a standard 2.4GHz radio controller the boats have to race between two buoys, competing both on speed and duration.
Victor Lapel—a maker from Lycée Maupertuis here in Saint Malo—showed me his entry and talked about the race where he’s competing in the lightest weight class. Because of the power constraints the boats have to be light. His boat is built from polyurethane coated in carbon fibre and has a 80W solar panel attached on top to drive the brushless motors. The power budget for the boat is a mere 50W—providing some leeway for cloudy weather—with just 18W of that as mechanical power to the propellors.