This solar powered boat from Hammacher is capable of ferrying up to 4 adults with a 700 Watt electric motor that moves it silently at 5mph. The motor is powered by four deep cycle batteries that are constantly recharged by the sun during daylight hours, even when overcast. Because the batteries hold up to a 6-hour charge, the boat can be used at night as well; for extended night operation the batteries can be recharged from an outside source.

Source & Picture: Ecofriend