While in Australia recently, I took my boys on a trip up the Maroochy River into the Maroochy wetlands. We had all enjoyed our canoe trip into the Noosa Everglades the previous year (https://mountainsrivers.com/2018/09/06/canoeing-in-the-noosa-everglades/) but this time we had a solar-powered canoe. The solar panel charges a battery that runs an electric outboard motor. It produces a reasonable speed and is very quiet. And we certainly appreciated the ease of gliding upriver without effort.