You sometimes get the impression that Tesla CEO Elon Musk says wild things just to gauge people's reactions. You have to be crazy to think that the Hyperloop is ever going to happen. Train travel is barely accepted in much of the country. Recently, he boasted in an interview with Britain's The Independent newspaper that he could build a flying car and a submersible one. If he's to be believed this time, one of them might actually happen.
Science often looks to nature for inspiration on how to improve a concept which is already used. Just as flippers help a swimmer or diver to move through the water, the same principle could replace the propeller that is normally used in submersibles. Specifically, the bluegill sunfish is being studied by researchers from MIT as a way to make better unmanned submersibles. Apparently, the bluegill has a distinctive swimming motion which is optimal for producing forward thrust. They cite military n