This experiment is showing a tiny aerogel boat zipping for almost an hour on a drop of ethanol. This could lead to a lot of new ways of thinking about boat propulsion.
The ethanol on board vaporizes and passes through the aerogel's nanocellulose membrane and it lowers the surface tension of the water around the boat, which means less friction working against it and the surface tension of the water behind it increases, leading it to naturally push it along.
The material is still very expensive and difficult to produce, and it's no where near durable to survive even an ice cube sized obstacle for the time being, but it does open up a lot of new methods of thinking on how to reduce the drag on large ships which in turn could reduce their fuel consumption. Check out the experiment in the video below: [New Scientist]