The HullSkater cleans boat bottoms to make them more efficient

Cargo ships are huge polluters—in 2015, as they traveled the ocean delivering everything from smartphones to bananas, they emitted more than 200 million metric tons of CO2, roughly as much as the entire country of Vietnam. Unlike cars, which can easily be replaced with electric versions, ships are harder to decarbonize. But a relatively simple intervention from a new type of underwater robot can help significantly shrink emissions.

Image: Semcon - https://www.fastcompany.com