With six legs, 30 joints and a laser-guided two-metre–long robotic arm, the Crabster CR200 has built-in advantages when it comes to deep cleaning hard-to-reach mucky corners.

The giant crab robot was developed a decade ago by researchers at the Korean Institute of Ocean Science and Technology (KIOST) to inspect wrecks and scour the seafloor in tricky tidal currents. With some retooling, it will now be put to the test for the great shipping challenge of the 21st century — bringing down harmful emissions.