MantaDroid, an underwater robot inspired by manta ray fish

The robot can help carry out underwater mapping and ocean bed surveys, besides military reconnaissance.

Researchers in Singapore have built an underwater robot that looks and swims like a manta ray fish, using only single motors and flexible fins to propel through water in a manner uncannily like its biological cousin.

Academics have spent years trying to mimic the wing-like movements of rays' pectoral fins - but Chew Chee Meng of the National University of Singapore says it's the first to use single motors for each fin and rely on the interplay of fluid and fin.

Dr. Chew’s MantaDroid has a flat black PVC body with ray-like fins and two rear rudders, which moves through the water like its natural counterpart. He said that the fin’s passive flexibility allows it to interact naturally with the water, propelling it at a speed of seven-tenths of a meter (yard) every second, to cover about twice its body length.

The MantaDroid can swim for up to 10 hours and could help carry out underwater mapping and ocean bed surveys, besides military reconnaissance.