Researchers in the USA have been researching technology that lets boats or small aquatic robots glide across the water without the need for an engine, sails or paddles.

A team of researchers from the University of Pittsburgh has designed a propulsion system that uses the natural surface tension that is present in the water and an electric pulse to move the boat. The system has no moving parts and the low-energy electrode that emits the pulse could be powered by batteries, radio waves, or solar power, researchers said.

The system mimics the propelling skill of some insects that float on the water and move by leaning one way or the other. Researchers said they were inspired by the way beetle larvae move on water.

A wriggling beetle larva might repulse the average person, but Pitt professor Sung Kwon Cho admired the way they get around on water

Like any floating object, larvae resting in the water cause the surface tension to pull equally on both sides. To move forward, the larva bends its back downward to change the tension direction behind it. The forward tension then pulls the larva through the water, said Sung Kwon Cho, senior researcher and a professor of mechanical engineering and materials science in Pitt’s Swanson School of Engineering.

One of the system’s primary applications could be as a cheap, environment-friendly robot that could traverse the world’s oceans, gathering research data, Cho said.

The researchers said that in their experiments, an electrode attached to a 2cm long ‘mini-boat’ emitted a surge that changed the rear surface tension direction and propelled the boat at roughly 4 millimeters per second. A second electrode attached to the boat’s front side served as the rudder.

An abstract of Cho’s mechanism is available on Pitt’s Web site