Inspired by the brilliant getaway mechanism of octopi and squids who use a blast of water to propel themselves away from danger, researchers at the Fraunhofer Institute for Manufacturing Engineering in Germany have developed a similarly stealthy propulsion system for boats and submarines. And it can be created with a single run on a 3D printer, meaning it has the potential to be a cheap alternative to traditional watercraft motors.

The prototype uses four flexible plastic spheres each with a hydraulic piston inside. Once flooded with water the spheres can be collapsed when triggered by a cable, expelling their contents and creating forward propulsion. Because the mechanism can be created using a 3D printer, the researchers feel it could be easily scaled up to propel a large boat at lower costs. And, by eliminating the need for a propeller, it would be considerably safer for other creatures sharing the water. It's an exciting breakthrough for anyone not aboard the Nautilus. [Fraunhofer-Gesellschaft via Gizmag]