Aqua Quad is a new drone being developed at the US Naval Postgraduate School in Monterey. It is am amphibious quad-rotor than can land on water, lower a sonar sensor to detect underwater objects, and then take off again. It combines several features that together make it a step change in anti-submarine warfare: solar power gives it indefinite endurance; flight capability means it can travel long distances at high speed; swarming means that groups can combine to sweep a wide area.
Being small and cheap, Aqua Quad could be deployed in large numbers. It may be a game-changer for naval warfare.
Read the full story in New Scientist here.