- The Captive Air Amphibious Transporter has inflatable treads that push on the water like paddlesboat paddles.
- The machine crawls across watery surfaces as well as sand, mud and ice.
When U.S. Marines assaulted Pacific island strongholds during the last years of World War II, they relied on amphibious tractors capable of swimming with their tank treads. Today, the U.S. military has begun testing inflatable tank treads to carry supplies from ship to shore during disaster relief operations.
The inflatable tanklike treads of the Captive Air Amphibious Transporter (CAAT) can separate into flat panels to push on the water like a paddleboat. That enables the CAAT to not only swim, but also to crawl across sandy beaches, mud, ice fields and even sea walls -- making it ideal for delivering cargo or troops in harsh conditions following a mega-disaster such as an earthquake or tsunami.
"The CAAT works very much like a tank, with moving tracks that are driven by a sprocket or drive wheel," said Scott Littlefield, program manager for the U.S. Defense Advanced Research Projects Agency (DARPA). "However, unlike the metal treads on a tank, the CAAT has large buoyant treads, that are either inflated with air or filled with a lightweight foam."