When U.S. Marines landed at Inchon during the Korean War, they had to abandon their amphibious vehicles and cross tidal mud flats on foot. Today, the Navy uses the more versatile Landing Craft Air Cushion (LCAC) to move troops and supplies from ship to shore. But these hovercraft can't carry much cargo or crawl over obstacles. So the logistics of water-to-land transfers continue to bedevil planners and put lives at risk.

Since 2008, the Office of Naval Research (ONR) has been working with ship-design company Navatek to develop an entirely new kind of beach stormer called the Ultra Heavy-Lift Amphibious Connector (UHAC). The vehicle is unique for two reasons. First, it's massive. UHAC should be able to haul three U.S. Abrams main battle tanks at a time, compared to just one on an LCAC. Second, it's light. Air-filled foam treads give the fully loaded vehicle a ground pressure of just a few pounds per square inch—lighter than an adult human's footstep. "In places where a person would sink into the mud, UHAC would walk right over," says Frank Leban, deputy UHAC program manager at ONR.

The beast of a vehicle should be able to power up steep slopes, climb over 12-foot seawalls, and traverse just about any terrain: mud, sand, and even ice. The ONR most recently tested a half-size prototype in July, but it has yet to announce a release date for the full-size vehicle. Once it arrives, the amphibious craft could support military or disaster relief operations on almost any coastline in the world.