Technology: Success on a Cushion of Air

To hundreds of spectators on England's Isle of Wight last week, it seemed for a moment as if the entire pier were suddenly roaring off into the water. What they actually witnessed, however, was the beginning of the maiden run of the SR.N4, the world's largest hovercraft. Driven by four 19½-ft. propellers and supported on a cushion of air, the 130-ft.-long, 76-ft.-wide craft moved smoothly into waters whipped into a frenzy by near-gale winds. As the London Times described it, "the huge amphibian lifted her skirts with commendable decorum and tripped into...