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It used to be, if you traveled on a ferry boat, you resigned yourself to a slow trip. Today, high-speed ferries have changed the pace of sea travel. But progress has come with a price, in the form of giant, man-made waves in---Our Ocean World.

A few summers ago, in an English coastal town, sunbathers had to run for their lives when a thirty-foot wave reared up out of a flat-calm sea. In another incident, a man drowned when his boat was swamped by a wave that "came out of nowhere. " Investigators think these and other rogue waves were generated by high-speed ferries.

Research reveals that high-speed ferries cruising through shallow water may generate a very unusual kind of wave. It's called a soliton or "solitary wave. " Normal waves have a peak and a trough. So when the wave hits the shore, the water in the peak falls back into the trough. On the other hand, solitary waves, have a peak but no trough, so they hit with tremendous force-- with nowhere for the moving mass of water to go.

Some ferry lines are monitoring their boats, to make sure they're not making waves. I'm Marilyn Cooley.

Our Ocean World is produced in cooperation with the National Oceanic and Atmospheric Administration-NOAA. Learn more about our natural world.