Today, we find the first modern warship -- on the ocean floor. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

One of the great adventures of the late twentieth century was finding famous sunken ships. We found the seventeenth-century Vasa in Stockholm Harbor and the Edmund Fitzgerald in Lake Superior. We found deep wrecks like the Titanic, the Bismarck, and the SS Central America. Another of those ships was the sunken Union Monitor.

The story of the Monitor and the Merrimack is often told in such a way that it seems to end with their famous duel at Hampton Roads in 1862. It did not, of course, but to understand what happened afterward, we must know something about the ships themselves.

Although their battle was a draw, the ships weren't at all alike. The South made its ironclad by hurriedly rebuilding the captured Union steam frigate Merrimack and renaming it the Virginia. Swedish-American engineer John Ericsson had designed the Union Monitor from the bottom up. Its flat top rode thirteen inches above sea level, and its low rotating turret was a radical new concept.

Both were river gunboats, unable to navigate the ocean outside Chesapeake Bay. When the South evacuated Norfolk, they had to scuttle the Merrimack. The Union Monitor also sank. It went down while it was being towed along the North Carolina coast in a terrible storm ten months later. At first, water sloshed in faster than the pumps could get rid of it. When the boiler went out, the men bailed while the ship's black cat sat wailing on one of the main guns.

The Monitor went down in 220 feet of water south of the Cape Hatteras lighthouse -- too deep for scuba divers to search. That's a vicious stretch of ocean. It's littered with wrecks. All attempts to locate the Monitor had failed before 1974. Finally a team led by John Newton of Duke University armed itself with side-scan sonar and high-tech photographic equipment. They located twenty-one other wrecks in the search area before they found the Monitor. It was further north than it should've been -- wind-blown that dark night until it finally carried sixteen men, and that black cat, to their deaths.

The Monitor finally revealed itself to the cameras -- a metal hulk 170 feet long and 40 feet wide. The famous pillbox turret was knocked off, and it peeks out from under the stern. But there we gaze straightaway into the beginning of modern naval warfare.

When the Merrimack sank, that was the end of it. It'd been a successful and inventive stopgap, but little more than a stopgap. The Monitor, however, was copied with little basic improvement until WW-I. The Union built a whole string of Monitor gunboats and made very good use of them during the rest of the Civil War.

Now the high technology of 1861 looms up from the dark ocean bed. There is the main drive-engine, the turret-engine, the screw-propeller drive, the rudder design, the well-conceived armor plate. What Ericsson really did is finally revealed; and the slow process of reclamation has begun. Now we see just why that strange, inconclusive duel 130 years ago changed naval history forever.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

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For more detailed accounts of Ericsson and of the Monitor, with references, see Episodes 695, 795, and 1344.

This is a greatly revised version of Episode 151.

The Monitor in Cross-section