In the 1860s sailing ships still dominated most navies, although some had an additional power source in steam engines. But sailing ships had just about peaked. Among the fastest were Yankee clippers but that was as fast as any sailing ship was likely to get. The introduction of the engine and screw propeller represented a quantum leap. It was all very much like the replacement of propeller-driven aircraft by jets during and after World War II.
In 1862, the second year of the Civil War, the North was bottling up the inlets at Hampton Roads, Virginia, near Norfolk. Perhaps a dozen Yankee sail-driven warships were stationed there.
And then, from up the river, came the monstrous Confederate Southern Ship "Virginia." It was originally the USS Merrimack, burned to the waterline and sunk when the North first abandoned Norfolk after the secession of Virgnia. The Confederates, lacking much in the way of iron works, raised the hull and built a casement on it that resembled a long pup tent. The casement was built of alternating layers of hard oak and steel and had fourteen gun ports. It was built at a 45 degree angle to deflect enemy shot, and a steel ram projected from her bow, just as in ancient Roman ships.
No one had seen another ship quite like it, a large, heavy, brutal, and practically impermeable warship. But the Merrimack did have its weaknesses. It used the obsolete and almost worn-out original engine and, at four or five knots, was very slow. Its turning radius was one miles and it took 45 minutes. These weaknesses didn't prevent the Merrimack from sinking two Yankee ships and running a third aground. At that point, with night approaching, she disengaged and retired, planning to finish the job the next morning.
But the next day, before the Merrimack could get off a shot, an even queerer ship entered the harbor, the US Navy's "Monitor" -- a cheesebox on a raft, as one observer put it. The Monitor was smaller than her opponent and carried only two guns, but they were in a revolving turret and the principal parts of the hull and superstructure were made of thick steel armor. The hull of the Monitor was shorter and all but eighteen inches of it were below the surface of the water and so invulnerable to enemy shot. It was more maneuverable than the Merrimack and faster.
Briefly, the two ships pounded each other throughout the day until darkness again brought about the retirement of both, each ship thinking it had forced the other to retreat. They never faced one another again and both had brief lives. Trapped by advancing Federal troops, the confederates sank the Merrimack to prevent her capture. The Monitor wasn't seaworthy and sank with the loss of a dozen hands off the Carolina coast. But both designs had a powerful impact on marine design. By the end of the war, the rivers of the US were filled with Merrimacks and Monitors.
That's a relatively objective view of the encounter but I can't help imagining what it was like inside the ships, filled with smoke, jarred by cannon shot. It must have been particularly hellish for the men tending the engines below decks. And in the Monitor, anyone caught leaning against the inside of the turret when it was hit by a shell would be knocked unconscious by the shock. The noise must have reached some sort of threshold of tolerance.
