Damn the Torpedoes!”: Naval Mines

^{From the Connecticut River Museum, Essex, Connecticut}

^{Reproduction of David Bushnell’s submarine, American Turtle, which failed to place a mine beneath a British frigate in 1776. This model, in the Connecticut River Museum in Essex, Connecticut, was actually tested and found to work as a navigable submarine.}

^{Drawing showing how Bushnell’s Turtle was operated.}

It was 1864, and only one port in the Confederate States – Mobile, Alabama – remained open. Now David Glasgow Farragut, commanding a fleet of four ironclad monitors and fourteen wooden ships, was attempting to close it. Mobile was heavily fortified, and in its harbor was the C.S.S. Tennessee, a huge armored ram, a larger version of the famed C.S.S. Virginia (nee Merrimack).

Farragut was on the wooden frigate Hartford. When the battle began, Farragut wanted to be able to see what was happening, and he could get a better view from the tall Hartford than from one of the low‑lying monitors. The old sea dog climbed a mast so his view wouldn’t be obscured by the smoke of Hartford’s guns. Farragut was not a young man: he was a veteran of the War of 1812. So a quartermaster tied him to the mast for safety. His age and long service in the navy had not made Farragut a tactical conservative. He sensibly positioned the monitors between the Confederate Fort Morgan and the more vulnerable wooden ships.

Suddenly, the water under the lead monitor seemed to explode. The armored ship lurched, tipped up, and sank like a piece of iron. The Union fleet stopped.

“There are torpedoes ahead,” someone told the commodore.

“Damn the torpedoes! Full speed ahead!” the old man yelled.

Crewmen on Hartford later said they could hear the “triggers of the torpedoes snapping” as the flagship steamed past them. Fortunately, none exploded.

Then Tennessee tried to ram the Union flagship, but Farragut’s frigate was too agile for the armored monster. The monitor U.S.S. Chickasaw got behind Tennessee and pounded one spot with 11‑inch cannonballs until it made a breach in the big ram’s armor. Chickasaw continued firing and the Confederate flagship filled with smoke. One shot cut the ram’s tiller chain, and another injured Confederate Admiral Franklin Buchanan. The Confederate ship surrendered.

Farragut had closed the last Southern port in spite of the torpedoes.

The torpedo (what we call a mine today) was a relatively new weapon in 1864. A few years before then, in 1829, a 14‑year‑old Yankee inventor named Sam Colt had demonstrated how an underwater powder charge could be set off by electricity. The demonstration did not increase young Colt’s popularity: Onlookers were showered with muddy water, but Colt showed how devastating a small charge of explosive could be when exploded against a boat under water.

The water tamped the explosive, so that the greatest force of the explosion was directed against the boat.

The Russians used mines during the Crimean War of 1855‑56, but no ships were sunk. The first ship sunk by a mine was the gunboat U.S.S. Cairo at the Battle of Yazoo River in 1862.

In 1866, a Scotsman and an Austrian invented a new kind of torpedo – one that went after an enemy ship instead of waiting to be hit. At first (as we’ll see in Chapter 26) the new weapon was called a “locomotive torpedo.” Later, it became simply the torpedo. That meant there had to be a new term for the stationary weapon. For centuries, stationary explosive charges had been placed in tunnels under enemy positions – in a mine (one that was dug to put something in rather than take something out). So the explosive charge buried in water instead of land became the naval mine or simply the mine.

Although the new torpedo could chase enemy ships, the old mine did not become obsolete. Far from it. Mines have become a key part of just about all wars that involve ships. Weak naval powers depend on them heavily. Mines cost less than ships, but few ships can hit a mine and avoid a trip to Davy Jones’s Locker. Strong naval powers also used mines extensively. Both sides used mines in the Russo‑Japanese War. The Russians lost a battleship, a cruiser, two destroyers, and a couple of smaller ships to Japanese mines. The Japanese Navy suffered more losses from mines than from any other weapon – two battleships, four cruisers, two destroyers, a torpedo boat, and a minelayer. In World War I, the British laid a “mine barrage” between Britain and Norway and between Britain and France to cut off Germany’s access to the Atlantic. Later, the British Navy, the world’s largest, was joined by the U.S. Navy, the world’s second largest at the time, and the two allies made the mine barrage practically leak‑proof. Germany began to starve.

Mines in the mine barrage were all moored mines. Belligerents sometimes used drifting mines, but a loose mine is worse than a loose cannon. One can seldom accurately predict where winds and currents will take a drifting mine, so it is a danger to neutral and friendly shipping. A moored (or anchored) mine, like a drifting mine, has enough air in it to float, but it is attached to a sinker. As the sinker sinks, it pays out a previously determine length of cable. When the predetermined length is reached, the sinker’s cable drum locks, and the sinker pulls the mine down to a predetermined depth below the surface.

There are a variety of ways to detonate a mine. In World War I, the British used the Elia mine, which had a long lever attached to its side. If a ship struck the mine, it would probably move the lever, which would release a firing pin to strike the detonator. A more common mine, used by all belligerents in both world wars, relied on Hertz horns. The Hertz horn, a German invention, contained a glass vial with a bichromate solution. When the horn was crushed, the solution poured out of the broken vial and completed an electrical circuit that exploded the mine. A typical mine had Hertz horns protruding from all sides.

Some mines planted close to the shore have been detonated by electricity shot through a cable from the shore. This type, however, requires an observer to decide when an enemy ship is close enough to the mine, so it’s much less popular than mines that set themselves off. Magnetic mines were widely used in World War II. The ship’s magnetic field triggered the mine’s firing mechanism.

Because of magnetic mines, all steel naval ships in World War II were equipped with degaussing cables. These were cables run around the gunwales of the ship.

An electrical charge ran through the cables, neutralizing the ship’s magnetic field. “Limpet mines” used magnetism to attach themselves to the bottoms of ships. A United States model, intended to be attached by divers, had a plastic case and weighed only 10 pounds. It was attached by six magnets and had a timing mechanism that allowed divers to get away.

An Italian mine of this type looked like something devised for the Japanese Imperial Navy, the home of the kamikazes. It was a long torpedo, straddled by two divers. The divers would steer their subsurface craft up to an enemy ship, detach the large warhead below the enemy ship, set the timing mechanism, and get away as fast as they could.

The Italian “human torpedo” was designed to be launched by a submarine mother ship. Subs frequently laid mines, usually through their torpedo tubes.

Other mines were parachuted into the water from airplanes. Some of them had sinker mechanisms for mooring them. Others, especially magnetic mines or those set off by the noise of a ship’s engines, merely lay on the bottom of the sea. These were, of course, most useful in relatively shallow waters.

The mines Farragut encountered were defensive weapons. Almost all mines were defensive until World War II. In that war, though, the airplane and the submarine, particularly the former, allowed one country to mine an enemy’s harbors. Because the enemy had probably mined its own harbors, distinguish‑ing friendly from enemy mines complicated the minesweepers’ task.

Mines, unseen and almost undetectable, have added a spooky element to naval warfare that would have been utterly foreign to John Paul Jones.