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Nasty little coal bombs.

In January 1864, Confederate President Jefferson Davis sat at his desk in the Richmond White House, admiring a new secret weapon. What resembled nothing more than a lump of coal was in fact a miniature torpedo, or mine. It had started out as a hollow iron casting, about 4 inches to a side, that was filled with gunpowder, then closed with an iron plug. After being dipped in a mixture of beeswax and pitch and covered in coal dust, it was ready to be smuggled into a coal pile or coaling station. When an unsuspecting stoker shoveled it into a Union steam-powered vessel’s firebox, it would explode, scattering burning coal across the ship’s wooden decks and rupturing its boilers.

Just how effective was this unlikely-looking weapon, dubbed the coal torpedo by Northerners? In the eyes of Federal commanders, it was a potentially devastating development. Union Admiral David D. Porter issued an order that anyone found with one should be “shot on the spot,” and General William T. Sherman wrote, “I would have no hesitation in authorizing steam-boat captains who find among their crews one or more such mischievous characters to drop them overboard and let them find the bottom in their own way.”

The coal torpedo was the invention of Thomas Edgeworth Courtenay, an insurance broker and entrepreneur. Born in Belfast, Ireland, in 1822, he sailed for America in 1842 on the packet Dumfriesshire, joining his two older brothers in New Orleans. By 1845, he had settled in St. Louis, where he became an agent for several insurance companies, joined the Masonic Lodge and befriended a range of prominent citizens, including Albert Pike, Sterling Price and many steamboat captains and pilots.

Courtenay made his first overture to the Confederate government in 1861, when he offered to serve as a purchasing agent in the West. In 1863 he received a volunteer commission as captain on the staff of one of his Missouri friends, General Price.

As an insurance broker, Courtenay knew quite well what damage could be done to a steamboat by a boiler explosion and fire. His first design consisted of firewood that had been bored out and filled with powder. The plan was to hide these altered logs in woodpiles, used for refueling boats along the rivers. In the course of the conflict, more than 70 steamboats were reportedly destroyed in this way on the Mississippi River by a band of saboteurs informally sanctioned by Confederate authorities and operating in and around St. Louis. James H. Baker, St. Louis’ Union provost marshal, listed Courtenay among them.

Courtenay soon realized that the real high-value targets—Union naval and military vessels—burned coal rather than wood. As a result, he set out to create a cast-iron coal bomb. But his plan required resources that were not available in Indian Territory, west of the Mississippi. He also needed the Confederate government’s official sanction if he hoped to be compensated under the terms of an 1862 bounty law that promised a reward to anyone who developed a new invention to attack Union shipping.

By October 1863, Courtenay had finished designing his coal bomb. He first approached President Davis about his invention in a letter of November 30, 1863, following up with a second letter on December 7 in which he outlined a plan for dispatching groups of men to plant his devices in various locations. Courtenay traveled to Richmond with recommendations from Sterling Price and General Albert Pike, who wrote, “The idea is novel but the means proposed are simple, efficacious, cheap and easily tested.” Courtenay’s weapon was endorsed by Davis and Secretary of War James Seddon. The Ordnance Bureau was directed to have castings made to facilitate his plan.

The shells were cast beginning in early 1864 at Richmond’s 7th Avenue Artillery workshop, across the street from the Tredegar Iron Works. One witness to their manufacture was Joseph Leuty, a British citizen who fled Richmond and was picked up by USS Jacob Bell on February 9, 1864. Leuty told Jacob Bell’s commander: “[F]or the last eight months I have been working in the artillery shop on Seventh street, Richmond, where they are now making a shell which looks exactly like a piece of coal, pieces of which were taken from a coal pile as patterns to imitate. I have made these shells myself. I believe these shells have power enough to burst any boiler. After they were thrown into a coal pile I could not tell the difference between them and coal myself.”

On January 19, 1864, Courtenay wrote to Colonel H.E. Clark, 7th Missouri Cavalry, that the castings were completed, and “the coal so perfect that the most critical eye could not detect it.” Adding that “the President thinks them perfect,” he noted Clark would have to use the wooden version of the weapon until arrangements could be made to send him some of the castings. As it turned out, distribution of the bombs was delayed until the Confederate Congress could pass secret legislation authorizing the formation of a secret service corps.

Secretary of War Seddon’s authorization, issued on March 9, 1864, limited use of coal shells to property of the federal government or property used by those forces, and stipulated reimbursement of 50 percent of the value of property damaged or destroyed, with compensation in Confederate bonds paying 4 percent. Private property of U.S. citizens on the seas and railroads was exempt unless that property had formerly been Confederate-owned. Courtenay was authorized to assemble a secret service corps not to exceed 25 men, who would be exempt from conscription, to distribute the torpedoes. He and his men were given broad authorization for travel within Confederate lines, and the Signal Corps was told to assist him.

Courtenay reportedly traveled in the James River area during the spring and summer of 1864, but it is not known how many of his coal torpedoes were successfully used against Union shipping. It’s also questionable whether he succeeded in sending some shells back to Clark and Price, for use in the Western Theater.

After Federal forces captured mail containing Courtenay’s name and plans, he left his torpedo project in the hands of associates and arranged to take 600 bales of cotton to England for the state of Alabama, with orders to purchase uniforms and supplies. He ran the blockade from Wilmington, N.C., to Halifax, Nova Scotia, in August 1864, bringing along some of his torpedoes for Confederate agents operating out of Canada. He carried a letter of introduction from Confederate Secretary of State Judah P. Benjamin to Jacob Thompson, Confederate Commissioner in Canada and head of the Rebel secret service in Toronto. Traveling with his family, Courtenay sailed from Halifax on September 30, 1864, arriving in Liverpool on October 13.

Three surviving examples of Courtenay’s coal torpedoes are known to exist. The manufacturing sample presented to Jefferson Davis was found in a cabinet in his office in the Richmond White House by Brig. Gen. Edward Ripley after the city fell to Union forces on April 3, 1865; it’s now at the Bennington Museum in Vermont. The other two are all that remain of a cache of coal shells, grenades and other weapons seized in 1865 by Toronto police from a house rented by Jacob Thompson. One of them measures approximately 4-by-4-by-3 inches and weighs 3.88 pounds, with walls three-eighths of an inch thick. The screw plug exactly matches the dimensions of the under-plug of a Bormann time fuze, and was probably machined on the same equipment. The shell can hold about 3.2 ounces of black powder. For comparison, a 6-pounder spherical case shot had a bursting charge of 2 ounces. By itself, a coal torpedo was not powerful enough to sink a ship. But since it was intended to explode under a boiler and scatter burning coal across the wooden decks of a steam-powered vessel, it had the potential to cause fires and secondary steam explosions that could seriously damage or even sink a ship.

The records of Confederate secret service activities were intentionally destroyed at the war’s end, making it impossible to list all the vessels damaged or destroyed by means of the coal torpedo. The best-documented instance is the burning and sinking of Maj. Gen. Benjamin Butler’s headquarters steamer Greyhound on November 28, 1864, a few miles below Bermuda Hundred on the James River. Butler, together with Admiral David D. Porter, escaped that mishap, but several of Butler’s prized horses perished.

Six months before that incident, on April 15, 1864, in New York Harbor, the boiler of the gunboat Chenango exploded, killing 23 men and burning or scalding dozens more. Gustavus V. Fox, assistant secretary of the Union Navy, wrote the next day that it had been blown up, “I fear by the coal shells prepared at Richmond and sent North….”

According to a newspaper clipping that Thomas Courtenay kept, the quartermaster steamer Missionary was damaged on the Tennessee River by one of Courtenay’s wooden torpedoes, and other examples of that weapon were found in the wood station used by the steamers.

In a November 24, 1864, letter to Lord Richard Grosvenor in London, Courtenay boasted: “By a very simple invention, I have been enabled to do much injury to Federal steam property & have proved (without a doubt) that iron-steel built steamers can be more easily destroyed than by cannon or conical shell—I have an independent corps who operate exclusively with my invention…they have destroyed many steamers on the Missi [sic] River & a few months ago blew up the new gunboat Chenango at Brooklyn, New York.”

On December 1, 1864, agents from Canada attempted to destroy the main building of the Springfield, Mass., Armory with a coal torpedo fitted with a time fuze. A watchman found the device under stairs, hidden under a piece of paper. It is the only documented attempt using the torpedoes against a building.

As the war ended, Courtenay met with other Confederate expatriates and tried to sell his torpedoes to the British, and also the Austrians, Italians and Spanish. None of those efforts came to fruition.

Courtenay eventually returned to the United States and the insurance business. He died in Jordan Springs, Va., on September 1, 1875. Although Courtenay never achieved widespread acclaim, his invention was among the ranks of Confederate wartime inventions that earned recognition by Union leaders. In 1886, for example, Admiral Porter wrote, “In devices for blowing up vessels, the Confederates were far ahead of us, putting Yankee ingenuity to shame.”

In fact, the weapon Courtenay invented did not fade from view. Throughout the last quarter of the 19th century his coal torpedo was still being mentioned in various forms in connection with insurance frauds. And during World War II explosives disguised as coal were developed by German, Japanese and American forces to sabotage factories, railroad locomotives and power plants. The simplicity of Courtenay’s original scheme was still evident 80 years later.


Joseph M. Thatcher, a fellow and past president of The Company of Military Historians, is a retired museum curator. Thomas H. Thatcher is a research assistant professor of medicine at the University of Rochester.

Originally published in the December 2011 issue of Civil War Times. To subscribe, click here.