War spurs terrible and magnificent inventions, often taking ideas and concepts developed in peacetime and testing them hurriedly in times of crisis. During the Civil War, technology played a significant role. Among other innovations, the war introduced new guns and more powerful cannon, ironclad warships with rotating turrets, undersea mines — and the submarine. There was nothing new about each of these inventions save their first practical and deadly use in combat. The pioneering naval accomplishments of the war started with the attack on the wooden fleet of the Union Navy at Hampton Roads, Virginia, by the Confederate ironclad CSS Virginia, demonstrating that this new type of warship doomed the “wooden walls” that had dominated naval warfare for centuries. The first clash between ironclads took place when the Union’s USS Monitor interceded between Virginia and the Union wooden fleet the following day and fought the Confederate ship to a standstill.
Another innovation was the use of an electrically detonated “torpedo,” or mine, one of which sent the Union’s ironclad Cairo to the bottom of the Yazoo River, giving the ill-fated gunboat the dubious distinction of being the first warship in history to be sunk by a mine. Later, there was the brave but doomed sortie of the Confederate submarine H.I. Hunley into Charleston Harbor to sink the Union warship Housatonic with a spar-mounted “torpedo” projecting from her bow. Shortly after this victory, Hunley sank, taking her crew with her, just a few hundred yards from her victim. No one knows why Hunley sank, but the tiny craft gained fame as the first submarine to destroy an enemy vessel in combat. Quickly buried by silt, Hunley’’s grave remained undiscovered for 150 years.
As for submarines, both sides embraced this new technology. Inventors proposed various underwater craft and built some that operated with various levels of success, killing their builders and crews on more than one occasion. A number of projects were launched, some in secrecy, others more publicly, leaving behind an unfortunately incomplete record of pioneer submarines and submariners. But the rediscovery of Julius Kroehl’s Sub Marine Explorer and a slow unraveling of his wartime career, buried in the National Archives, suggests that at every step of the way, as the Confederates developed both their “torpedoes” and submarines, Kroehl was there to develop something to counter them for the Union side. It may well be one of the last great untold stories of the Civil War.
Julius Kroehl was a German-born immigrant who came to America in 1838. He studied to become an engineer, and in 1845 he won a U.S patent for a flange-bending machine for ironwork. In 1856, he was well enough established to win a contract from New York City to build a cast-iron “fire watch tower” in Manhattan’s Mount Morris (now Marcus Garvey) Park. In an age before fire alarm boxes, volunteer fire fighters watched the city from towers, ringing a bell to sound the alarm.
But Kroehl’s real interests lay underwater. At the same time that he was engaged in his fire tower project, Kroehl and his business partner, Peter Husted, were contracted by the City of New York to remove part of Diamond Reef, near Governor’s Island in the East River, as it was a hazard to navigation. According to the Scientific American of August 5, 1856, “Messrs. Husted & Kroehl” were blasting to remove 6 feet of depth on the 300-foot reef. “Large tin canisters attached to the lower ends of strong pointed stakes, are sunk to rest on the face of the reef, and are discharged with a galvanic battery.” It was on this job that Kroehl became interested in diving. In 1858, Husted and Kroehl hired a new partner, Van Buren Ryerson, who had just built a pressurized diving bell that he called Submarine Explorer. Eight years later, Kroehl used the basic principle of Ryerson’s bell to build the world’s most sophisticated submarine.
With the outbreak of Civil War in April 1861, Julius Kroehl was the first inventor to write to the U.S. Navy to offer a submarine that could be used to enter Southern ports and destroy “obstacles” from below. His “cigar-shaped” design was not adopted, as the Union Navy ended up with another submarine, courtesy of a daring demonstration by French inventor Brutus de Villeroi, who had built a 32-foot submersible and tested it on the Delaware River. Chased by the harbor police and captured when it ran aground, de Villeroi’s submarine attracted the attention of the press and the Navy, which ended up buying it and commissioning it as USS Alligator. Never successful and plagued by problems, the tiny craft ended up being cast adrift off Cape Hatteras in a storm on April 2, 1863, and was lost.
Meanwhile, Julius Kroehl, his proposal for a submarine rejected, joined the war effort as an expert in underwater explosives. He worked to clear the way for the Union assault up the Mississippi River, which the Confederates had blocked. On the night of April 10, 1862, “Mr. Kroehl went with a party in two boats to make a close reconnaissance of the hulks, rafts and chains below the forts. On the strength of his report plans were made by Admiral Porter and him for the destruction of the obstructions.” Unfortunately, the attempt, made with electrically detonated charges, was “not completely successful,” but the Union fleet did successfully navigate the river.
In recognition of this and other efforts, the Navy promoted Kroehl to Acting Volunteer Lieutenant and in January 1863 assigned him to remove the Confederate rafts blocking the Yazoo and Red rivers. Just then, Kroehl heard that a Confederate “torpedo” had sunk the ironclad gunboat Cairo on the Yazoo. Ironically, the commander of Cairo, Thomas Oliver Selfridge, had served as captain of the ill-fated submarine Alligator. A colleague sarcastically noted that Selfridge “found two torpedoes and removed them by placing his vessel over them.”
A month after the fall of Vicksburg on July 4, 1863, Kroehl was discharged with malaria. During his convalescence, he planned a submarine that could descend into the water and there, on the bottom, send out a diver to disarm torpedoes and set charges of his own, beyond the reach of Confederate guns. His submarine would be a perfect counter to the South’s own program of underwater warfare. Kroehl needed backers and money to build his sub, knowing full well from experience that the Navy would not accept plans alone and authorize funds to build an experimental craft. He found his backers in the Pacific Pearl Company, which was interested in exploiting the pearl beds off Panama.
“Discovered” by Spanish conquistadors who seized examples from the natives of the isthmus in the early sixteenth century, Panama’s pearls had been the source of many fortunes in the succeeding centuries. But as divers cleaned out the shallower beds, that left only the ones in deeper water. Using a submarine was one way to tap into the hitherto inaccessible riches in the sea off Panama. Kroehl appealed, doubtless, more to the profit motive of his employers than to their patriotism. If the Navy wouldn’t buy the submarine, they could always take it to Panama and use it to rake up pearls off the seabed.