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(above) A computer rendering of
H.L. Hunley
(right) Horace Lawson (H.L.) Hunley, inventor and builder of
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The Birth of Undersea Warfare – H.L. Hunley
by John Whipple

On April 19, 1861 – just days after the fall of Fort Sumter and the beginning of the American Civil War – President Abraham Lincoln ordered a naval blockade of all major southern ports in an effort to cut off Confederate weapons and supplies. Home to not only Fort Sumter but also the largest port in the south, Charleston, S.C. soon became the focus of the Union blockade, and the naval war itself. Nearly three years later, the blockade continued to maintain a near stranglehold on the city. The Confederates still held the city itself, but the situation was becoming dire as fewer and fewer supply ships broke through the massed Union forces.

It was in these desperate times that a steam-gauge manufacturer from New Orleans and a lawyer from Tennessee named Horace Lawson Hunley would join forces to support the South, and ultimately aid the beleaguered people of Charleston. Betting on technical ingenuity and sheer determination, these men led an effort to design, build, and send into battle what became the first submarine to sink a ship in wartime. Suffering many losses – including Hunley himself, for whom the vessel was later named – the success of the
H.L. Hunley garnered great attention from both Union and Confederate commanders. Although it was not an American Navy’s first submarine, Hunley was the first to indisputably prove the concept of undersea warfare, thus inspiring future generations of shipbuilders and redefining naval strategy forever.

With the Union’s blockading ships not only cutting off Southern supplies but also occasionally bombarding port cities all along the coast, the Confederate authorities were desperate for a means to strike back at the U.S. Navy’s dominating presence. They deployed explosive “torpedoes” – which today would be called mines – in many harbors to keep the ironclads and other enemy vessels at bay. However, what was really needed was some means to increase the success of their blockade runners. For that purpose, they endeavored to build a series of novel attack craft that could use torpedoes offensively and attack the blockade ships unseen.

Within the Confederacy, a spirit of both nationalism and the hope of financial gain fostered great interest in submersible design and construction in southern coastal cities, especially when high bounties were offered for sinking ships of the blockade. Unbridled by the inherent bureaucratic delays of U.S. Navy contracting, the Confederates encouraged a growing number of southern profiteers and ultimately enlisted approximately 50 for the Confederate cause.1 One of these men was James McClintock, who – with business partner Baxter Watson – had already sold the South two machines for making bullets. In closing their first deal to supply a combat submersible, they established the core design and engineering team that would, using trial and error, build a series of vessels that eventually culminated in the successful Hunley.2

Early Predecessors: Pioneer and American Diver

The first of a series of submarines designed and built by McClintock and Watson began construction late in 1861 in New Orleans. Fabricated from quarter-inch iron plates, Pioneer was 30 feet long and four feet in diameter, with dive planes and a propeller at one end powered by two crewmen working a hand crank. Although McClintock himself later admitted that the overall configuration was faulty, the submarine reportedly sank a schooner and two target barges during sea trials by means of towed torpedoes. Despite its purported successes, Pioneer never saw battle because of the untimely fall of New Orleans to Union forces under Capt. David G. Farragut and General Benjamin F. Butler in late April 1962. McClintock and his team were forced to scuttle the vessel in Lake Ponchartrain and flee to Mobile, Ala. Pioneer was later recovered and studied by the Union, and in 1868 it was sold for scrap at a public auction. Nonetheless, their successes with Pioneer – and their narrow escape from New Orleans – drove these men to make a second attempt at perfecting their craft.3

It was early in the construction of Pioneer that Horace Hunley joined McClintock and Watson in their efforts, ultimately providing significant financial backing for the craft and several others they would build together. Although he had already been a state legislator, customs collector, and southern planter, it would be for his role as a submarine pioneer that Hunley would be remembered.

In Mobile, McClintock and his team were quick to find new business partners in the wake of the loss of Pioneer. In Thomas Park and Thomas Lyons, who owned the Park & Lyons machine shop, McClintock found both new support and a venue to build his second undersea vessel, the American Diver.

Having learned much in building Pioneer, McClintock pursued new ideas – and faced some old challenges – in his second effort. After the war had ended, he noted these thoughts about the design of American Diver.

“To obtain room for the machinery and persons, she was built 36 feet long, three feet wide, and four feet high; 12 feet at each end was built tapering or modeled to make her easy to pass through the water. There was much time and money loss in efforts to build an electromagnetic engine for propelling the boat… I afterwards fitted cranks to turn the propeller by hand, working four men at a time, but the air being so closed, and the work so hard, that we were unable to get a speed sufficient to make the boat of service against vessels blockading the port.” 4

Little is know of McClintock’s electromagnetic engine beyond the fact that he eventually abandoned the idea, but it reveals the magnitude of his technical creativity in addressing the challenges of underwater propulsion. He and his team had also made a similarly abortive effort to use a small, custom-built steam engine to propel American Diver before finally returning to human labor. Just as with Pioneer, American Diver was fabricated from quarter-inch iron. Its sides were squared off, in contrast to the first vessel, and it had a 30-inch propeller in the stern. 5

In February of 1863, American Diver was taken in tow for Fort Morgan, at the mouth of Mobile Bay, with the intention of attacking the blockading ships. Unfortunately, foul weather set in during the transit, and Diver was swamped. It was ultimately cut free and allowed to sink for fear of taking its towing ship down with it. No lives were lost, but to this day American Diver still sits somewhere on the sea floor where it went down.

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Two views of H.L. Hunley drawn from a description by Charles Hasker, a survivor of an early sinking.

The Union Takes Notice

By this stage in the war, the South had attempted to deploy three general classes of offensive platforms – essentially torpedo delivery vessels. In addition to slightly modified traditional surface craft, there were also a number of steam-powered semi-submersible vessels known as “David” boats. In October, 1863, a David successfully attacked USS New Ironsides, a blockading ironclad, drawing significant attention from Union flag officers. Just as concerns were growing over the appearance of these Davids, Union officers also began receiving reports of the third type of torpedo craft, and news of this hand-powered, fully submersible vessel – a David that could dive – had them even more uneasy.6

Rear Adm. John Dahlgren, commander of the South Atlantic Blockading Squadron, in reporting back to Gideon Welles, Secretary of the Navy, wrote of these events.

“The action of the ‘Davids’ has been, of course, pretty well exemplified on the Ironsides’; that of the ‘Diver’ is different, as it is intended to submerge completely, get under the bottom, attach the torpedo, haul off, and pull trigger. So far the trials have been unlucky… Still she does dive, as one of the deserters saw her pass twice under the bottom of a vessel he was in and once under the Charleston. … On receiving this intelligence I caused additional means of prevention to be used, as will be seen by copies of enclosed orders, and the Department may be assured that if any of our monitors are injured it will not be for lack of the utmost vigilance.” 7

Clearly the admiral was wary. To add to the protection of his vessels, underwater nets were deployed, and steam tugs, scout boats, and cutters were used as pickets in advance of and around the blockading ships.

Apparently, the “Diver” in Admiral Dahlgren’s report was actually H.L. Hunley – McClintock’s third submarine – which had been observed conducting trials prior to her fateful mission.

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A computer rendering of
H.L. Hunley and sinking USS Housatonic.

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