Adventures of a Sea Hunter: In Search of Famous Shipwrecks

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.

Work on the submarine began in early 1864. On June 14, Kroehl wrote to the Navy’s Chief of the Bureau of Yards and Docks to press his case: “I sent you last week a pamphlet issued by the Pacific Pearl Company, for whom I am now building a submarine boat… In the operations against some of the rebel forts and harbors I have no doubt the Navy Department will require submarine boats, and I think it would be advisable to bring this to the attention of the Honorable Gideon Wells, and have the plans examined by a proper board.” The following day, he received a reply. The plans were interesting, and he should send them to the Secretary of the Navy. Kroehl did so, and on June 18, just four days later, was told by Secretary Welles to present his plans to W.W. Wood, the Chief Engineer of the United States Navy.

Sitting in a folder in the National Archives is Wood’s meticulous eighteen-page report on Kroehl’s submarine, written after he toured the vessel as it was being built in New York. Wood also drew up a large plan of the submarine — a sheet of paper that rolls out 3 feet — fully one-twelfth of the length of the actual craft. Reading the report and perusing the plan, it is obvious that the submarine on the beach at Isla San Telmo is the same vessel. The chamber on the top, according to Wood, was the “compressed air chamber… it has a semi-elliptic form and is built of two shells of best boiler iron % inch thick, the different pieces lapping 4 inches are double riveted with % inch countersink rivets, and braced with ribs of 3?” ? 3” ? ?” angle iron and 1 inch braces.” That kind of intricate detail is invaluable to an archeologist.

Wood’s report goes on to explain how a compressor inside the submarine was used to build up sufficient pressure to not only clear the upper ballast chamber to enable the submarine to rise but also to pressurize the hull to allow the unbolting of bottom plates so that the crew could reach into the water and harvest pearls — or to serve the purposes of war. This self-propelled “lock out” dive chamber — which many historians think is an innovation of the twentieth century — was designed and built in 1865. Wood’s report concluded by enthusing that “the uses to which a boat… in Naval Warfare, would be the removal of submerged obstructions in the channels of rivers and harbors. Approaching hostile fleets at anchor and destroying them by attaching torpedoes to their bottoms and exploding such localities as are commanded and covered by the guns of an enemy. The importance of a successful application of the principles involved in such a vessel for such purposes are of much importance and can not be too highly estimated.” Julius Kroehl couldn’t have said it better himself. It is a glowing endorsement, and I wonder what happened. Why didn’t the Navy buy the sub?

^{A section drawing of Sub Marine Explorer from the Journal of the American Society of Naval Engineers, 1902. James P. Delgado.}

Part of the answer is that the submarine was not yet finished. Another is that the war was winding down. Most of the major ports of the South had fallen, the Mississippi was secured and the collapse of the Confederacy was just a few months away. With the end of the war imminent, the Navy Department probably viewed Kroehl’s submarine, brilliant though it was, as coming a bit too late. A genius, yes, an engineering breakthrough, yes. But the time for such an invention to help “win the war” had passed.

And so the Union Navy, which had already invested much in the unfortunate sub Alligator, declined Kroehl’s offer. But there were still pearls to harvest in Panama, and the Pacific Pearl Company used Wood’s letter as an endorsement, publishing it in a promotional pamphlet to sell stocks in 1865. They mentioned it again in an article in the May 31, 1866, edition of the New York Times:

Yesterday afternoon there was a private trial of the Pacific Pearl Company’s Sub Marine Explorer, in the dock foot of North third-street, Eastern District… Julius H. Kroehl, engineer, with Frederick Michaels, August Getz and John Tanner, entered the explorer through her man-hole, which being finally dosed and the signal given the boat was submerged, and for an hour and a half she traversed the bed of the dock. During the submersion the friends of those onboard the boat exhibited considerable anxiety for their safety, but then at last when she rose to the surface… they gave vent to their feelings in repeated cheers. These were again and again repeated, when the engineer held up a pail of mud which he had gathered at the bottom of the dock, showing conclusively the success of the experiment.

But even if the end of the war had not ended the Navy’s interest in submarines, then the failure of its own great wartime experiment, the submarine Intelligent Whale, decisively closed the door. After three years of work, the shipyard finally launched Intelligent Whale just a month before Kroehl’s highly publicized demonstration of Sub Marine Explorer. Unlike Kroehl’s boat, Intelligent Whale was not a success, reportedly killing dozens of crewmen in various trials and tests. Renamed “Disastrous Jonah” by wags, Intelligent Whale ended her days laid up, unused. Thirty-one years would pass before the U.S. Navy acquired another submarine, in 1897. Another seventeen years would pass until a submarine again sank an enemy vessel in wartime, when the German U-21 sent HMS Kent to the bottom of the North Sea, an act that heralded the opening of a new and far deadlier campaign of submarine warfare and that changed the way war was fought at sea.

TO PANAMA AND OBLIVION

After the demonstrations of Kroehl’s submarine, both he and his invention left New York. Sometime that fall,