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1. The Connecticut Water Machine Versus The Royal Navy

July 2024
15min read

Shortly after a midnight in early September of 1776, a strange little convoy set out from South Ferry Landing at the southern tip of beleaguered Manhattan Island on a mission unique in Revolutionary War history, indeed, in world history. Two whaleboats towed between them an odd craft which, riding nearly awash, carried a crew of one—a young sergeant of the Connecticut Militia. To the rasp of oars in thole pins, the tow headed south toward Staten Island and The Narrows, nearly five miles distant, where a host of lights marked a British armada riding serenely at anchor.

Without any naval opposition, these ships ranged the East and Hudson rivers, greatly increasing General Howe’s mobility as he tightened the noose around the Continental Army, now isolated on Manhattan foDowing the defeat on Long Island. From Brooklyn to Hell Gate, the British were poising for a strike across the East River. An American victory, however small, was sorely needed to boost morale. The man who hoped to engineer this victory—a slightly built, somberly clad civilian—paced anxiously at South Ferry Landing as the little convoy slid off into the night.

In less than an hour, the stern lanthorns on the nearest ships were clearly visible, even the faint golden wakes they cast on the water. The rowers rested on their oars while the sergeant drifted up between his escorts. After a brief, murmured exchange, the towlines were cast off and the whaleboats turned back toward Manhattan. Now drifting alone, the sergeant prepared to move the Connecticut Water Machine against the British.

The evolution of the sergeant’s strange craft literally began with a bang when, in 1772, David Bushnell, a brilliant mathematics student at Yale, successfully exploded two ounces of gunpowder in a submerged wooden pipe “to prove to some of the first personages in Connecticut that powder would take fire under water.” His experiment was revolutionary for, although marine petards had been devised over a century before, they were surface craft with gunpowder cargo, intended to damage ships at or above the waterline. Bushnell later demonstrated the destructive force of underwater explosion by placing two pounds of gunpowder in a wooden bottle that was piped upward through a two-inch oak plank surmounted by a hogshead stone-weighted to sink nearly awash. “A match put to the priming exploded the powder,” the inventor reported, “rending the plank … demolishing the hogshead, and casting the stones and the ruins … with a body of water, many feet into the air, to the astonishment of the spectators.”

Born to a struggling farm family near Saybrook, Connecticut, David Bushnell was twenty-eight years old before settlement of his modest inheritance permitted him to enter college. A fervent Whig, he participated in the campus movement for colonists’ rights and numbered Nathan Hale among his friends. Sensing military application of his experiments should war come, he had, by 1774, begun to draft plans for a “submarine mine, or torpedo.”

A stout log was to be hewn to an egg shape, then sliced longitudinally, the two halves being hollowed out to accommodate 150 pounds of gunpowder and the detonator—a clockwork that would trigger a flintlock after a preset interval of up to eight hours. Bound together by iron hoops, the completed “egg” would then be waterproofed by tarring.

Satisfied that this mine would sink any ship afloat, Bushnell next pondered how to attach it to a target’s hull. Going alongside an enemy ship by small boat, even at night, was risky. Furthermore, for maximum concussive effect, the mine should explode below the waterline. Ideally, then, the target should be approached, and the mine affixed, underwater. Intrigued, he began to ponder the practicality of this novel proposition.

The concept of a submarine did not spring full-blown from David Bushnell, for man had been intrigued by the idea of underwater craft for nearly two centuries. In 1575 a British naval officer named William Bourne designed, but never built, a boat with a wooden framework raised above the gunwales and covered with waterproofed leather. To submerge, the vessel’s volume was to be decreased by tightening hand vises that contracted the leather covering, while to ascend, volume was restored to normal by relaxing the vises. Such a boat was in fact launched in 1605 and promptly lost when the restored buoyancy of the leather was not enough to break the suction of the muddy river bottom. The first moderately successful underwater craft—that of the Dutch physician Cornells Drebbel- resembled its predecessor, with oars protruding through waterproof leather flaps for propulsion. In 1620 it submerged fifteen feet in the Thames River, maneuvered, and returned to the surface.

To what extent Bushnell was acquainted with any of these earlier designs is unknown. But it was he alone that first made the submarine a practical reality and a potential naval weapon.

By winter vacation, 1774, his efforts had begun to coalesce into plans for an underwater mine-delivery vehicle, or “Sub-Marine Vessel,” as he termed it. And with the start of war at Lexington and Concord on April 19,1775, he hurried back to Saybrook, eager to complete these plans now that enemy hulls were no longer a theoretical abstraction.

To avoid gossip reaching the British, Bushnell had his submarine built in a shed on secluded Poverty Island in the Connecticut River, not far from Saybrook. He bruited it about that he was going into fishing and that the shed would serve as a small boatyard. Thus, no suspicions were aroused as the strange craft began to take shape.

The submarine’s built-up oak hull was iron-hooped, calked, and tarred all over. A hinged brass hatch cover with three doors and six tiny windows closed the top. A foot-operated valve would admit seawater into the ballast tank, a brass force pump would eject it. The two horizontal propellers could be cranked either by hand or foot-treadle, or both. Once submerged equilibrium was attained, a hand-cranked vertical propeller would move the boat up or down. Air intake and exhaust pipes through the hatch cover terminated in snorkel-type valves that were designed to close automatically upon submerging.

Its weapon system was a hand-cranked, detachable wood screw joined by a rope to an oaken mine which was piggybacked on the boat, held by a long screw. Once under an enemy hull, the operator was to thrust upward on the vertical crank to start the screw, turn the crank to bury it, then detach it from the submarine by unscrewing a long bolt that ran up through the crankshaft. He then backed off the screw piggybacking the mine, thus automatically starting the clockwork fuse as the mine bobbed up along the hull to its tether. After a preset interval to allow the submarine’s escape, the clockwork unpinned a flintlock, which fired the 150 pounds of black powder.

Late in the summer of 1775, the completed submersible, now nicknamed the Turtle , was hoisted aboard a sloop and taken downriver to Long Island Sound for testing. David Bushnell himself took the Turtle down the first time. Laboring in the candlelit interior, he verified propulsion, descent by ballast intake and ascent by ballast pumping. He surfaced after about twenty minutes, generally pleased, but utterly exhausted. From this day on, his brother Ezra would be the Turtle ’s operator.

The test had disclosed two problems. Steering by two propellers was erratic and cumbersome, so Bushnell removed the one athwartships and installed a rudder controlled by a tiller with considerable leverage, which would allow the craft to be sculled. He then addressed the graver difficulty: how to increase the time of submergence by eliminating the candle. From his days on the family farm, he recalled the curious glow of fox fire—decaying wood that hosts a luminous fungus. Dismantling the craft’s depth gauge, he inserted into the glass tube a cork to which a bit of fox fire had been affixed, wired pieces of fox fire to the indicating marks on the gauge support bar, and put flecks of the stuff on his compass card.

Remarkably enough, Bushnell had financed this complex engine of war, which had no imaginable peacetime application, out of his own pocket. Pointing to the Turtle ’s demonstrated success, Dr. Benjamin Gale, one of Bushnell’s few confidantes and himself an inventor, urged him to apply for aid to the Connecticut Council of Safety. CaIe also asked permission to write news of the development to the influential Benjamin Franklin. His letter brought prompt results: Franklin stopped to inspect the submersible on October 18, 1775, while en route to Cambridge for a conference with General Washington.

Since late summer, Ezra Bushnell had been practicing in the refitted Turtle , learning its idiosyncracies and mastering the considerable skills of diving and navigating under the guidance of luminous blurs. Shortly after Franklin’s visit, he demonstrated his proficiency by conducting a mock attack on an old hulk, approaching it, submerging, affixing the wood screw, releasing the mine, and escaping handily before the derelict was blown to flinders. Dissatisfied by the slowness of ascent with one force pump, Bushnell installed a second. With this modification, the submarine was now ready for action against real targets—the British ships at Boston.

British intelligence had by now begun to receive reports about the “famous Connecticut Water Machine.” Dr. Gale himself was unwittingly feeding the espionage network via the postmaster at Killingworth, a silent Tory who was opening Gale’s letters before sending them on, and informing William Tryon, the former Royal Governor of New York, of their contents. Tryon’s dispatch to Vice-Admiral Shuldam at Boston was startlingly accurate, advising that when Bushnell had gotten a pump of new construction Shuldham might expect to see his ships in smoke. Skeptical, the vice-admiral made no attempt to seize Bushnell.

Tryon’s dire prediction might indeed have come true had not the British found a silent ally in the winter weather. To his chagrin, Bushnell found that fox fire lost its luminescent property when frozen.

The return of warmer weather solved the fox-fire problem, but now the British, under the guns of Henry Knox’s artillery on Dorchester Heights, found their position in Boston untenable. On March 17, 1776, they evacuated the port, sailing off to Halifax to refit and await reinforcements. Losing these targets just as he was at last ready to move against them must have set Bushnell’s teeth on edge. But new ones shortly would be forthcoming.

The British squadron reappeared off New York City on June 29, and nine thousand regulars took Staten Island unopposed and set up camp. Periodically that summer, more British ships arrived, notably Admiral Richard Howe’s fleet, carrying the first contingent of mercenaries. By August 12, Staten Island bulged with thirty-two thousand British and Hessians.

To counter this threat, Washington moved his army of twenty thousand men south from Boston, disposing his left flank on Long Island, where he fortified Brooklyn Heights. His center was on Manhattan Island: General Israel Putnam with five thousand men near the southern tip, and Fort Washington in the north. His right was Fort Lee on the Jersey Palisades, facing Fort Washington across the Hudson. But as British naval superiority became overwhelming—ten ships of the line, twenty frigates, and hundreds of transports—Washington’s position became shaky. On July. 12 two British frigates ran the thunderous gauntlet between Forts Washington and Lee, anchoring far upriver at Tarrytown, thus demonstrating the ease with which the British could range around Manhattan Island.

Meanwhile, David and Ezra Bushnell had transported the Turtle to the vicinity of the embattled city. No less an aide of Putnam’s than Aaron Burr inspected the strange craft and reported back favorably. The doughty general welcomed the chance to shake powder from British wigs by blowing up a ship or two, but ensuing preparations for an attack on the man-of-war Asia were thwarted when once again the enemy found a natural ally: in mid-August the submarine’s only operator, Ezra Bushnell, came down with typhoid fever.

Shaken but determined, David Bushnell cast about for volunteers to take Ezra’s place. General Samuel Parsons of the Connecticut Militia found three willing men, among them the twenty-seven-year-old Sergeant Ezra Lee. The Turtle and these recruits were taken up Long Island Sound to the relative safety of Saybrook, where Bushnell tried in a few days to cram into the three what it had taken brother Ezra several months to learn.

In the middle of this brief training period, the British invaded Long Island and roundly beat the Americans. Hearing of the defeat, Bushnell terminated the training, loaded the Turtle and, with his volunteers, sailed south from Saybrook. With his craft off-loaded at South Ferry Landing, David Bushnell conferred with the military, including General Putnam, pointing out the need for slack water and calm. Within several days of the Turtle ’s arrival, these ideal conditions seemed at hand. “It was determined,” wrote Bushnell, “to make an experiment with this machine in the night, on the ship Eagle , of sixty-four guns, on board of which Admiral Lord Howe commanded.” Bushnell selected Sergeant Ezra Lee for the mission because he “appeared more expert than the rest.…”

As the whaleboats that had towed him down from South Ferry Landing dissolved into the darkness, Lee was startled to find himself not in the anticipated slack water but in an ebb tide that was sweeping him down toward The Narrows, away from his target.

For the next several hours he sweated in the humid, tar-reeking darkness, laboring at crank and treadle, first to stay his drift, then to regain his original position. Through the forward door, he could see the Eagle now, not a half-mile distant across the pewtery chop. Dropping back to the thwart, he began to crank with renewed vigor. In another hour, the sun would be up and it would be too late.

Rising frequently to check his progress, he edged closer and closer. Now he could see British crewmen on deck, hear their voices, make out the carvings on the warship’s stern. As he drifted in near her, Lee buttoned up the hatch cover, dropped to the thwart and tramped the intake valve. Darkness poured down as seawater gurgled aboard beneath him. Ten feet … fifteen … the luminous cork rose in the depth gauge.

Releasing the intake valve, he pumped the tiller, sculling ahead cautiously until he felt the Turtle jar gently against the Eagle ’s hull. He grasped the wood screw and thrust upward sharply. There was no resistance to his cranking. Had he bounded off? A few turns of the vertical propeller brought a series of bumps on the hatch cover as the Turtle rose against the hull. He tried the wood screw again. Still no bite. Pumping ballast to increase upward pressure, he tried once more with no success.

Sculling gingerly, he moved to another spot under the hull. Then, without warning, the Turtle tilted sharply and lunged upward. Lee grabbed for support. Light burst in at the small windows as, surfacing, she leaped, then sank back heavily. Thrusting to his feet, he pressed his face to one of the windows. Blurry but unmistakable, the Eagle was only a few feet away.

Years later, Ezra Lee was to write of this moment: “I hove about to try again but on further thought I gave out, knowing that as soon as it was light the ships’ boats would be rowing in all directions, and I thought the best generalship was to retreat as fast as I could as I had four miles to go before passing Governors Island.”

His retreat was not without peril. “I jogg’d on as fast as I could, and my compass being then no use to me, I was obliged to rise up every few minutes to see that I sailed in the right direction, and for this purpose keeping the machine on the surface of the water and the doors open, I was much afraid of getting aground on the island, as the tide of the flood set on the north point.”

The brass hatch cover, glinting in the rising sun as it zigzagged north, was sighted from British-occupied Governors Island, and soon drew hundreds of curious to the parapets. To Lee’s dismay ”… a number came down to the shore, shoved off a twelve oar’d barge with five or six sitters and pulled for me.”

Choosing not to submerge and proceed by compass, he freed the wood screw and, as the barge closed to sixty yards, released the magazine “in hopes that if they should take me they would likewise pick up the magazine and then we should all be blown up together.” This tactic succeeded beyond his hope: after a wary reconnaissance of the floating mine, the crew opted for discretion and fled.

Weathering the island, Lee was sighted from South Ferry Landing and a whaleboat came out to tow him to safety. Twenty minutes later, as he was briefing Bushnell and General Putnam, the magazine, having drifted into the East River, “went off with a tremendous explosion, throwing up large bodies of water to an immense height.” To Lee’s assertion that the wood screw must have struck an iron strap securing one of the gudgeons supporting the Eagle’s rudder, Bushnell was to write later: “Had he moved a few inches, which he might have done without rowing, I have no doubt but he would have found wood where he might have fixed the screw; or, if the ship were sheathed with copper, he might easily have pierced it.” Lee’s brief training was simply unequal to the precise manipulation of controls this required. The attack had failed, Bushnell concluded, because the sergeant was “not well-skilled in the management of the vessel.”

On September 12, eyeing the British build-up on Long Island opposite Kip’s Bay on Manhattan, Washington began evacuating supplies. Bushnell and the Turtle were slooped up the Hudson to Fort Washington. On September 14 the British swarmed across the East River, overran the American positions at Kip’s Bay, but allowed Putnam’s troops to escape north to Harlem Heights, where Washington was reforming his troops in a strong defensive position.

Not long after, British frigates beat up river, anchoring near Fort Washington. When a fireship attack on them failed, Bushnell sent out Sergeant Lee and the Turtle . Thirty-nine years later, Lee wrote of this attempt: “My intention was to have gone under the ship’s stern and screwed on the magazine close to the water’s edge, but I was discovered by the watch, and was obliged to abandon this scheme; then shutting my doors I dove under her, but my cork in the tube … got obstructed and deceived me, and I descended too deep and did not touch the ship; I then left her.”

Bushnell’s account, written in 1787, differed significantly: “In going towards the ship, he lost sight of her and went a great distance beyond her; when he at length found her, the tide was so strong that as he descended under water for the ship’s bottom—it swept him away.” Evidently, the attack had been correctly timed to occur at slack water, unlike the attempt on the Eagle . Thus Lee’s faulty navigation was at least partly responsible for its failure.

One of the other volunteers subsequently mounted a third attack, which failed utterly. Perhaps stung by these harassments, the British frigates hauled anchor on October 9 and headed upriver. The Turtle was at this time aboard a sloop which lay in company with four galleys, two stone ships and a schooner. This little fleet fled up the Hudson as the frigates ran the fire of the shore batteries. In the pursuit, a ball from one of the men-of-war holed the sloop. It sank promptly, carrying the Turtle with it and forcing Bushnell’s cadre to swim ashore.

“Though I afterwards recovered the vessel,” wrote the luckless inventor, “I found it impossible at that time to prosecute the design any farther. I had been in a bad state of health from the beginning of my undertaking … I despaired of obtaining the public attention and the assistance necessary. Besides, I found it absolutely necessary that the operators should acquire more skill in the management of the vessel before I could expect success: which would have taken up some time and made no small additional expense. I therefore gave over the pursuit for that time, and waited for a more favorable opportunity, which never arrived.”

Having disbanded his little private navy and disposed of the Turtle in a manner that remains a mystery to this day, David Bushnell concentrated on improving his mines. That winter, he added ratcheted wheels protruding from the case, any rotation of which detonated the explosive. On August 13, 1777, he and two others launched from a whaleboat two of these mines joined by a six-hundred-yard line, intending them to float down upon and enwrap the British warship Cerberus , which, in company with a schooner, had anchored in Long Island Sound above Saybrook some days earlier. Both ships sighted the mines and started independently to haul bights of the line aboard. The schooner unluckily got the mine at its end aboard first. Curiosity about the ratchet wheels did the rest. With fine disregard for the three dead crewmen and demolished schooner, Commodore Symons of the Cerberus reported to Sir Peter Parker: “There is no knowing what damage it might have done.”

Having at last drawn blood, Bushnell next replaced the ratchet wheels with spring locks and weighted the mine so that it would lurk underwater, suspended by a tether from an innocuous floating keg. Then, shortly after Christmas, 1777, he launched a squadron of these mines into the Delaware River at Bordentown, New Jersey, twenty-six miles above the British ships at anchor in Philadelphia. The scheme—to float an inescapable mass of mines down onto the ships—today seems remarkably ill conceived. Set adrift much too far above Philadelphia, the flotilla was delayed and dispersed by ice, not straggling into the city until January 5, 1778. Two curious boys were first killed investigating the kegs. Shortly afterward, the crew of a barge suffered the same fate. Alerted by these explosions upriver, the British ships opened fire on the advancing kegs, the bombardment later celebrated in satirical verse by Francis Hopkinson as “The Battle of the Kegs.”

Disgruntled but undiscouraged, David Bushnell labored on with his mines until, on May 6,1779, he was captured near Norwalk, Connecticut, by Tory raiders bent on bigger game. So little known was he that General Putnam, writing to Washington of this raid, concluded: “As the last mentioned gentleman, who was there in the prosecution of his unremitted endeavours to destroy the enemy’s shipping is personally known to very few people, it is possible that he may not be discovered by his real name or character, and may be considered of less consequence than he actually is.” This was precisely the case, for on May 13, Putnam exchanged nine Americans, including Bushnell, for British prisoners. The “ingenious Dr. Bushnell,” as Putnam termed him, thus slipped unidentified through British fingers.

That August, Bushnell, now severely straitened financially, accepted a commission as captain-lieutenant in the newly formed Corps of Engineers and Sappers of the Continental Army. Serving honorably but with little opportunity for inventiveness, he returned to civilian life in December, 1783, when the army disbanded.

Now forty-one, Bushnell returned to Saybrook, eventually petitioning the Connecticut General Assembly for £489 expended on the Turtle and his mines. That body granted him just £150. In 1785 he suffered an illness that lingered for two years, during which Thomas Jefferson, then minister plenipotentiary at Paris, wrote to George Washington requesting that ”… you be so kind as to communicate to me what you can recollect of Bushnell’s experiments in submarine navigation… .” Jefferson was trying to have Bushnell recognized as the inventor of the screw propeller, which a Frenchman was currently seeking to patent. Washington’s reply was curious: “Although I wanted faith myself, I furnished him with money and other aids to carry his plan into execution … I then thought and still think that it was an effort of genius.” By October, 1787, Bushnell was able to post a letter to Jefferson containing his “General Principles and Construction of a Sub-Marine Vessel” and a description of the operations of the Turtle around New York City. This done, he ordered his affairs, quietly departed Saybrook in December, and simply vanished.

Forty-one years later, in February, 1826, a highly respected teacher and civic-minded citizen—one David Bush—died in Columbia County, Georgia. His personal effects yielded up models of “some curious machinery, partly built,” correspondence with the Secretary of Navy relating to an improved underwater torpedo, and a will directing a search for Ezra Bushnell’s children in Saybrook as his rightful heirs. (They were found.)

Just fifty-one years after he had slipped below the surface of Long Island Sound to test his “famous Connecticut Water Machine,” David Bushnell slipped from this earth, quietly, as little known in death as he had been in life.

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