The American Journal of Science/Series 1, Volume 2/Submarine Navigation

by Charles Griswold

PHYSICS, MECHANICS, CHEMISTRY, AND THE ARTS.

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SUBMARINE NAVIGATION.

Art. IX.   Description of a Machine, invented and constructed by David Bushnell, a native of Saybrook, at the commencement of the American revolutionary war, for the purpose of submarine navigation, and for the destruction of ships of war; with an account of the first attempt with it, in August 1776, by Ezra Lee, a sergeant in the American army, to destroy some of the British ships then lying at New-York.  Communicated by Charles Griswold, Esq.

TO PROFESSOR SILLIMAN.

Lyme, Conn. Feb. 21st. 1820.

Sir.

IT  is to be presumed that every person who has paid any attention to the mechanical inventions of this country, or has looked over the history of her revolutionary war, has heard of the machine invented by David Bushnell, for submarine navigation, and the destruction of hostile shipping.  I have thought that a correct and full account of that novel and original invention, would not be unacceptable to the public, and particularly to those devoted to the pursuit of science and the arts.

If the idea of submarine warfare had ever occurred to any one, before the epoch of Bushnell's invention, yet it may be safely stated, that no ideas but his own ever came to any practical results.   To him, I believe, the whole merit of this invention is unanimously agreed to belong.

But such an account as I have mentioned, must derive an additional value, and an increased interest from the fact, that all the information contained in the following pages, has been received from the only person in existence possessed of that information, and who was the very same that first embarked in this novel and perilous navigation.

Mr. Ezra Lee, first a sergeant and afterwards an ensign in the revolutionary army, a respectable, worthy, and elderly citizen of this town, is the person to whom I have alluded; to him was committed the first essay for destroying a hostile ship by submarine explosion, and upon his statements an implicit reliance may be placed.

Considering Bushnell's machine as the first of its kind, I think it will be pronounced to be remarkably complete throughout in its construction, and that such an invention furnishes evidence of those resources and creative powers, which must rank him as a mechanical genius of the first order.

I shall first attend to a description of this machine, and afterwards to a relation of the enterprise in it by sergeant Lee; confining myself in each case, strictly to the facts with which he has supplied me.

Yours, &c.
CHARLES GRISWOLD,

Bushnell's machine was composed of several pieces of large oak timber, scooped out and fitted together, and its shape my informer compares to that of a round clam.   It was bound around thoroughly with iron bands, the seams were corked, and the whole was smeared over with tar, so as to prevent the possibility of the admission of water to the inside.

It was of a capacity to contain one engineer, who might stand or sit, and enjoy sufficient elbow room for its proper management.

The top or head was made of a metallic composition, exactly suited to its body, so as to be water-tight; this opened upon hinges, and formed the entrance to the machine.   Six small pieces of thick glass were inserted in this head, for the admission of light: in a clear day and clear sea-water, says my informer, he could see to read at the depth of three fathoms.  To keep it upright and properly balanced, seven hundred pounds of lead were fastened to its bottom, two hundred pounds of which were so contrived as to be discharged at any moment, to increase the buoyancy of the machine.

But to enable the navigator when under water, to rise or sink at pleasure, there were two forcing pumps, by which water could be pressed out at the bottom; and also a spring, by applying the foot to which, a passage was formed for the admission of water.   If the pumps should get deranged, then resort was had to letting off the lead ballast from the bottom.

The navigator steered by a rudder, the tiller of which passed through the back of the machine at a water joint, and in one side was fixed a small pocket compass, with two pieces of shining wood, (sometimes called foxfire,) crossed upon its north point, and a single piece upon the last point.   In the night, when no light entered through the head, this compass thus lighted, was all that served to guide the helmsman in his course.

The ingenious inventor also provided a method for determining the depth of water at which the machine might at any time be.   This was achieved by means of a glass tube, twelve inches in length, and about four in diameter, which was also attached to the side of the machine: this tube enclosed a piece of cork, that rose with the descent of the machine, and fell with its ascent, and one inch rise of the cork denoted a depth of about one fathom.  The principle upon which such a result was produced, and also the mechanical contrivance of this tube, entirely escaped the observation of Mr. Lee, amidst the hurry and constant anxiety attendant upon such a perilous navigation.

But not the least ingenious part of this curious machine, was that by which the horizontal motion was communicated to it.   This object was effected by means of two oars or paddles, formed precisely like the arms of a wind-mill, which revolved perpendicularly upon an axletree that projected in front; this axletree passed into the machine at a water joint, and was furnished with a crank, by which it was turned: the navigator being seated inside, with one hand laboured at the crank, and with the other steered by the tiller.

The effect of paddles so constructed, and turned in the manner stated, by propelling or rather drawing a body after them under water, will readily occur to any one without explanation.

These paddles were but twelve inches long, and about four wide.   Two smaller paddles of the same description, also projected near the head, provided with a crank inside, by which the ascent of the machine could be assisted.

By vigorous turning of the crank, says my informer, the machine could be propelled at the rate of about three miles an hour in still water.   When beyond the reach of danger, or observation of an enemy, the machine was suffered to float with its head just rising from the water's surface, and while in this situation, air was constantly admitted through three small orifices in the head, which were closed when a descent was commenced.

The efficient part of this engine of devastation, its magazine, remains to be spoken of.   This was separate and distinct from the machine.  It was shaped like an egg, and like the machine itself, was composed of solid pieces of oak scooped out, and in the same manner fitted together, and secured by iron bands, &c.  One hundred and thirty pounds of gun powder, a clock, and a gun lock, provided with a good flint that would not miss fire, were the apparatus which it enclosed.  This magazine was attached to the back of the machine, a little above the rudder, by means of a screw, one end of which passed quite into the magazine, and there operated as a stop upon the movements of the clock, whilst its other end entered the machine.  This screw could be withdrawn from the magazine, by which the latter was immediately detached, and the clock commenced going.  The clock was set for running twenty or thirty minutes, at the end of which time, the lock struck, and fired the powder, and in the mean time the adventurer effected his escape.

But the most difficult point of all to be gained, was to fasten this magazine to the bottom of a ship.   Here a difficulty arose, which, and which alone, as will appear in the ensuing narrative, defeated the successful operations of this warlike apparatus.

Mr. Bushnell's contrivance was this — A very sharp iron screw was made to pass out from the top of the machine, communicating inside by a water joint; it was provided with a crank at its lower end, by which the engineer was to force it into the ship's bottom: this screw was next to be disengaged from the machine, and left adhering to the ship's bottom.   A line leading from this screw to the magazine, kept the latter in its destined position for blowing up the vessel.

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I shall now proceed to the account of the first attempt that was made to destroy a ship of war, all the facts of which, as already stated, I received from the bold adventurer himself.

It was in the month of August, 1776, when Admiral Howe lay with a formidable British fleet in New-York bay, a little above the Narrows, and a numerous British force upon Staten Island, commanded by General Howe, threatened annihilation to the troops under Washington, that Mr. Bushnell requested General Parsons of the American army, to furnish him with two or three men to learn the navigation of his new machine, with a view of destroying some of the enemy's shipping.

Gen. Parsons immediately sent for Lee, then a sergeant, and two others, who had offered their services to go on board of a fire ship; and on Bushnell's request being made known to them, they enlisted themselves under him for this novel piece of service.   The party went up into Long Island Sound with the machine, and made various experiments with it in the different harbors along shore, and after having become pretty thoroughly acquainted with the mode of navigating it, they returned through the Sound; but during their absence, the enemy had got possession of Long-Island and Governor's-Island.  They therefore had the machine conveyed by land across from New-Rochelle to the Hudson river, and afterwards arrived with it at New-York.

The British fleet now lay to the north of Staten-Island, with a large number of transports, and were the objects against which this new mode of warfare was destined to act; the first serene night was fixed upon for the execution of this perilous enterprise, and sergeant Lee was to be the engineer.   After the lapse of a few days, a favorable night arrived, and at 11 o'clock, a party embarked in two or three whale boats, with Bushnell's machine in tow.  They rowed down as near the fleet as they dared, when sergeant Lee entered the machine, was cast off, and the boats returned.

Lee now found the ebb tide rather too strong, and before he was aware, had drifted him down past the men of war; he however immediately got the machine about, and by hard labour at the crank for the space of five glasses by the ship's bells, or two and a half hours, he arrived under the stern of one of the ships at about slack water.   Day had now dawned, and by the light of the moon he could see the people on board, and heard their conversation.  This was the moment for diving: he accordingly closed up overhead, let in water, and descended under the ship's bottom.

He now applied the screw, and did all in his power to make it enter, but owing probably in part to the ship's copper, and the want of an adequate pressure, to enable the screw to get a hold upon the bottom, his attempts all failed at each essay the machine rebounded from the ship's bottom, not having sufficient power to resist the impulse thus given to it.*

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* It yet remains a problem, whether the difficulty here spoken of will ever be fully obviated Mr. Fulton's torpedoes were never fairly brought to the test of experiment, though he and his friends entertained perfect confidence that they would not be found defective; in any of their operations.

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He next paddled along to a different part of her bottom, but in this manoeuvre he made a deviation, and instantly arose to the water's surface on the east side of the ship, exposed to the increasing light of the morning, and in imminent hazard of being discovered.   He immediately made another descent, with a view of making one more trial, but the fast approach of day, which would expose him to the enemy's boats, and render his escape difficult, if not impossible, deterred him; and he concluded that the best generalship would be to commence an immediate retreat.

He now had before him a distance of more than four miles to traverse, but the tide was favourable.   At Governor's-Island great danger awaited him, for his compass having got out of order, he was under the necessity of looking out from the top of the machine very frequently to ascertain his course, and at best made a very irregular zigzag track.

The soldiers at Governor's-Island espied the machine, and curiosity drew several hundreds upon the parapet to watch its motions.   At last a party came down to the beach, shoved off a barge, and rowed towards it.  At that moment sergeant Lee thought he saw his certain destruction, and as a last act of defence, let go the magazine, expecting that they would seize that likewise, and thus all would be blown to atoms together.

Providence however otherwise directed it{{:}} the enemy, after approaching within fifty or sixty yards of the machine, and seeing the magazine detached, began to suspect a yankee trick, took alarm and returned to the island.

Approaching the city, he soon made a signal, the boats came to him and brought him safe and sound to the shore.   The magazine in the mean time had drifted past Governor's-Island into the East river, where it exploded with tremendous violence, throwing large columns of water and pieces of wood that composed it high into the air.  Gen. Putnam, with many other officers, stood on the shore spectators of this explosion.

In a few days the American army evacuated New-York, and the machine was taken up the North river.   Another attempt was afterwards made by Lee upon a frigate that lay opposite Bloomingdale: his object now was to fasten the magazine to the stern of the ship, close at the water's edge.  But while attempting this, the watch discovered him, raised an alarm, and compelled him to abandon his enterprise.  He then endeavoured to get under the frigate's bottom, but in this he failed, having descended too deep.  This terminated his experiments.