The American Revolution witness several examples of Yankee ingenuity that astonished the foes of the United States and delighted their friends. David Bushnell while an undergraduate at Yale in 1775 developed the plans for the Turtle, the first submarine used in combat. Among his innovations was using water as a ballast to raise and lower the submarine, a screw propeller to move the Turtle and a time bomb to serve as the weapon of the Turtle.
The Turtle was constructed and in August General George Washington authorized an attack on HMS Eagle, the flagship of Admiral Richard Howe. The attack was made on September 7, 1776. The Turtle was piloted by Sergeant Ezra Lee. The attack did not succeed. On February 20, 1815 Ezra Lee wrote a letter describing the attack to General David Humphreys:
Judge Griswold, & Charles Griswold Esq. both informed me that you wished to have an account of a machine invented by David Bushnell of Say. Brook, at the commencement of our Revolutionary war. In the summer of 1776, he went to New York with it to try the Asia man of war: – his brother being acquainted with the working of the machine, was to try the first experiment with it, but having spent untill the middle of August, he gave out, in consequence of indisposition. – Mr. Bushnell then came to General Parsons (of Lyme) to get some one to go, and learn the ways & mystery of this new machine, and to make a trial of it.
General Parsons, sent for me, & two others, who had given in our names to go in a fire ship if wanted, to see if we would undertake the enterprize: – we agreed to it, but first returned with the machine down Sound, and on our way practised with it in several harbours. – we returned as far back as Say-Brook with Mr Bushnell, where some little alterations were made in it – in the course of which time, (it being 8 or 10 days) the British had got possession of Long Island & Governor’s Island – We went back as far as New Rochelle and had it carted over by land to the North River. –
Before I proceed further, I will endeavour to give you some idea of the construction of this machine, turtle or torpedo, as it has since been called. – (1) Its shape was most like a round clam, but longer, and set up on its square side – it was high enough to stand in or sit as you had occasion, with a (2) composition head hanging on hinges. – it had six glasses, inserted in the head, and made water tight, each the size of a half Dollar piece, to admit light – in a clear day, a person might see to read in three fathoms of water – The machine was steered by a rudder having a crooked tiller, which led in by your side, through a water joint. – (3) then sitting on the seat, the navigator rows with one hand, & steers with the other – it had two oars, of about 12 inches in leangth, & 4 or 5 in width, shaped like the arms of a windmill, which led also inside through water joints, in front of the person steering, and were worked by means of a wench (or crank) and with hard labour, the machine might be impelled at the rate of 3 nots an hour for a short time – Seven hundred pounds of lead were fixed on the bottom for ballast, and two hundred weight of it was so contrived, as to let it go in case the pumps choaked, so that you could rise at the surface of the water. – It was sunk by letting in water by a spring near the bottom, by placing your foot against which, the water would rush in and when sinking take off your foot & it would cease to come in & you would sink no further, but if you had sunk too far, pump out water untill you got the necessary depth – these pumps forced the water out at the bottom, one being on each side of you as you rowed – A pocket compass was fixed in the side, with a piece of light (4) wood on the north side, thus +, and another on the east side thus -, to steer by while under water – Three round doors were cut in the head, (each 3 inches diameter) to let in fresh air, untill you wished to sink, and then they were shut down & fastened – There was also a glass tube (5) 12 inches long and 1 inch diamater, with a cork in it, with a peice of light wood, fixed to it, and another peice at the bottom of the tube, to tell the depth of discent, – one inch rise of the cork in the tube gave about one fathom water, – It had a screw, that peirced through the top of the machine, with a water joint, which was so very sharp that it would enter wood, with very little force, and this was turned with a wench, or crank, and when entered fast in the bottom of the ship, the screw is then left, and the machine is disengaged, by unscrewing another one inside that held the other. From the screw now fixed on the bottom of the ship, a line – led to & fastened to the mazagine, to prevent its escape either side of the ship – the magazine was directly behind you on the outside, and that was faced from you by unscrewing a screw inside – Inside the magazine was a clock machinery, which immediately sets a going after it is disengaged & a gun lock is fixed to strike fire to the powder, at the set time after the Clock should rundown – The clock might be set to go longer or shorter – 20 or 30 minutes was the usual time, to let the navigator escape – This magazine was shaped like an egg, & made of oak dug out in two peices, bound together with bands of iron, corked & paid over with tar so as to be perfectly tight, and the clock was bound so as not to run untill this magazine was unscrewed …..
I will now endeavour to give you a short account of my voyage in this machine. – The first night after we got down to New York with it, that was favourable, (for the time for a trial, must be, when it is slack water, & calm, as it is unmanagable in a swell or a strong tide) the British Fleet lay a little above Staten Island We set off from the City – the Whale boats towed me as nigh the ships, as they dared to go, and then cast me off – I soon found that it was too early in the tide, as it carried me down by the ships – I however hove about, and rowed for 5 glasses, by the ships’ bells, before the tide slacked so that I, could get along side of the man of war, which lay above the transports – The Moon was about 2 hours high, and the daylight about one – when I rowed under the stern of the ship, could see the men on deck, & hear them talk – I then shut down all the doors, sunk down, and came under the bottom of the ship, up with the screw against the bottom but found that it would not enter – (6) I pulled along to try another place, but deviated a little one side, and immediately rode with great velocity, and come above the surface 2 or 3 feet between the ship and the daylight – then sunk again like a porpoise I hove partly 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 4 miles to go, before passing Governor’s Island. – So I jogg’d on as fast as I could, and my compass being then of 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 While on my passage up to the City, my course owing to the above circumstances, was very crooked & zig zag, and the enemy’s attention was drawn towards me, from Governors Island – When I was abreast of the fort on the island 3 or 400 men got upon the parapet to observe me, – at leangth a number came down to the shore, shoved off a 12 oar’d barge, with 5 or 6 sitters, and pulled for me – I eyed them, and when they had got within 50 or 60 yards of me, I let loose 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, but as kind Providence would have it, they took fright, and returned to the island, to my infinite joy. – I then weathered the Island, and our people seeing me, came off with a whaleboat, and towed me in – The Magazine after getting a little past the Island, went off with a tremendous explosion, throwing up large bodies of water to an immense height. (7)
Before we had another opportunity to try an experiment our army evacuated New york, and we retreated up the North River as far as fort Lee – A Frigate came up and anchored off Bloomingdale. I now made another attempt upon a new plan – 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 abondon this scheme, then shutting my doors, I dove under her, but my cork in the tube, (by which I ascertained my depth) got obstructed, and deceived me, and I descended too deep & did not track the ship, and I then left her – Soon after the Frigate came up the river, drove our Crane galley on shore, and sunk our Sloop, from which we escaped to the shore –
I am &c. E. Lee.
General Humphreys made notes on the letter:
For General David Humphreys –
(1) This machine was built of oak, in the strongest manner possible, corked and tarred, and though its sides were at least six inches thick, the writer of the forgoing, told me that the pressure of the water, against it, at the depth of two fathoms was so great, that it oozed quite through, as mercury will by means of the air pump. Mr. Bushnell’s machine was no larger than just to admit one person to navigate: – its extreme leangth was not more than 7. feet. – When lying in the water, in its ordinary state without ballasts, its upper works did not rise more than 6 or 7 inches out of water –
(2) This composition head, means of composition of Metals – something like bell metal, and was fixed on the top of the machine, and which afforded the only admission to the inside –
(3) The steering of this machine was done on the same principles, with ordinary vessels, but the rowing her through the water, was on a very different plan – These oars, were fixed on the end of a shaft like windmill arms, projected out, forward, and turned at right angles with the course of the machine, and upon the same principles that windmill arms are turned, by the wind these oars, when put in motion as the writer describes, draws the machine slowly after it – this moving power is small, and every attendant circumstance, must cooperate with it, to answer the purpose, calm waters & no current –
(4) This light wood is what we sometimes call fox fire, and is the dry wood that shines in the dark: – this was necessary as the points of the compass could not readily be seen without –
(5) The glass tube here mentioned, which was a sort of thermometer, to ascertain the depth of water the machine descended, is the only part that is without explanation – the writer of the forgoing, could not reccollect the principles on which such an effect, was produced, nor the mechanical contrivance of it – He only knows that it was so contrived that the cork & light wood rose or fell in the tubes, by the ascent or descent of the machine –
(6) The reason why the screw would not enter, was that the ship’s bottom being coppered it would have been difficult under any circumstances to have peirced through it – but on attempting to bore with the auger, the force necessary to be used in pressing against the ships bottom, caused the machine to rebound off this difficulty defeated the whole. – the screw could not enter the bottom, and of course the magazine could not be kept there in the mode desired –
(7) When the explosion took place, General Putnam was vastly pleased, and cried out in his piculiar way – “God’s curse ’em, that’ll do it for ’em.”