Date: August 14th, 1776
Location: Harlem Heights, New York
Time: 5:00 AM
Early the next morning before it starts to lighten in the eastern sky, bugles sound throughout the British camps; rousing men from their slumber and having them stand to arms. Today is the day htat General Howe has chosen for the assault on the colonial works on Harlem Heights; all throughout the ranks, there is a keen sense of anticipation at the prospect of imminent action. After a very early morning meal, the redcoats assemble themselves by companies into their respective regiments and then begin to march forward into line.
By this time, the sky is beginning to lighten in the east. Just then, a number of British officers take a note of a strange object that seems to be floating in mid-air high over the colonial lines. This matter is quickly brought to the attention of General Howe and his staff; together as one, Howe and his staff raise their spyglasses on it. General Henry Clinton remarks out loud “what in God’s name is that thing? Some damnable colonial trick, I’ll wager...”
General Howe again focuses his spyglass on the object. A frown crosses his face as he says “trick or not, look at the basket attached to the bottom of that thing. There are two men in it, and they are high enough so they can see our deployments as they happen. If there be some way of sending messages to the ground, all chance at achieving surprise is lost. We must assume that this is the case, so here is what we will do. General Clinton?”
“You will order the troops to demonstrate as if we intend to carry out a frontal assault. I want the colonial lines probed to test their strength and see what happens. While this is going on, send to my brother Admiral Howe. Give him my compliments and say that he is to hold his fleet in readiness to board troops at a moment’s notice. Tonight under cover of darkness, we’ll leave a sufficient number of troops in place to make the colonials think we are still here. All other troops will quietly move to board Admiral Howe’s ships.”
“What is your plan, sir?”
“While we hold the colonials in place thinking that we are going to attack in force, the remainder of our troops will be aboard the ships of the fleet; the ships will be divided into two bodies. One will advance up the East River and land troops on the west bank of the river behind the Colonial lines. At this same time, the other half of the fleet will sail up Hudson’s River and do likewise by landing troops on the east bank. My plan is to stage a simultaneous assault and take the Colonial Army by surprise from the rear.”
“A capital plan, sir. What are your orders?”
“Send word to the battery commanders that they are to range their heaviest pieces on the colonial lines. When all is in readiness, they are to open fire. While this is going on, send out patrols to conduct reconnaissance and find out where the colonials are the weakest.”
“Very good, sir.”
High over the crest of Harlem Heights, the two-man crew in the observation balloon have sent their first report via telegraph to the ground station. The substance of the report is that the British are moving troops and guns into position, and that an attack is likely before very long. This information is immediately dispatched to General Washington’s headquarters, where it is received with much interest. After reading the report, Washington says “General Garrity, that balloon of yours has already proved its worth; it seems as if the British are preparing to mount an attack against us. I would not have known this until they actually opened fire. My compliments on your foresight, sir.”
“You are very welcome, sir. I am glad to have been of service. Do you have any orders for me?
“You are to return to your command and hold your troops in readiness to repel an expected British attack. Your own artillery will follow Colonel Knox’ lead when he decides to open fire.”
General Garrity snaps to attention, renders a salute and replies “yes, sir. I’m rather looking forward to giving the redcoats a taste of New England-style hospitality.” This last is delivered with a predatory grin as General Garrity mounts up and rides out. Across on the other side of the field, the British troops are standing to, with their regimental flags flying proudly in the early-morning breeze. At a signal, the British grand battery opens fire with 24-pdr guns, 32-pdr howitzers and heavy mortars; these pieces being the only ones with the range to hit the colonial positions. The volleys from the guns and howitzers are ill-timed and somewhat ragged, while the fire from the mortars has to be constantly adjusted (either by changing the elevation of the mortar tubes or varying the size of the powder charges).
The British artillery fire is inaccurate, with only a few balls and shells falling near their intended targets; most of the projectiles fall either short or long. Those that are long tend to overshoot by a considerable margin. By General Garrity’s standards, the fire is sloppy and poorly-delivered; by contemporary British standards, the performance of the artillery is acceptable. In response, Colonel Knox gives the signal for his artillery to return fire, and so they do. Rather than having small hand-held telescopes, Knox’ gunners have binoculars, clinometers and optical rangefinders previously provided by General Garrity. These devices alone make Knox’ fire far more accurate than it would otherwise have been. As accurate as it is, however, it is nothing to compare with the fire from General Garrity’s artillery. His 12-pdr smoothbores are machined to exacting tolerances; thus giving them windage that is much tighter than contemporary guns; tighter windage means less gas escaping from behind the projectile and therefore, more power, range and accuracy; the range is 1,800 yards at 5 degrees of elevation. Next are the guns in Garrity’s flying artillery, the two 1.65” Hotchkiss-pattern rifled mountain guns. These two pieces have a range of 4,000 yards
The best performance of all is from General Garrity’s 20-pdr rifled muzzleloaders; on open ground, these guns have a range of 2,000 yards at 5 degrees of elevation and up to 4,400 yards at 15 degrees of elevation.
General Garrity’s guns are also far more powerful than anything Colonel Knox has in his inventory; both batteries have their fire propelled by charges of black powder. The difference is that Garrity’s shells are loaded with high explosives. The shells from the 20-pdr RMLs are loaded with 3 lbs of TNT; the common shell and case shot fired by the 12-pdr smoothbores are loaded with 8 ounces and 2 ounces of TNT respectively. The mountain guns are an exception, with each of their shells having a filling of four ounces of Octol. For ignition, all guns (including the 1.65" mountain rifles) use friction primers
In terms of rate-of-fire, General Garrity’s 20-pdr RMLs and 12-pdr smoothbores can let off one shot every 90 seconds. Once again, the exceptions are the two mountain guns; their small size, light weight and breechloading mechanism mean that each of these pieces can discharge up to 12-15 rounds per minute. However, the usual rate-of-fire is 10 rounds per minute for rapid fire and 6 rounds per minute for sustained fire.
While the duel between British and American artillery is going on, both sides put forth skirmishers beyond their picket lines and have them make probing attacks in order to sound out any possible weaknesses in the opposing line. In these actions, the British come out very badly due in large part to the fire superiority that General Garrity’s skirmishers have. All of his men are armed with flintlock rifle-muskets, while the British are armed with the Brown Bess smoothbore. A British officer once said that a soldier with a smoothbore musket is able to hit a man at 50 yards and is lucky to be able to hit at 100 yards; and that anyone hit at 150 yards is exceedingly unlucky. Given that Garrity’s rifle-muskets have an effective range of 300-500 yards, his troops are able to engage and decisively defeat the British skirmishers without taking so much as a single casualty.
The artillery engagement continues for hours on end, with those British guns facing Colonel Knox’ battery taking no more than the expected number of casualties. This is most definitely not the case with the grand battery facing General Garrity’s position on the colonial right flank; numerous pieces are dismounted (or otherwise put out of service) and the casualties among the crews serving them are severe. Even so, General Clinton holds to General Howe’s plan and presses the engagement only so far as is necessary to make the Colonials think that a frontal attack is in the offing.
At General Howe’s headquarters, casualty reports from the grand battery on the left flank are coming in. There are looks of shock and disbelief at the damage that portion of the colonial artillery has been able to inflict. General Clinton looks to General Howe and says “my God, sir!!; I never would have thought that the colonials would be able to deliver so destructive a volume of fire upon us, and with such accuracy, too. There must be at least a full battalion of artillery on their right, if not more...”
General Howe replies “I have a good idea that damned thing in the air (whatever it might be) bears some responsibility for what is happening. Think of it, sir; such an enormously-high vantage point would give them a commanding view of the entire battlefield and enable the colonials’ artillery fire to be much more accurately directed. Send to my battery commanders and order them to keep up a good, hot masking fire until the sun starts to set. Afterwards, you and I will move the troops under cover of darkness to the landing and get them aboard Admiral Howe’s ships as speedily as possible. The sooner we are able to come down behind the colonial lines, the better I will like it. I will take charge of those troops going up the East River and you will command that contingent going up Hudson’s River.”
General Clinton nods his head by way of reply, then says “God’s arm strike with us, sir.”
Time: 6:30 PM
The British artillery fire continues until sundown, and for some little time thereafter. After the skies darken, the plan to move the bulk of British forces aboard ship and divide them for simultaneous landings on the colonial flanks is put into place. Unbeknownst to the British commanders, General Garrity’s observers in the balloon are equipped with night vision devices. They instantly see what the British are up to and send word back to General Garrity’s command post.
A feral grin crosses General Garrity face as he thinks to himself ‘a clever plan; it’s probably what I would do if I were in their position.’ A messenger is sent to General Washington’s headquarters with a document that reads as follows:
‘Sir, I have the honor to report that my observers have seen that much of the British force is moving to board ships in the East River. I believe that they may try to move and flank us. I respectfully request that you send out cavalry patrols to gain an appreciation of where the British might try to land on the left flank; will do likewise with the Black Horse Cavalry on the right.’
After the document was sent off, General Garrity calls for his executive officer and says “Jim, send word to the shipyard. Tell them to execute Operation: Nemo after sunset tomorrow.”
“Copy that, sir.”
Date: August 15th, 1776
Location: the waters of the East River, adjacent to Manhattan Island
In the aftermath of the meeting with David Bushnell on July 12th, General Garrity ordered that the construction of Bushnell’s vessel take place with all possible speed. Operations began in a dis-used corner of the Fraser Brothers shipyard on the west bank of the East River near Harlem Heights; David Bushnell and his staff are being assisted by General Garrity’s mechanics, carpenters and blacksmiths in the construction of a craft that has the potential to change naval warfare forever; the first practical submarine.
The vessel is in the form of an elongated barrel, with a center section measuring six feet in diameter and thirty feet long; the nose is rounded and the tail tapered in order to streamline it and to make the vessel more seaworthy. The hull is fabricated from stout oaken staves softened by steaming, fastened together in a jig, left to cool then fastened together in the manner of an ordinary barrel by wrought-iron hoops; the hull is waterproofed on the inside by brewer’s pitch (ordinarily used to line the inside of beer barrels) and on the outside by regular pitch.
Inside the hull, there is a forged-iron crankshaft which extends out of the rear end and is attached to a propeller; this arrangement is turned by four men who sit on a bench provided for that purpose. The helmsman sits at the rear of the vessel and takes his orders on making course changes from the commanding officer; this individual sits at the front of the vessel underneath a small, tower-like structure into which his head and shoulders extend. The structure is leak-proof, and is fitted with small, round windows on all sides so the commander can see where the vessel is going and if there are any other craft nearby. In this, he is aided by his seat, which is mounted don a swivel so it can turn in whatever direction is needed.
Aside from giving instructions to the rowing crew and the helmsman, the commander’s job involves operating the vessel’s diving apparatus (the bow-mounted diving planes) and the ballast system. Additionally, the commander is responsible for attaching the vessel’s explosive charge to the hull of the target. Given that British ships have copper sheets nailed to the bottoms of their hulls, the charge is attached by ramming it against the target; this triggers a second, smaller charge of explosive. This second explosive drives an iron spike into the timbers of the target ship’s hull; the spike serves to attach the explosive charge by a short length of line.
The explosive charge consists of 200 lbs of TNT in a waterproofed (made so by the application of brewer’s pitch) wooden barrel, weighted to be neutrally buoyant and to float just below the surface. When the barrel is attached to the target, the vessel’s commander pulls a lanyard that activates a clockwork detonation mechanism which will set off the explosive charge after a pre-set delay; this allows the vessel to withdraw to a safe distance before the charge explodes.
In another part of the shipyard, the first explosive charge is being made by two of General Garrity’s ordnance men. The TNT is carefully melted, then poured into the barrel and allowed to cool. Once the explosives have solidified, the clockwork detonating system is attached to the outside of the barrel and the safety is engaged.
Among the people attached to David Bushnell’s staff is Sgt. Ezra Lee from the Continental Army. By mutual agreement between Bushnell and General Garrity’s engineers, Sgt. Lee was chosen to command the submarine (now named the ‘Turtle’); five other men were chosen to make up the rest of the Turtle’s crew. Over the next two weeks, the six men underwent an intensive training program during which all phases of the Turtle’s operation were practiced at length.
When word was received from General Garrity on August 14th to execute Operation: Nemo, Bushnell wasted no time in getting the submarine into the water and armed. In order to save the energy of the Turtle’s crew, the vessel was towed out into the East River at 6:30 PM and brough to a position where the river’s current would take the submarine downstream toward the British fleet. When the Turtle was ¾ mile from the ships, Sgt. Lee submerged his vessel so that he and his crew could make their attack run.
Slowly, stealthily, the Turtle crept up on the anchorage of the British fleet. Operating under the assumption that the largest vessel present would be the fleet flagship, Sgt. Lee surfaces the Turtle until the viewports in the conning tower are just barely above water. Before very long, the target is sighted.
The vessel in question is HMS Eagle, a 64-gun 3rd-Rate ship-of-the-line and flagship of Admiral Richard Howe. Presently, the ship is at anchor while the Admiral and his officers are directing the loading of General Howe’s troops aboard the other ships of the fleet. By 11:00 PM, the Turtle is just 100 yards away; aboard her, Sgt. Lee positions his vessel for attack.
Aboard ship, General Howe is conferring with his brother the Admiral about the plan to use the fleet to land troops behind the colonial lines. Below HMS Eagle’s waterline on the ship’s starboard side, the Turtle comes into contact with the target’s hull. The point of contact is the tip of an eight-foot wooden spar, and the end of which is a small, powder-filled cartridge attached to the end of an iron spike. There is a ring attached to the shaft of the spike; a mooring line runs from the spike to the wooden barrel containing 200 lbs of TNT and the exploder mechanism. When the spar hits HMS Eagle’s hull, the impact sets off the powder cartridge, drives the iron spike through the exterior copper sheeting and into the timbers. Once the spike is in place, Sgt. Lee pulls the lanyard to activate the explosive charge’s clockwork detonator mechanism; before the Turtle put off from shore, the delay was set at 90 minutes. Carefully, Sgt. Lee backs the Turtle away from the British ship and heads back towards shore.
The noise created when the spar hits HMS Eagle’s and the powder cartridge goes off is a loud ‘THUMP’. Immediately, the deck watch raises the alarm and runs to both sides of the ship to see if anything is amiss. Shortly thereafter, a midshipman comes to HMS Eagle’s great cabin and reports to Admiral Howe. He says “begging your pardon, sir. That noise we heard a short time ago seems to have come from a piece of driftwood which floated into the ship’s hull on the aft quarter of the starboard side; no damage was done.”
“Very good, Midshipman Price. You may return to your duties.”
Admiral Howe and his brother return to their conference; General Howe says “Richard, you will command that part of the fleet which will sail up the East River. I will command the ships which will sail up Hudson’s River from HMS Erebus; we should plan to sail at dawn”
“Very good, William. Together, we’ll land troops behind both flanks of the colonial army and cut them off from any avenue of retreat.”
“Indeed. Between the two of us, we’ll show those damnable colonials the meaning of the king’s name.” The meeting comes to an end, and General Howe is piped off HMS Eagle. He returns to HMS Erebus and begins to issue the necessary orders for his part of the operation. Back aboard HMS Eagle, many of the crew are settling down for the last night they will ever see.
Time: 9:15 PM
The clockwork detonator attached to the explosive-filled barrel performs its design function and causes a spring-loaded plunger tipped with a firing pin to fly forward and strike a percussion cap. In turn, the percussion cap goes off and causes the charge’s blasting cap to detonate the main charge of 200 lbs of TNT. The barrel containing the explosives was anchored to the hull of HMS Eagle, and floating five feet below the ship’s waterline; the magnitude of the blast was such that it ripped a thirty foot hole in the ship’s hull. Due to the incompressibility of water, the rebounding pressure wave from the explosion caused even more damage to the ship’s timbers. Not suprisingly, HMS Eagle begins to sink almost immediately.
One moment, Admiral Howe and his officers were talking in the great cabin. The next, they were all violently thrown from their seats arund the captain’s table. The admiral himself escaped with bumps, bruises and a concussion; however, some of the other officers weren’t quite so lucky. The ship’s sailing master suffered a broken collarbone and a dislocated right shoulder, while HMS Eagle’s captain suffers from a number of broken ribs from the impact of being thrown against the wall of the cabin. The other officers present suffer numbers of other injuries.
Below deck, the situation for HMS Eagle’s crew is dire. Most of the men in the immediate vicinity of the blast were killed, either by the blast or by drowning from the sudden inrush of cold water. Only those officers and men on those portions of the upper gun deck, quarterdeck and foredeck farthest from the blast are in a position to escape. HMS Eagle takes a severe list to starboard and then begins to heel over as she sinks. Of her original complement of 300 men, nearly 200 are killed or wounded.
Not surprisingly, the other ships in this part of the fleet are in an absolute panic over what happened. A number of them open fire with their guns, thinking that some Colonial warship managed to get close undetected and open fire. Aboard others, jumpy sentries and members of the deck crew open fire with muskets and swivel guns at imaginary threats on the East River.