During the era of the American Revolution, cannons did not fire exploding projectiles, so the image of explosions on the battlefield doesn’t apply. Mortars and howitzers did loft exploding shells in high arcs, but these were used almost exclusively against fixed positions like forts and towns. Sieges and a few other actions included a fair number of explosions, but in most combat, the loudest ka-boom was from the firing of cannons, seconded by the crack of dozens of muskets at once.
It wouldn’t have been a modern war, though, without a few big explosions. During the war’s eight years, there were a few REALLY BIG explosions, the kind that shook the earth, created mushroom clouds, and were heard for miles around. Here are five, well, more than five, actually, because we’ve lumped some similar incidents together.
1. HMS Augusta, Delaware River, October 23, 1777
A British army captured the city of Philadelphia in 1777, but supplying the city required unobstructed access to the Atlantic Ocean by way of the Delaware River. Two American forts, Mercer and Mifflin, commanded the river below the city, and the British army and navy began a concerted effort to reduce them. British warships worked their way close to Fort Mercer on the New Jersey shore, but the sixty-four-gun HMS Augusta and the smaller HMS Merlin ran aground. Under heavy bombardment, a fire broke out near Augusta’s stern that soon spread throughout the ship.
After an hour or so, the flames reached the ship’s gunpowder stores. The resulting explosion was heard up to thirty miles away and broke windows in Philadelphia.
The Augusta man-of-war of 64 guns with a sloop-of-war of 16 guns that had been playing on the fort took fire by some accident, & by the time the boats had got the men all well out, both blew up with such a prodigious noise that many people in this city thought it was an earthquake, tho’ the explosion was 9 miles distant.
2. American powder mills, New Jersey and Rhode Island, 1777 and 1779
Among the many challenges that faced the American war effort was procuring the vital materials required by an army, particularly before French assistance began to arrive. One of those vital materials was gunpowder, a commodity previously purchased from Great Britain. Stores of powder were procured from a number of sources, but consistently meeting long-term needs demanded domestic production.
The principles and methods of gunpowder manufacturing were well-known, but creating mills to consistently produce large quantities of good quality powder was no easy task. A number of powder mills were established, and the fate of two of them illustrates the dangers of working with volatile materials.
New Jersey had a powder mill in the town of Upper Evesham, present-day Medford, run by Adonijah Peacock. Quaker minister John Hunt in nearby Moorestown wrote in his diary on January 20, 1777:
This day Nijah Peacock was buried, a very ingenous man in Evesham. He had, since the wars began, erected a powder mill and carryed it on to considerable perfection till one day he was at work amongst his powder and by some means it catchd fire and kild him and hurt several of his family besides. It was said that the rhoof of the house was blown off and very much shattered to pieces with the blast of the powder heard for ten miles around.
In Rhode Island, a powder mill was built in 1776 in Centerdale, part of present-day North Providence, on the bank of the Woonasquatucket River. The mill received a load of damaged gunpowder to be refurbished in August, 1779. The newspaper reported:
Last Saturday Afternoon the Powder Mill in North-Providence, with a Store adjacent, containing almost two Tons of Powder, were blown up. By this affecting Accident, two worthy Men lost their Lives, viz Mr. Jacob Goffe, and Mr. Laban Beverly, both of this Town, who expired the same Evening. It appears that they were employed in re-manufacturing a parcel of damaged Powder, which took Fire in one of the mortars, supposed to have been occasioned by a flint that was perhaps among it when it was returned to the mill; the flame was instantly communicated to a Quantity of Saltpetre and Sulphur, and then to the finished Powder, which unhappily had not been removed to the Building provided to receive it. The explosion was heard several Miles round, and a beam of the Mill was thrown about three Quarters of a Mile from the spot where it stood.
3. British frigates, Narragansett Bay, August 1778
After entering an open alliance with the United States in early 1778, the first direct support given by France was a fleet of warships sent to cooperate with the Continental Army on the Atlantic coast. After menacing the mouth of New York harbor, the French ships moved on Rhode Island. A British garrison occupied the largest island in Narragansett Bay, supported by a squadron of frigates.
On July 30, French ships pushed up the Seconnet River on the east side of the island, forcing a British sloop and two galleys to be grounded and set on fire to prevent their capture; all three blew up when fire reached their powder magazines. Over the next several days, French men-of-war sailed into the passages of Narragansett Bay, trapping the frigates HMS Cerberus, Orpheus, Juno, and Lark, and another galley. On August 5, those ships too, heavily outgunned and with nowhere to escape, were grounded and set aflame. One at a time they exploded with tremendous force, sending flaming debris onto the shoreline.
The Explosion of some of our Frigates was very great, particularly that of the Lark, which had 76 barrels of powder in her Magazine . . . Some books and papers belonging to the Orpheus, were found three miles from the place where she blew up.
4. Storehouse of Captured Arms, Charlestown, South Carolina, 1780
After British forces captured the city of Charlestown (today’s Charleston), South Carolina, they had a lot to clean up. All over the city were caches of weapons and ammunition that their foes had been using to defend the besieged city. These materials were gathered and lodged in a storehouse, where officers and men of the Royal Artillery, responsible for managing the army’s surplus arms and ammunition, began to take an inventory. An accident occurred, apparently by the discharge of a loaded weapon, and the storehouse exploded with tremendous force, followed by a raging fire that caused hundreds of other loaded guns to fire, and destroyed a number of buildings in the town.
Without describing the sad sight of shattered, maimed, and half-dead people, who were struck down at the same time, or by the discharge of 5,000 mostly loaded weapons, many who were at a great distance were killed and wounded, and all the swords of the captured officers were melted.
5. Fort Crescent, Pensacola, May 8, 1781
The Gulf Coast saw an extensive campaign by Spanish forces to wrest port towns from British control. Among the strategic spots was Pensacola, where British, German, Loyalist, and Native American soldiers and warriors endured a two-month siege in March, April, and May 1781. Spanish forces under Bernardo de Gálvez invested the area and surrounded the town with a vastly superior force of regular army and militia troops, supported by a fleet of over twenty ships.
The garrison fought hard, tormenting the Spanish troops with several sorties by American Indian warriors, but in spite of being well-fortified the odds were against them. The denouement of the siege came on May 8, when a shell lobbed by a Spanish mortar dropped into the powder magazine of Fort Crescent, a key position in the British defenses. The resulting explosion laid waste to the fortification, leaving a dangerous and untenable gap in the defensive line. The garrison surrendered soon after.
About 9 o’clock, a. m., a shell from the enemy’s front battery was thrown in at the door of the magazine, at the advanced redoubt, as the men were receiving powder, which blew it up and killed forty seamen belonging to H. M.’s ships the Mentor and Port Royal; and forty-five men of the Pennsylvania Loyalists were killed by the same explosion; there were a number of men wounded, besides.
Diary of Lt. Christian Friedrich Bartholomai, in Bruce E. Burgoyne, trans., Enemy Views: The American Revolutionary War as Recorded by the Hessian Participants (Bowie, MD: Heritage Books, 1996), 396.