Fixed Points

2 March – 17 March 1776

“Glad to see the backs of that lot.”

The topmasts of the British fleet were disappearing over the horizon, late on the morning of 17 March, as a southwesterly wind ruffled the tall mans wig. Contrary winds had kept the Fleet in-harbor the last couple of days, and both sides were relieved when the wind swung around to a more favorable azimuth. Over 10,000 British soldiers, and some 1000 Loyalist civilians, could begin their voyage to Nova Scotia.

“What now, General?”

“Off to New York. General Lee has begun the fortifications. Howe will likely regroup in Halifax, then sail for New York. Boston is important, but not as strategically important as New York and the Hudson Valley. I’ll be off after I’ve met with my staff.”

“Very good, sir.”

17 March is Evacuation Day in South Boston, co-located on the calendar with St. Patrick’s Day. On that day in 1776, the British military and as many Loyalists as could, left Boston Harbor aboard His Majesty’s Navy. Forcing the British Beantown retreat was the first major American victory of the War, coming eleven months after the commencement of hostilities. The lever that forced the action was the American occupation of the Dorchester Heights south of Boston. The hills commanded the Harbor and City, and while both sides were aware of the strategic value, neither had occupied the ground. British General William Howe had planned to fortify the Heights during the previous Summer, but the leaking of those plans had caused the Rebels to occupy the Charleston peninsula North of town. There, they controlled the passage through which amphibious forces would have to pass. As the Americans controlled the land approaches, the only way for His Majesty’s Army to occupy the Dorchester ground, was by frontal assault from the sea. The Battle of Breed’s Hill in June was the British attempt to dislodge the Rebels from the peninsula. While successful in the objective, the cost of victory was so dear, the British could not mount another offensive expedition.

Arriving in June 1775 to take command of operations around Boston, George Washington looked for ways to break the stalemate the siege had become. Chief of Artillery COL Henry Knox proposed transporting cannon from Fort Ticonderoga in Upstate New York, to Boston. Dispatched to the Fort in November, Col Knox oversaw the transport of 60 tons of artillery and supplies 300 miles over 56 days. This “Noble Train of Artillery” has been hailed as one of the greatest logistical feats of the War. These days, you’d whistle up some helicopters and be done in a few hours. Then, it looked like this:

A typical 6-pound field cannon tube weighed around 1000 lbs (450 kg). Over hill, over dale, they did walk the snowy trail. And those caissons went rolling along at 5 1/2 miles (9 km) per day. Weapons started arriving in late January, and Washington positioned some West of town in Cambridge and Lechmere’s Point. The latter was the former estate of Loyalist Richard Lechmere, and as he had left for England early in the War, he had no use for it. Haven’t even gotten the Country started, and already, Americans are stealing land. The remainder of the supplies were reserved for the yet-to-be-built Dorchester Heights fortifications.

Building, and more to the point, defending, those fortifications would take men. A Council of War convened at Washington’s behest, agreed, and calls went out to surrounding Colonies for men-at-arms. By mid-February, Washington had 9000 regular-army Continentals, and 4500 militia at his disposal. Although Intelligence put Howe’s force around 6000 men, in reality, the garrison was closer to 9000 soldiers.

Additional Councils agreed that an assault across a narrow isthmus was inadvisable, but did agree to fortify Dorchester Heights, and bombard Boston. The British had control of the Charlestown peninsula by dint of victory at Breed’s Hill, but were otherwise surrounded by Rebels, and mostly confined to the City proper. As it would be costly for the Continentals to force their way in, so it would be for the British trying to get out. Informants had advised Gen Howe of the American plan to fortify the position, but the only action taken was a raid that burned some buildings. Washington’s problem was fortifying the Heights unnoticed, while under the direct observation of British forces. LTC Rufus Putnam had a plan.

Putnam had extensive military engineering experience working with the British in the French and Indian War, and spent his own time studying the subject. He was millwright prior to the Revolution, and those folks can fix anything. His plan was to prefabricate fortifications at remote locations, then assemble and secure them, literally overnight. Normal practice would have been to dig holes for the posts, but frozen ground, and the need for stealth, argued for another approach. The walls were knocked-down timber frames, that were to be erected, then filled with dirt and hay bales: effective defense against small-arms and grapeshot. The walls were to be augmented by felled trees laid longitudinally in front of the walls, as well as barrels full of rocks to be deployed against attackers. In order to mask movement, Putnam employed facines, or screens made of woven vines and twigs, to be placed between the path, and the observers. To that end, Washington had soldiers out in the woods for weeks hunting and gathering suitable flora. Military procurement at the time was much less complex.

With all supplies from Fort Tico in place by the end of February, Washington decided it was go-time. On the night of 3 March, he ordered the western batteries to fire on the town. British forces returned fire, but not much damage by either side. The exercise was repeated the next night. On what is described as a ‘balmy’ evening, and the third night of the bombardment, 2500 men moved toward the Dorchester Heights. Aided by a low fog, they erected the fascines to mask movement, along with stacked hay bales to absorb and redirect sound; similar to the noise-control walls along freeways. More hay was strewn along the path. In addition, the soldiers had wrapped the wagon wheels with cloth. It was as stealthy an operation as the 18th Century would allow. Halfway through the night, 3000 more men arrived to relieve the force. George Washington was present, providing encouragement and support, reminding the soldiers that 5 March was the sixth anniversary of The Boston Massacre: “Remember, it is the fifth of March, a day ever to be forgotten; avenge the death of your brethren, . . .”. This was the first recorded use of an event remembrance as motivator in American military history, and certainly apropos for the circumstances.

This particular 5 March, General William Howe awoke to the sight of an enemy fort, with a commanding view of the town and harbor, where none had been hours earlier. ‘Stunned and amazed’ wasn’t in it. Howe and staff didn’t waste any time; planning an assault with 2400 men that night against the position. Movement of the force began at 0800 on the 5th, and were expected to transit to Castle William, East of the Heights, then land at Dorchester Point.

The Long Wharf embarkation point is at upper left, and Castle William is the island with the red fortifications. The landing at Dorchester Point, directly West of Castle William, would have the British approaching the Heights from the rear, over nonlinear terrain. Gen Washington had prepared a sort of ‘dead-man’ switch, in that he had positioned two floating batteries, and transport for 3000 men, to invade Boston from Cambridge, if the British moved against Dorchester Heights. That move was hampered by the onset of inclement weather, causing two ships to run aground, and delaying force arrival at Castle William. This, in turn, caused the high tide to be missed, and pushed H-hour to midnight. In the interim, Howe ordered additional forces to the scene, and boarded transports throughout the day. I am sure many life choices were questioned when faced with the prospect of riding in an open boat through a gale. The inclement weather turned out to be a right nor’easter, lasting into the night, and forcing Howe to call off the attack. With some 6000 men on the Heights, and a convincing argument from his Chief Engineer that the American defenses were likely to be very hard to overcome, Howe accelerated his timetable for abandoning Boston, and on 8 March, sent a note to Washington that he would not burn the town, if his force was allowed to leave unmolested. Boarding took a week, and then another couple of days of uncooperative weather. On 17 March 1776, the British left Boston.