In May, 1775, efforts were undertaken by the Massachusetts Committee of Safety to prevent provisions from reaching the British Army trapped in Boston. Today we'll examine accounts detailing the activities of Massachusetts privateers to achieve that goal.
It appears that by early fall of 1775, privateers from Newburyport, Beverly, Salem and Plymouth were actively cruising the waters off of Massachusetts Bay in search of supply ships destined for Boston. Many of these privateers traveled in "wolf packs" that varied in size from a few ships to over twenty. One such wolf pack from Newburyport consisted of twenty-five vessels and over 2800 men. A second Newburyport armada boasted thirty vessels.
According to reports from the Essex Gazette, Massachusetts privateers were far more successful in cutting off British supplies than their land based counterparts. As early as September 9, 1775, the newspaper reported that "Last Saturday a privateer belonging to Newburyport carried into Portsmouth a schooner of forty-five tons, loaded with potatoes and turnips intended for the enemy in Boston."
Two months later, the Lee, a privateer under the command of one Captain Manly, captured the British vessel Nancy. According to a December 7, 1775 description, "Captain Manly, in the Lee, a vessel of war, in the service of the United Colonies, carried into Cape Ann a large brig called the Nancy which he took off that place, bound from London to Boston, laden with about three hundred and fifty caldrons of coal; and a quantity of bale goods, taken by Captain Manly, was carried into Salem. She is about two hundred tons burthen, and is almost a new ship."
Of course, the Nancy was a military ordinance supply ship from Woolwich, England and also contained several brass cannons and a large quantity of arms and ammunition. Interestingly, that same account hints that Massachusetts privateers were becoming problematic for the British. "Several vessels loaded with fuel, provisions of various kinds, &c, bound to Boston, have been carried into Salem and Beverly within a few days past."
A few weeks after the capture of the Nancy, the Essex Gazette announced Captain Manly had struck again. "Captain Manly has, within a few days past, taken another valuable prize, a sloop from Virginia bound for Boston, loaded with corn and oats; fitted out and sent by Lord Dunniore."
On Christmas Day, a Plymouth based privateer successfully intercepted a supply sloop from New York. "On the 25th of December last  was taken by a Plymouth privateer and carried in there a small sloop from New York, Moses Wyman, Master, laden with provisions fur the ministerial army in Boston, consisting of thirty-five fresh hogs, one hundred barrels of pork, fifty barrels fine New York pippins, twenty firkins hog's feet, some quarters of beef, turkeys, &c., &c."
Less than six months after Massachusetts privateer operations commenced, eight captured vessels had already been brought into Newburyport. One period account from March 6, 1776 describes the fifth vessel captured. "A few days since, the Yankee Hero sent into Newburyport another prize, a fine brig of about two hundred tons burthen, laden with coal, cheese, &c, bound for White Haven, for the use of the ministerial butchers, under the command of General Howe, Governor of Boston. This is the fifth prize out of eight which sailed states from the above port, and we are in hopes of giving a good account of the three remaining."
Even as the British army was preparing to evacuate Boston, the famed Captain Manly was still harassing Crown shipping lanes. On March 14, 1776 "a transport brig of sixteen guns, laden with naval stores and provisions bound from Boston for the ministerial fleet at the southward was taken. A ship of two hundred and forty tons also captured by Captain Manly about this time was shipped with six double fortified four-pounders, two swivels, and three barrels of powder, while the cargo consisted of one hundred and seventy-five butts of porter, twelve packages of medicine with largo quantities of coal, sourkrout, &c, besides a great number of packages for the officers in Boston. She also brought out sixty live hogs, but only one of them was alive when she was carried in."
Privateering proved to be quite profitable for Massachusetts coastal towns. At the height of the war, almost one hundred privateer vessels hailed from Newburyport alone. According to historian George Clark, over a period of four months (November 1775 to March 1776) the number of British vessels captured en route to Boston "amounted to thirty-one, their tonnage to 3,045 tons."