ATLANTIC CROSSING. Allowing for calms and storms, it normally took an eighteenth-century sailing vessel a month to cross from America to England and twice that time to return. (Westerly winds prevailed.) Four months would be a reasonable time for a British official to wait for a reply to a dispatch sent to America. Instances of faster communication can be cited, but on the other hand the last dispatches from Britain that General William Howe received in Boston before evacuating that place on 17 March 1776 were dated 22 October 1775. In the autumn of 1775, thirty-six unarmed supply ships were sent from Britain for Boston, but only thirteen arrived. The rest were either captured by American naval vessels and privateers or driven to the West Indies by the exceptionally bad weather that winter.
Arming the victuallers (provision ships) reduced losses from privateers to negligible amounts during the years 1776 to 1778. Gathering supply ships into convoys guarded by Royal Navy warships began in 1779 as a response to the threat posed by the French navy, and very few major ships were lost thereafter, either to American privateers or French squadrons. But convoying increased the time of passage, since the convoy traveled at the speed of the slowest ship ("convoy speed"). A convoy that left Britain on 19 July 1779, for example, arrived at New York on 22 September. A second convoy left Ireland on 24 December and arrived at Charleston, South Carolina, only in early March 1780.
While the British army in America was victualled largely from Britain and Ireland, commanders of captured American ports, especially New York City, did all they could to obtain supplies from the surrounding country-side, an illicit trade (from the rebel point of view) that was never extinguished.
Bowler, R. Arthur. Logistics and the Failure of the British Army in America, 1775–1783. Princeton, N.J.: Princeton University Press, 1975.
revised by Harold E. Selesky