TAPPAN SEA. 12-18 July 1776. The Tappan Sea, now called Tappan Zee, is the widest stretch of the Hudson River, to the north of Manhattan. On 12 July, 10 days after the British troop build-up started on Staten Island, the warships Phoenix (forty guns) and Rose (twenty guns), along with a schooner and two tenders, ran the American batteries that were supposed to be guarding the entrance to the Hudson and sailed forty miles upstream to anchor, virtually unscathed, in the Tappan Sea. On 3 August Lieutenant Colonel Benjamin Tupper led five small boats in a gallant but unsuccessful attack against the flotilla. On 16 August an attack by fire rafts also failed, although the Phoenix was seriously threatened and the British commander was so alarmed by this attempt that he withdrew. Rerunning the gauntlet, he rejoined the fleet on 18 July.
This naval demonstration demoralized the Americans, showing that British ships could move at will against the flanks and rear of the main army in and around New York City. Commander in Chief George Washington and his generals were further bewildered as to Howe's strategy—where would he move from Staten Island? As for the immediate purpose of the naval demonstration, other than testing American defenses, and preparing for a link-up with General John Burgoyne's expected advance from Canada, Washington supposed that it was to cut the flow of American supplies by water and land along the Hudson, or to supply arms to Loyalists in the region.
One serious aspect of the affair was the ludicrously poor performance of many American troops. Not more than half the artillerists went to their guns, and these scored only a few insignificant hits, although they fired almost 200 shots at close range. Several men were killed or wounded because they carelessly failed to sponge their guns, while hundreds of troops neglected their duties to play spectator.
revised by Barnet Schecter