 The American commanders had left themselves vulnerable to a potentially decisive counter-attack.While they were preoccupied at the western end of Lake Ontario, Commodore Yeo had arrived in Kingston, accompanied by 465 officers and seamen of the Royal Navy, to take charge of the British squadron.Embarking troops under Prevost, who happened to be in Kingston on public and Army business, he almost immediately attacked the American base in the Second Battle of Sacket's Harbor on 29 May.