Once firmly in the capital Howe believed that he would have secure control of Maryland, Pennsylvania, and New Jersey.

He could achieve this and be back at New York in time to meet Burgoyne, perhaps at Albany.

Then he would hold the colony of New York from Staten Island to the Canadian frontier.

Howe found that he could send ships up the Hudson, and the American army had to stand on the banks almost helpless against the mobility of sea power.

Washington's left wing rested on the Hudson and he held both banks but neither at Peekskill nor, as yet, farther up at West Point, could his forts prevent the passage of ships.
It was a different matter for the British to advance on land.