Ocean tides determine river currents much more strongly than does the flow of fresh water in the river. During flood tides, the Atlantic flows up the Hudson. During ebb tides, the water flows back out to sea. If you're going to paddle to the Statue of Liberty, you can go out on an ebb tide and come back on a flood tide. The current works with you in both directions.
Tides occur at different times every day.
Within a given twenty-four hour period, flood tides occur twice. So do ebb tides. Slack tides occur three or four times. The chart below shows the times of flood tides, ebb tides, slack tides and current speeds for July 19, 1999. To learn more about the Hudson River, click here.