This is a kayak cache along the Hudson River to be found at or near high tide times. You're looking for a camoed cigar tube hanging over the water.
The backwater here is a shallow side channel separated from the main river channel by Rattlesnake Island.
This can only be accessed from the water. A kayak or small boat can get close enough to make the find.
You need to arrive at the cache near high tide, or within 2-hours either side of high tide at most. This should give you a 4-hour window of opportunity, twice each day. Log only, brng a pen.
Below is a link for Hudson Tide Prediction times. (Note: add about 30 minutes for the predicted high tide for Coxsackie.)
Hudson, NY Tide Predictor