While looking through New York: A Pictorial History by Marshall B. Davidson, Charles Scribner’s Sons: 1977, I came across a drawing of the funeral of General Fraser at Saratoga.  This includes the waterfront along the Hudson River showing quite a number of bateaux, plus three scows, one of which has a cannon on it.

A few days later, someone posted a link to a high-resolution image hosted by Brown University.  See here: http://dl.lib.brown.edu:8080/ImageServer/scrollnav.jsp?filename=1168005686203125.jp2.

Here is an excerpt from the image with the bateaux.