Set on a sultry afternoon in 1870, a square rigger tows outward with the aid of a paddle tug. In the foreground, spritsail barges are loading sand and gravel on one of the numerous sand bars at the mouth of the River Thames.
The banks comrpised many grades and types of sands and gravels, which were used in numerous industrial processes, including construction, castings and cleaning.
The barges would moor over a bank on a falling tide; they would then have two to three hours work, often taking two tides to fully load. These barges also loaded muds for the brickyards. They would sail into a marsh creek until aground and then excavate the surrounding banks into the hold of a vessel.