This is one of 262 drawings and 2 paintings presented to the Museum by the artist's family in 2012, and related to John Kingsley Cook's wartime service in the merchant navy between December 1940 and August 1945. It is drawn on the back of a navigational chart published by the US Coast and Geodetic Survey, showing soundings (deep), letters indicating the quality of the bottom, part of a compass rose and graticule. The fragment is part of the bottom edge of the chart.