This piece of slate has been marked out as a reusable deck log to record the hourly progress of the ship for noting down later in the ship's formal log. Each side has a grid with seven columns marked out. These are headed: 'H', for hour (the time); 'K', for knots (the ship's speed, found by casting a log), 'HK', for fractions of knots, 'F', for fathoms; 'Cors' or 'Cours', for the ship's heading; 'Windes' or 'Winds', for the wind's speed and direction, and 'Remarkable Things', for any other notable occurrences or observations. Numbers referring to the hours are also written down in the 'H' column on each side. The slate is slightly damaged, so that not all the column headings remain on one of the sides.

The slate was one of a number of objects recovered from a wreck on the Goodwin Sands in the English Channel. This was possibly the 'Stirling Castle', which went aground during the Great Storm of 1703.