On the border between the lower gun and orlop decks, two sandglasses were discovered. In spite of their exposed position next to a heavy cannon, they were remarkably intact. This was because they were embedded in remains of cloth and rope. The large sandglass was possibly used for keeping time in connection with watch guards and the smaller for logging the speed of the sailing ship.
Sandglasses were used to measure time. Often there were three aboard a vessel, two larger used for keeping times of watches usually in four hour shifts, and a smaller used for measuring vessel speed. This smaller timeglass was used in conjuction with a knotted rope. The distance that the rope went out over a specified time was determined as the ships speed, in knots.