The role played by the East India Company in European expansion in early modern Asia is of such importance that it has generated a large body of scholarly literature. However, the logbooks of the East Indiamen, compiled by their captains, are largely overlooked as a primary source for the history of navigation, despite the wealth of information such firsthand, “from below” documents could provide about those voyages. As part of the Global Sea Routes (GSR) project, this essay analyses the voyage of the Nassau (1781–85) along four main themes: the peculiarities of navigation during the Age of Sail, when the duration of a voyage was difficult to predict and subject to a range of possible accidents; the concrete reality of life on board, oscillating between the various activities of the crew and the episodes of desertion and insubordination that broke its daily routine; her military deployment, as the Nassau was directly involved in operations related to the Second Anglo-Mysore War; and, finally, her commercial activities, from the port cities of India to the seas of China.