Seen as a crucial historical step in the development of 'modern' institutional healthcare, eighteenth-century British naval medicine has traditionally been studied from the point of view of the state and of physicians and surgeons: naval sailors' attitudes towards health, medicine and their own bodies remain virtually unexplored. Using official and personal sources, this article sketches a 'patient's history' of late-eighteenth- and early-nineteenth-century British ratings. Aiming to counterbalance Foucauldian interpretations, it highlights some of the ways in which individuals, even when apparently most powerless, confined in ships far from home, and controlled by rigidly disciplined institutions, could take responsibility for their health, successfully or otherwise, within, against or alongside the system. If the unprecedented administrative requirements of the French Wars strengthened and standardised top-down medical authority, they also brought opportunities for evasion and negotiation. This complicates established narratives of the relationship between modern medicine, the armed forces and power.