By the late eighteenth century, ‘national characters’ were understood as encompassing peculiarities in language, religion, ‘manners’ and forms of social organisation, as well as physical traits like skin colour or assumed fitness to a specific climate, and the effects of climate itself on human nature. This section explores how naval officers’ preconceptions on these matters, and the resulting recruitment policies, were shaped and changed by wartime interactions, shipboard disciplinary models, and the necessities of the service.