In Britain's wars of the 1740s Royal Navy press-gangs circulated throughout the Atlantic world attempting to force, or impress, British seamen into naval service. Sailors responded, often with the backing of Atlantic seaport communities, by mounting the most spectacular series of impressment riots in the eighteenth century. These disturbances showed that even while impressment helped to forge a common English-speaking Atlantic world, the institution also operated according to separate laws, customs, and traditions in individual regions of the Atlantic. Moreover, the seizing of men produced different consequences depending on the labor markets of particular seaports. Yet, if impressment riots in the British Isles, the West Indies, and North America did not always look the same, they often did share one common element: the presence of Admiral Charles Knowles. In the 1740s Knowles instigated the largest impressment riots in the history of Britain's Caribbean and American colonies. Indeed, the Boston Knowles Riot of 1747 was the most serious disturbance against British imperial authority in the mainland American colonies in the generation before the Stamp Act crisis. Together the Knowles riots and other acts of resistance against press-gangs demonstrated how dangerous forced naval service had become for Britain's Atlantic empire by the mid-eighteenth century.