On 1 July 1677, the Danish navy won a decisive victory over a superior Swedish fleet in the bight of Koge. This success was partly due to trained seamen, who had been recruited in Amsterdam and manned the Danish men-of-war. Another professional seaman was the admiral Cornelis Tromp, who had been employed by the Danish king, not only for his skill and talent as a naval commander, but also because his very presence in Baltic waters had a deterrent effect on the Swedes. This article assesses these experienced seamen and argues that they were skilled craftsmen, who were just as important a resource for the success of a navy as big ships and heavy guns. So important, in fact, that the naval authorities were willing to pay relatively high wages to secure the expertise of professional seamen. Introduction: Current understanding of the markets for seamenThis article attempts to examine some strategic considerations in manning the Royal Danish Navy during the late seventeenth century, and to get a better understanding of who the seamen were that manned European navies of this period. It seeks to demonstrate that the actual handling of large square-rigged vessels was a very complicated process requiring skilled men with years of experience, and that such experienced crew were prized in times of war. At the tactical level it will also be argued that good