During the second half of the eighteenth century the shipping industry of the port of Liverpool continued to expand, as it had done since about 1660, as the port’s trade increased and became more diversified, both geographically and in terms of the commodities which it handled. Though the surviving statistical evidence is not entirely reliable and statistics produced at different times during the period are not strictly comparable with each other, there being, for example, no system of general ship registration before 1786 from which statistics of vessels owned within the port could have been calculated, it does appear that during the second half of the eighteenth century the amount of shipping owned within the port more than doubled, if not trebled. In 1751, 220 vessels were reputedly owned there, while on 30 September 1793, 606 vessels were officially on the Liverpool shipping register. Several thousand vessels were owned within the port at different times and for varying lengths of time during the period under review, for example, in the period from August 1786, when the system of general ship registration commenced, to December 1799, 1,571 vessels were either registered for the first time under the 1786 Ship Registry Act at the port of Liverpool or, having been purchased by Liverpool owners, were transferred to the Liverpool register from the registers of other ports. Clearly, opportunities for employment as ships’ captains were considerable. Indeed, such was the size of the Liverpool shipping industry in the second half of the eighteenth century that more than 2,000 individuals found employment as such, including several—possibly between 100 and 150—who were Catholics, though a precise figure is impossible to calculate on account of the difficulty of identifying captains who were of this faith.