In the days of sail the cost of sea transport was principally the cost of paying and feeding a crew. During the seventeenth century the Dutch had led the way in operating ships that needed small crews in relation to the cargo they carried, and the English had followed their example, when they could, by using captured Dutch-built ships. In the eighteenth century, however, English shipbuilders made their own way towards operational efficiency. The clearest way of measuring their success is by looking at the gradually decreasing ratio of crew to tonnage; that is, to use the somewhat artificial concept of “tons served per man.” The picture can be drawn with some accuracy from 1726 onward, when this sort of evidence can be extracted from the records of “Seamen's Sixpences” but to point the contrast it is as well first to glance back briefly at the manning position in the previous century, so far as this is possible.

It is clear that in the early decades of the seventeenth century, ships going southward from England - to Spain and Portugal, the Biscay coast of France, the Mediterranean and the East Indies - were very heavily manned. These vessels had to defend themselves against the corsairs who were ready to prey without limit on English shipping in the Mediterranean and off the Atlantic coast of Europe, until naval expeditions began to curb their eagerness. The guns which ships carried might well have to be used, and it was a good thing to carry a crew which could at least man a single broadside. But as the dangers declined, so crews were reduced gradually towards levels determined by the requirements of serving the ship; curiously enough, the number of guns carried was little if at all reduced, though they could no longer be fully manned. In the thirties, the English ships going to Cádiz and Málaga for wine and fruit carried crews averaging one man to 6.7 tons; in 1686-1687 the corresponding figure is 7.7 tons.