Improvements in the productivity of ocean shipping between 1600 and 1850 have been identified and discussed by D.C. North, and his analysis has been largely confirmed with respect to the colonial North American trades by J.F. Walton and G.M. Shepherd. The last two writers agree with North that there was little technological innovation in the vessels themselves except for some reduction in manning levels. This reduction in manning, they argue, was to be attributed less to economies of scale than to a diminution in the carrying of armaments consequent upon the suppression of privateering and piracy. Much of the improvement in productivity, they found, was the result of quicker turn-round time, the standardisation of packages, and other reductions in inventory costs. It is perhaps worth adding that as vessels were deployed more efficiently the ratio of sea time to port time would be increased, and this itself would improve the speed at which members of the merchant community could communicate with each other, to the further benefit of productivity.

Neither of the authorities cited above discusses the part the master mariner played in the improvement in the productivity of shipping, an improvement which was to gather pace in the nineteenth century when technological change became extremely rapid after an age of relative stagnation. This article examines one factor that played a part in improving the efficiency of master mariners, namely the proliferation and wider circulation of printed guides to assist them in the manifold duties that were devolved upon them by ship owners and charterers.