As revealed by John Armstrong, coastal shipping was vital to Britain’s Industrial Revolution: it was a system of mass transport for coal, grain, and myriad other goods that long predated railways and canals. Despite this, we know little about how it functioned. This paper examines some fundamental characteristics, namely ship speeds, times spent in port, and trade patterns, to examine its effectiveness long before Britain’s industrialisation. Local customs records provided data covering thousands of recorded departures and arrivals of coasters. These data are analysed using a geographical information system and panel-data analysis. Methods are described and new insights given. While seacoasts boasted opportunities, observed coasting vessels exhibit severe timing irregularities and clearly operated in very challenging seas where delays and troubles were to be expected.