A manual on using a PC on board a boat. It guides the reader through the process of choosing a PC as well as suitable software for tidal calculations, route planning, chart plotting, performance analysis, weather information, communications and the Internet. The authors demonstrate how using a PC can make life easier on board and take the slog out of navigational calculations. There is information on installing and looking after a PC on board, along with discussions of power supplies, interfacing and upgrading.