This paper provides details of an in-depth investigation into how racing sailors use information displays and devices, and shows that these devices act as communication loci and instigators of action. We present a brief summary of the ways that technology has pervaded the environs of sailing yachts, and analyse how this has affected the activities of the crew and altered the relationship between the sailors and their environment. We introduce a taxonomy of information processing levels that allows us to understand what information is currently presented and in what form, and provides a basis for us to consider future developments in the field. We then look in more detail at two example systems developed and deployed on a racing yacht, and consider their impact. They are analysed from the perspective of assisting people to improve their performance in training and in race situations, and the differences between the frenetic race around a course for 2-4 hours that is the standard race i...