Abstract des Autors

Regarding the beach safety of surf zone users, this study aims to systematize the “Wave Knowledge” of the most efficient lifeguards, the surfing masters, by classifying the indicators relevant for recognizing spacial and temporal patterns and risk factors. This is evidenced by the proficiency in motor tasks essential both to the sport and rescuing in the surf zone: positioning in the lineup, catching waves/ returning to shore (when “Wave judgement” is needed). We start by reviewing the literature from Surf Sciences, followed by an analysis of manuals of Surfing as a sport. Then we researched the prospective procedures of experts in extreme surf conditions and observed behaviour of top surfers in competition, to put up a classification of the visual signs used (sea and swell, wind, tide, seabed configuration, currents, and details of breaking waves’ forms). Based on the acquired data, we built a Questionnaire to rank the “relative importance of the signals”, which surveyed 11 surf national champions/ coaches (male/female practitioners with over 15 years’ experience). Results show that experienced surfers evaluate all elements of the “waves-currents system”, although the location, type and intensity of maritime currents (except under conditions of small waves), and the swell characteristics (angle of arrival to coast, height, period) stand out as the most important. The importance of the signals varies according to the wave height and the wave break types. The respondents also attend configuration of seabed and coast profile in their evaluation. As for the surf quality, they consider the characteristics of the coastal wind and temporal characteristics of the tides. For the strength of the surf and the take-off point, the focus is on sections and wave face profiles (slope, thickness).