Improving surfing conditions with floating wave filters

The sport of surfing has increased tremendously in popularity in the last decade and surf breaks around the world are progressively getting overcrowded with surfers. This overcrowding is an annoyance to surfers themselves since surfing is an individualistic sport, one wave for one surfer. This coastal problem has been addressed by science through Artificial Surfing Reefs (ASR), however these are highly ambitious projects that haven’t been perfected. This thesis introduces and alternative way to approach the problem, which is to improve the conditions at the surf breaks that already exist. The objective of this thesis is to introduce Floating Wave Filters (FWF), which are floating structures anchored to the sea bottom that aim to block short-period waves and transmit long-period waves in order to improve surfing conditions. Short-period waves are generated by local winds, their periods do not exceed 4 seconds and wave heights are less than half a meter. Long-period waves refer to swell waves, with periods longer than 8-10 seconds and variable heights. In general the preferred conditions for surfing are long-period waves, light offshore wind or no wind and the right tide for the particular surf break. When the wind at the coast is onshore the conditions for surfing deteriorate for two reasons. The first reason is that waves will tend to spill instead of plunge and surfers prefer plunging waves. The second reason, which FWF address, is that as wind blows toward shore, short-period waves are formed and these waves mix with the long-period waves to tamper or ruin surfing conditions. The thesis gives a general description of the sport of surfing, discusses the role of surfing in Integrated Coastal Zone Management, describes coastal wind patterns, characterizes good surfing waves and gives the guidelines to perform an experiment with FWF in a wave flume.CoMEM - Coastal and Marine Engineering and ManagementHydraulic EngineeringCivil Engineering and Geoscience