Low-crested detached breakwaters, vital for coastal protection, face scour challenges due to wave-structure-seabed interactions. This study advances the understanding of scour near detached rubble-mound breakwaters. Using a 3D mobile bed physical model at the University of Porto, various hydrodynamic conditions and breakwater geometries were explored. Scour predominantly occurred in the trunk section, with a distinct pattern in the seaward roundhead quadrant. Notably, the scour-accretion boundary was dynamic, dictated by prevailing maritime conditions. Peak wave period significantly influenced scour depths, emphasizing the need to incorporate realistic sea conditions into existing scour depth formulations for coastal protection structure design. Interestingly, plunging breaker phenomena were absent, challenging conventional assumptions and underscoring the complexity of scour dynamics in detached breakwaters. This research contributes to better-informed coastal protection strategies and highlights the importance of considering wave characteristics in scour depth assessment and design.
