St Mary's Sound (CCO station 113) is an inshore coastal wave monitoring site at 49.8912°N, 6.3125°W. It’s part of the UK’s regional Coastal Monitoring / Channel Coastal Observatory network, placed to characterise nearshore wave climate for flood risk, erosion studies, coastal engineering and local forecasting. These stations commonly use a directional wave buoy (often a Datawell Directional WaveRider class) and report significant wave height, wave period (peak/mean) and wave direction; many also report sea temperature and, where fitted, nearby meteorology.