The CADMOS-S project was one of the first maritime archaeology programmes in Lebanon to use geophysical means of exploration. It was jointly funded, over two years (2015-2017), by the Honor Frost Foundation and the Centre National de la Recherche Scientifique in Lebanon. At the time of the inception of the CADMOS-S project, the CNRS-L had been conducting coastal bathymetry surveys on-board the CANA-CNRS research vessel with its main instrument, a multi-beam echo-sounder aimed at the geomorphological recognition of the coastal seafloor from -20 to -1000m. With these specifications, this device could only render limited service to underwater archaeological exploration. In the knowledge that the coastal seabed off the cities of Saida (Sidon) and Sour (Tyre) had been subject to limited prior exploration, priority was given to get a precise and extensive description of these underwater landscapes, a task the multi-beam could handle efficiently.