The trial was conducted using the standard RMS water column probes with the 25mm and 75mm probe holders; both worked well and provided reasonable A-Scan echoes and a corresponding C-Scan. Notice in the C-Scan image there are several dark blue areas. These relate to weld of internal supports, scattering the sound thus reducing the amplitude of the reflected signal.
A variety of scans with different resolutions was conducted, all with virtually the same results. In this application, it is recommended that the scanner speed is slowed down to around 300mm per second, too quick, the water column wouldn’t stabilise. Also to maintain a reasonable water seal, a high tension on the probe holder is required meaning that a standard 730mm/s travel speed will result in vibration. Several scans were conducted during the 2-3 hours of use with a maximum duration of the RMS on the surface of 30 minutes.