During SO216 the 12 kHz Simrad EM120 multibeam system of RV Sonne was used. This system works with 191 beams, where the maximum total angle of the emission beam is 150° across track and 2° along track. To obtain a high data accuracy, however, lower beam angles across track have been used (either 120° during transits or 90° within the main working area). Furthermore, the system was calibrated to allow correction of the ship's motion. Twice a roll and pitch calibration procedure was started. In addition, three water sound velocity profiles were recorded to correct the raw EM120 data. See 'Other version' for the data in GMT (Wessel & Smith, 1995) grid format (12.8 MB).