Data acquisition was performed using a multibeam sonar system Simrad EM12-S. Raw data are delivered within Simrad current multibeam vendor format.Raw multibeam sonar data, format SIMRAD EM12-S (.all). SIMRAD raw data can be processed i.e. with the software packages CARIS HIPS/SIPS, Caraibes or with the open source software package MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/).Data are unprocessed and may contain outliers and blunders and should not be used for grid calculations and charting projects without further editing.