The raw multibeam sonar data in SURF format are compressed with ZIP. One dataset contains a measurement period not exceeding eight hours. SURF data files can be processed using the software packages CARIS HIPS/SIPS or with the open source software package MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/). The source code for an application programming interface (API) to read and write SURF data is released by the Hydrosweep manufacturer Atlas Hydrographic, Bremen, and published under the GNU GPL.