Raw multibeam bathymetry data collected in the wider polynya area around the Mertz glacier, East Antarctica on board the R/V Akademik Tryoshnikov during the austral summer of 2016/2017 as part of the Antarctic Circumnavigation Expedition (ACE). ***** Dataset abstract ***** An ELAC Nautik 3020 multibeam echo sounder with a 20 kHz transducer mounted on the hull of the R/V Akademik Tryoshnikov, was used to collect multibeam bathymetry data during the Antarctic Circumnavigation Expedition (ACE). This particular dataset was collected in the wider polynya area around the Mertz glacier, East Antarctica in the austral summer of 2016/2017. Bathymetry data were used live during the cruise to look for suitable locations where benthic trawling and remotely-operated vehicle deployments could take place, rather than to undertake specific bathymetric surveys. This raw dataset is provided without calibration information for the surface sound velocity or instrumentation itself and should be used with due caution. ***** Original data collection ***** An ELAC Nautik 3020 multibeam echo sounder with a 20 kHz transducer was mounted on the hull of the R/V Akademik Tryoshnikov. The instrument was connected via a serial port connection to a Windows PC running XP, in the acoustics laboratory. Data were saved automatically to the Network Attached Storage on an hourly basis by sharing the data directory on the local Windows PC. The transducer had 256 beams and were normally operated with a maximum swath angle of 140 degrees. During this cruise, 90 degrees was used when there was seen to be a rocky seabed and 120 degrees when the seabed was sandy. Many of the other settings were changed automatically in the software according to the conditions at the time (i.e. pulse repetition rate was lower in deeper water and higher in shallower water). The relevant settings were captured in the raw data files. For more information see the cruise report (Walton and Thomas, 2018; DOI: 10.5281/zenodo.1443511). The instrument was operated by Hydrostar software on the same Windows PC. Data files generally contain a few hours' data and were automatically saved by the software. Files are provided in Elac/SeaBeam XSE format which can be opened by MB-System software (Caress and Chayes, 1993). A Trimble GPS feed was provided to the Hydrostar software, geolocating the bathymetry data, however the cruise track has been quality-checked (Thomas and Pina Estany, 2019; DOI: 10.5281/zenodo.3260616) and this should be used in preference to the position data that comes as part of the files in this dataset. No information is available regarding any specific calibration work that was done to obtain surface sound velocity, or regarding that of the instrumentation. Verified physical oceanography data including water-column salinity are available in the dataset from the on-board CTD (Henry et al., 2019; DOI: 10.5281/zenodo.3247384) which was deployed in the vicinity of the multibeam operation. ***** Data processing ***** No processing of the data files has been undertaken, but the files have been transferred from Network Attached Storage on-board, to object storage. File checksums remained intact. ***** Quality checking ***** No quality checking of the bathymetry dataset has been undertaken. Quality-checked salinity and cruise track data are provided in related datasets (DOIs 10.5281/zenodo.3260616 and 10.5281/zenodo.3247384 respectively). ***** Standards ***** This dataset is provided as it was collected in standard Hydrostar-format files. Metadata is provided as required for submission to NOAA’s National Centers for Environmental Information and the co-located IHO Data Center for Digital Bathymetry. ***** Further information for interpreting the data and using the dataset ***** Timescales: Timescales are not relevant to this dataset. Aggregation to lower temporal resolution: This is not applicable to this dataset. ***** Dataset contents ***** - lineYYYYDDmonHHMMSS.xse, data file, proprietary format - location.hydrostar, ancillary file, ASCII - data_file_header.txt, metadata, text - README.txt, metadata, text ***** Dataset contact ***** Jenny Thomas. Swiss Polar Institute, Switzerland. ORCID: 0000-0002-5986-7026. Email: jenny.thomas@epfl.ch, jt.sciencedata@gmail.com ***** Dataset license ***** This raw multibeam bathymetry dataset is made available the Open Data Commons Attribution License (ODC-By) v1.0 whose full text can be found at https://www.opendatacommons.org/licenses/by/1.0/index.html ***** Dataset citation ***** Please cite this dataset as: Swiss Polar Institute. (2019). Raw multibeam bathymetry data collected in the wider polynya area around the Mertz glacier, East Antarctica on board the R/V Akademik Tryoshnikov during the austral summer of 2016/2017 as part of the Antarctic Circumnavigation Expedition (ACE). Version 1.0) [Data set]. Zenodo. DOI Please use the DOI when you cite this dataset.