Multibeam bathymetry raw data using the ship's own Kongsberg EM 122 multibeam echosounder was almost continuously recorded during RV SONNE cruise SO273. Data was recorded on 28 days between 2020-03-07 and 2020-04-06. This dataset contains a survey in the Indian Ocean towards and in the area of the Southwest Indian Ridge and Eric Simpson Fracture Zone (north of the Prince Edward Islands). In addition, this dataset contains transit data in South East Atlantic Ocean. The approximate average depth of the entire dataset is around 4400m. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus SVP files are added to this dataset. However, also data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather excellent since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress, D. W., and D. N. Chayes, MB-System: Mapping the Seafloor, http://www.mbari.org/products/research-software/mb-system/, 2023).

These data should not be used for navigational purposes.Data publishing was realized by Daniel Damaske, MARUM - Center for Marine Environmental Sciences (University Bremen).