Multibeam bathymetry raw data using the ship's own Kongsberg EM 712 multibeam echosounder was not continuously recorded during RV MARIA S. MERIAN cruise MSM99. Data was recorded on 16 days between 2021-02-26 and 2021-03-19. This dataset contains 13x survey lines (occasionally with some line crossing perpendicular to the track) in the Baltic Sea and Gulf of Bothnia. The approximate average depth of the entire dataset is around 150m, ranging from 280m to 22m. No ancillary sound velocity profiles (SVP) files from the cruise are added to this dataset. Data analysis of the multibeam raw data revealed that SVP has been changed several 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 good since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress et al. 2024, https://doi.org/10.5281/zenodo.6302801).

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