This record describes multibeam echosounder data collected on RV Investigator voyage IN2025_V02, ' SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania ' which departed Hobart on the 26th March and returned to Hobart on the 14th April 2025. The EM2040 MKII provides a 0.4 degree by 0.7 degree angular resolution. The echosounder's nominal frequency is 400 kHz (with a range of 200-700 kHz) and it operated in dual swath mode. This system was only operated in water depths typically shallower than 250 m. Data are stored in *.kmall raw format for bathymetry and backscatter and *.kmwcd format for watercolumn backscatter at CSIRO. There are 31 files totalling 6.88 GB of raw data and 31 files totalling 69.1 GB of watercolumn data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.kmall format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report.

This record describes multibeam echosounder data collected on IN2025_V07, 'SOFS recovery voyage' which departed Hobart on the 1/7/2025 and returned to Hobart on the 6/7/2025. This voyage was staffed by only one GSM team member, thus 24 hours acquisition was not possible and there may be gaps in the data record. The EM2040MK2 provides a 0.4 degree by 0.7 degree angular resolution. The echosounder's nominal frequency is 400 kHz (with a range of 200-700 kHz) and it operated in dual swath mode. Data are stored in *.kmall raw format for bathymetry and backscatter and *.kmwcd format for watercolumn backscatter at CSIRO. There are 22 files totalling 5.91 GB of raw data and 22 files totalling 66.0 GB of watercolumn data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.kmall format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data has had outliers removed. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report.