This record describes shallow multibeam data collected on RV Tangaroa voyage TAN2021_V01 (NIWA TAN2113), which was carried out on a contract to the CSIRO MNF from 9th November to 4th December 2021. The voyage had two objectives, which were to recover 27 Ocean Bottom Seismometers which had been deployed around Macquarie Island on IN2020_v06, and complete multibeam and sub bottom profiler mapping along the crest of the Macquarie Ridge and collect new multibeam data during transits. The Kongsberg Maritime EM2040 was used to obtain swath bathymetry, backscatter, and water column data in shallower water (20 - 300 m), using Kongsberg Seafloor Information System (SIS) version 4.3.2 acquisition system. The EM2040 is a single RX system, with 256 beams (or 576 beams in dual swath mode), yielding 400 soundings (or 800 soundings in High Density mode). Water column data, which show the received amplitude of the entire water column for each beam, were recorded simultaneoulsy with the multibeam echosounder data. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 129 files totalling 11.6 GB of raw data in this dataset. There are 129 files totalling 152 GB of water column data. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Raw data (*.all files) were processed using QPS Qimera v2.4.2 for bathymetry and QPS Geocoder Toolbox (FMGT) v7.10.0 for acoustic seafloor backscatter. *.gpd files were generated by Qimera for each *.all file after editing. The quality of the bathymetry data was examined, and surfaces of varying resolution generated for each survey area. The data were cleaned in both 2D and 3D manually. Where appropriate a medium spline filter was used. Gridded bathymetric surfaces were projected in WGS84 / UTM zone 57S (EPSG:32757) coordinate reference system at varying resolutions. Bathymetry datasets were collated, and maps produced in ArcGIS Pro v2.8.3. Water column data files (.wcd) were not processed onboard. Additional information regarding this dataset is contained in the "NIWA Voyage Report 2022007WN.pdf". The report is available from Geophysical Survey and Mapping (GSM) group at CSIRO upon request.

This record describes deeper multibeam data collected on RV Tangaroa voyage TAN2021_V01 (NIWA TAN2113), which was carried out on a contract to the CSIRO MNF from 9th November to 4th December 2021. The voyage had two objectives, which were to recover 27 Ocean Bottom Seismometers which had been deployed around Macquarie Island on IN2020_v06, and complete multibeam and sub bottom profiler mapping along the crest of the Macquarie Ridge and collect new multibeam data during transits. The Kongsberg Maritime EM302 was used to obtain swath bathymetry, backscatter, and water column data in deeper water (down to 7000 m), using Kongsberg Seafloor Information System (SIS) version 4.3.2 acquisition system. The EM302 is a 1 TX by 2 RX system, with 288 beams (or 576 beams in dual swath mode), yielding 432 soundings (or 864 soundings in Dual Swath mode ). Water column data, which show the received amplitude of the entire water column for each beam, were recorded simultaneoulsy with the multibeam echosounder data. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 201 files totalling 25.2 GB of raw data in this dataset. There are 200 files totalling 43.8 GB of water colomn data. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Raw data (*.all files) were processed using QPS Qimera v2.4.2 for bathymetry and QPS Geocoder Toolbox (FMGT) v7.10.0 for acoustic seafloor backscatter. *.gpd files were generated by Qimera for each *.all file after editing. The quality of the bathymetry data was examined, and surfaces of varying resolution generated for each survey area. The data were cleaned in both 2D and 3D manually. Where appropriate a medium spline filter was used. Gridded bathymetric surfaces were projected in WGS84 / UTM zone 57S (EPSG:32757) coordinate reference system at varying resolutions. Bathymetry datasets were collated, and maps produced in ArcGIS Pro v2.8.3. Water column data files (.wcd) consisting of 165 files, 31.1 GB, were not processed onboard. Additional information regarding this dataset is contained in the "NIWA Voyage Report 2022007WN.pdf". The report is available from Geophysical Survey and Mapping (GSM) group at CSIRO upon request.

This record describes sub bottom profiler data collected on RV Tangaroa voyage TAN2021_V01 (NIWA TAN2113), which was carried out on a contract to the CSIRO MNF from 9th November to 4th December 2021. The voyage had two objectives, which were to recover 27 Ocean Bottom Seismometers which had been deployed around Macquarie Island on IN2020_v06, and complete multibeam and sub bottom profiler mapping along the crest of the Macquarie Ridge and collect new multibeam data during transits. The Kongsberg Maritime TOPAS PS 18 Parametric Sub-bottom Profiler was used to acoustically image the strata and structure in the seafloors's shallow sub-surface. Sediment penetration can achieve 120-150 m in ideal conditions. Sub bottom profilers in general do not perform well with hard rocky substrates, water depths less than 150 m, steep and irregular terrain. The working area was subject to these limitations which made SBP data acquisition challenging and affected the resultant data. The data recorded in water depth greater than 4000 m at transit speeds when synced with multibeam acquisition was of little use as the time between pings was too long to maintain bottom lock. The transmitted waveform used was a linear frequency-modulated chirp (LFM) which was externally triggered with K-Sync to avoid interference with the EM302 and EM2040 multibeams. The frequency range of the chirp was from 2.0 to 6.0 kHz, with a chirp length of 20 or 15 ms or 50 ms for deep water. Transmitter output level was set to 0 dB and gain set to 0 dB and the high-pass filter was set to 1.0 kHz. The sub bottom profiler beam is stabilised for heave, roll and pitch via motion data fed from the PosMV. Beam steering was set to automatic. Raw data files were written in WGS 84 and SEG-Y files were written with UTM57S projection in the survey area and NZTM projection on transit. Data are stored in *.raw (123 files 3.82 GB) raw and *.seg (156 files 3.78 GB) segy formats at CSIRO. Additional information regarding this dataset is contained in the "NIWA Voyage Report 2022007WN.pdf". The report is available from Geophysical Survey and Mapping (GSM) group at CSIRO upon request.

This record describes the End of Voyage (EOV) data archive from the Marine National Facility (MNF) RV Tangaroa voyage TAN2021_V01, titled "Macquarie Island Voyage." The voyage was carried out on NIWA (National Institute of Water and Atmospheric Research, NZ) vessel Tangaroa, on contract to the CSIRO MNF. The voyage took place between November 9, 2021 and December 4, 2022 (NZST), departing from Wellington and returning to Wellington. For further information please refer to the voyage documentation links. Instruments used and data collected include: EM302 and EM2040 multibeam echosounders, TOPAS PS 18 Parametric Sub-bottom Profiler, Ocean Bottom Seismometers (OBS). The archive for the TAN2021_V01 EOV raw data is curated by the CSIRO National Collections and Marine Infrastructure (NCMI) Information and Data Centre (IDC) in Hobart, with a permanent archive at the CSIRO Data Access Portal (DAP, https://data.csiro.au/dap/), providing access to voyage participants and processors of the data collected on the voyage. All voyage documentation is available electronically to MNF support via the local network. Access to voyage documentation for non-CSIRO participants can be made via NCMI_DataLibrarians@csiro.au.