This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2023_E03, titled "Trials & Calibrations", which was segmented into 3 legs, departing Hobart on September 13 and ending in Sydney on September 30, 2023. Leg 1 (Hobart to Hobart) took place between 13-16 Sep, Leg 2 (Hobart to Hobart) between 16-25 Sep and Leg 3 (Hobart to Sydney) between 26-30 Sep. The Simrad EK80 wide band transceivers (WBT) 38, 70, 120, 200 kHz and the EK60 split-beam GPT 18 kHz were calibrated during Leg 2 of the voyage. The calibration was undertaken at anchor in the Derwent Estuary on September 18, 2023 with the 38mm sphere deployed at 03:00 (UTC) and calibration recording conducted between 07:14 - 10:06 (UTC). The EK80 WBTs were calibrated using default settings for only CW modes. Due to line snagging issues under the hull and resulting time limitations, no calibration was undertaken for the 333 kHz or for the remaining EK60 GPTs. The results of the calibration were not applied immediately to the EK80 (pending further onshore analysis). All frequencies were logged sporadically for the extent of the voyage. The frequencies were set to passive for periods during the voyage when conducting other system calibrations or during shallow water mapping when interference was noted on the mapping system (EM710) from the 70 and 120kHz frequencies mainly. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 519 files totalling 45.6 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.