This dataset contains raw CTD (conductivity, temperature, depth probe) data for stations conducted during the cruise M210 in 2025 in the Atlantic Ocean. The goal was to observe the extent of water masses emitted from the Rainbow hydrothermal field and other sites along the Mid-Atlantic Ridge. For this purpose additional sensors were mounted to the CTD system: a Seapoint turbidity sensor, a custom-built Eh sensor (voltage channel 6) and for some stations an custom-built H2 sensor (voltage channel 7), the later two manufactured by the Max-Plank-Institute for Marine Microbiology Bremen. The two self-built sensors were untested and uncalibrated, therefore extreme caution should be used when interpreting their results. CTD stations were executed as normal vertical casts or as repeated up- and downcasts during slow ship travel creating a zig-zag-like pattern (tow-yo deployment). Additionally, data with the raw, unprocessed position data from a Posidonia acoustic underwater position tracker and the ships navigational system are supplied as well as scans of the handwritten deployment protocols. The acoustic tracker was mounted at the CTD rosette for most of the stations.