The Teledyne Underway CTD was operated in tow-yo mode: the winch brake is disengaged and the probe is in approximate free-fall at 4m/s to 1m/s vertical speed collecting data for a cast. Then the brake is engaged and the probe is hauled in until it is within 10m horizontal behind the vessel at the sea surface. The winch is then disengaged and the next cast starts. A straight section is collected with the same probe in the water. At the end of the section, the probe is recovered. The data is recorded internally on the probe and only read out once the probe is back on deck. In addition to a test deployment, one long transect across the Georgia Basin northwest of the island of South Georgia was collected on PS133.1 in November 2022.