8 February
Today we continued the XBT drops. An XBT (Expendable Bathythermograph – aka Bathys) is a small probe that is dropped over the side of a ship. As it falls through the water, it measures temperature. Small wires transmit the temperature data back to the ship where it is recorded for further analysis. We can plot temperature as a function of depth to create a temperature profile of the water.
The data from them will be made available to the Antarctica Ocean science community and join an international database of thermal profiles of the upper 500m of the ocean.
This science activity is on behalf of NZ Antarctic Science Platform.
Since departing Devonport, the ship’s crew have been dropping the XBT every 6 hours. Starting today, we began dropping them every hour, on the hour, as we travelled west along the Ross Ice Shelf. We passed Mt. Terror and Mt. Erebus, and stopped once we reached the point where Ross Island curves into McMurdo Sound.
The Combat System Specialists (CSS), who are responsible for performing the XBT deployments, are the primary crew members tasked with this job. There are only four CSS personnel on the ROA, and we were asking them to complete hourly drops for 26 hours—on top of their regular duties, which include watches on the bridge and other ship responsibilities. To help out, we enlisted two divers, along with myself, Peter, and Oscar. This brought the total to nine people, with three people required per drop. We organized into three teams of three, each working 4-hour shifts.
I had the 2300 – 0300 shift with the PO Diver and LCSS. The LCSS was gathering the data in the Ops Room, and the PO and I were on the quarter deck dropping the bathys. Between drops, we played a couple of games of UCKAS (a bit like Ludo) and then started watching the Chernobyl mini series, which we only got 2 episodes through.
he next day, the bathy shift was scheduled from 1200 to 1500. However, just before lunch, the bathy drop period was extended until 2000. It wasn’t ideal, but it wasn’t too bad either. The bathy crew had limited sleep but planned to finish before bedtime. To avoid impacting their sleep that night, most of the team stayed awake during the day and didn’t nap too much.
Then, just before dinner at 1700, we learned that we’d be working through the night again. I was scheduled for the 2200-0200 shift. The CSS team knew I hadn’t slept and kindly offered to swap shifts, covering the night for me if I did their standard 0600 drop the next day. After a bit of back-and-forth, we agreed—since I wasn’t doing the bridge watches or full days of work they were still handling on top of the bathy drops, it was easier for me to catch up on sleep. They explained that covering the night shift would be the only way they could sleep until 1200 the following day.
The hourly bathy drops stopped at 0300. I am tired.
-Sara