recovery of S6A early Friday morning went smoothly. I spent almost the entire morning on the bridge,
a lot of it outside, hoping that I would be the first to see something. The weather was sunny and it felt warm on the
sunny side of the bridge. Even though
the barometer was on the low side there wasn't much wind. After SA6 we took off southeast towards
We reached the vicinity of C3 around 1600 on Friday. Bob has been pleased about all the recoveries to date, but quite ready to find out what has become of the WHOI current meter moorings. These are very different from the SIO acoustic moorings. The ARPs sit on the bottom with the sensor on a tether just above them. They might take a long time to come up, but once they are caught with the grappling hook it is relatively simple to get them aboard. On the other hand, the current meter moorings have multiple instruments stretching from the bottom to near the surface. The release is not by a burn wire, but by a mechanical device. Once we found out that C3 was there and responsive, we did a CTD cast, which continuously measures conductivity, temperature, and pressure from the surface to near the bottom. This instrument is mounted on a large cylindrical rack in the Baltic Room. It has a sensor to keep it from hitting the bottom, and is covered with bottles that go down open at both ends and are closed at different depths. These water samples provide a calibration of the salinity, which is calculated from the conductivity, temperature, and pressure. The instrument is put out of the Baltic Room to the starboard. The huge door is opened, then a crane picks it up and moves it out the door. The instrument is kept just below the surface for awhile to equilibrate, then lowered slowly down. The cast takes awhile to complete and I managed to get dinner during this process.
I wanted to film the entire retrieval of C3, but from the TV screen in Bob's office I could see that the ship was moving back and forth rapidly. I found out that they first wanted to see if they could locate the top of the mooring with the ship's sonar, as little blibs compared with the bottom signal. This was apparently successful. There is a mooring that they could not get to release last cruise, and if we can locate the top part of it by this means, we can try to drag for it later. Finally the ship got into position and the mooring was released. It came up fast. The floats are much bigger than the ARP floats; no problem seeing them. The mooring is almost the same length as the depth, so over 700 meters. There is an yellow float maybe four feet in diameter at the top, then some instruments, then an orange float, then instrument after instrument, a cluster of smaller yellow floats and more instruments, and finally the release mechanism which had been connected to the heavy bottom anchor. However, they don't pick it up in that order. They grapple for the cluster and get that on board. Then the ship moves very slowly ahead, just fast enough to keep the cable stretched out behind. As each instrument comes on board, the mooring winch line is reattached to the next part of the cable and the instrument removed and taken inside, where Dick puts them in a saltwater bath for calibration. The big yellow float was last. It took six or seven people an hour and a quarter to get it all on board. Scott was the deck boss, Jamey running the winch, Jason and Zan were handling lines and keeping a record of each part of the mooring as it came aboard, and Brian, Skip, and Rick helping Scott at the stern, where the guard rail had been taken away and they had to wear safety lines. Bob was up in the aft wheelhouse with Captain Robert. It's a very specialized job working with moorings and requires a lot of teamwork.
C3 we headed for the next WHOI current meter mooring, on one engine as the
engineers were changing the oil on the other one. We were entering
spite of the iceberg, the CTD cast went fine.
Afterwards they launched a WHOI Solo float, and I could go out on the
main deck to take pictures because no cranes were involved. This is one of the
four instruments that Dick and Bob uncrated and turned on in the AGUNSA
With two almost perfect recoveries we were on our way to C1. The SIO group will be busy for the rest of the trip scanning through their year's accumulation of data. The two Debs were on the bridge looking for whales whenever the visibility was good enough.
At C1 the CTD went down and up fairly rapidly, because it is much more shallow there, only 450 meters. We used the same method of locating the top of C1 by moving back and forth over it with the ship's depth detector. The two blips caused by the big red and yellow floats showed up clearly above the bottom scan. However, the mooring would not release after an hour of trying, and it was judged a little rough for dragging for it. So we headed for the SIO mooring A9, which is a little less than two hours away. A9 is just south of Adelaide Island in the northern part of Marguerite Bay, at latitude -67º 54.4999′ and longitude -68º 23.003′. As we steamed deeper into the bay there were some terrific views of land and icebergs. During the late afternoon humpbacks were seen ahead breaching and showing their flippers. The ship passed right beside them while they carried on their show. I managed to miss this; I should have known that something was up when several individuals sprinted up and down the hall so fast I couldn't see who they were. Deb Glasgow took many wonderful photos in which the whale fills a major part of the image.
I took a walk on the 02 deck after dinner. It is the only level at which one can go completely around, although I didn't go all the way forward because of the wind. I hope my photos do it justice. Lots of people gathered on the bridge as we approached the mooring. Three minke whales were spotted “lunge feeding,” this time I saw them too.
S9 was at 687 meters in a bit of a hole. There was some concern because the more shallow the mooring, the more likely that the release burn will fail, for reasons that are not well understood. After three burns John Hildebrand down in the lab thought it might have started up. He had the mate reposition the ship a little closer so the mooring would be on the starboard side and just a little ahead. Soon he was giving estimates of “slant distance”. The estimates went from 500 meters to 200 to 150. The two yellow floats popped up exactly where he predicted. The deck crew got it on board and we steamed back to C1 to drag for it first thing Sunday morning.
Sunday was a very long day. Scott was able to communicate with the release and send the release command, but nothing happened. The decision was then made at to drag, but it took two hours to get the deck set up. There were signs posted all day that the 01 deck was off limits because of the dragging operation, and I thought better of going on the 02 deck for the same reason. The bridge was the best place for me to see what was going on, because I could hear the radio communications from the main deck and could see the stern in the TV display. As we steamed very slowly in a elongated U around the mooring, the cable was let out, first a weight, then at 300 m a grappling iron, at 600 m another grappling iron, at 900 m another weight, and finally a pinger at 975 m. About 1500 m of cable were laid out. The pinger could give us an idea of the depth of the rest of the cable. The hope was to get the cable down on the bottom and wound around the mooring, then to move off, tightening the cable and breaking off the mooring as close to the bottom as possible. C1 is at a depth of 450 m, but the terrain is extremely rough down there, and it is located on the side of a large bump. As we finished the U the cable sawed though the mooring wire. The big yellow and orange floats surfaced soon afterwards. Many eyeballs were looking for the cluster of smaller yellow floats (sometimes called “hardhats”, because of the appearance of the protective coverings). When these didn't appear, they got the drag line back on the deck.
At this point the Captain opened the galley early so the deck crew could grab some lunch before starting the recovery of the part on the surface. It snowed all afternoon and at times visibility was quite limited. We had drifted out of sight of the large floats, but thanks to GPS you can find a needle in the haystack of the ocean, if the wind and currents haven't taken it too far. Around that time I saw some whales spouting, but there was no expert on the bridge at the time, plus the ship was turning, so I don't know what kind. My report, sketchy as it was, went into the log.
After lunch we approached the big floats and brought on board everything attached to them. The mooring line had broken just above the smaller floats, so most of the instruments were recovered, but there were still some between the release mechanism and the small floats. So at 1400 the ship was positioned for the second drag. We were hopeful that the drag line would be close enough to the bottom this time to catch what was left of the mooring. Many eyeballs were looking again but nothing came up as the cable was brought back in. Finally the ship steamed back to the mooring site and Scott talked to the release. If the cable had cut the small floats off, the release would have been lying on its side and would have so indicated, but it was still vertical, meaning that the lower part of the mooring is still intact up to the small floats.
I went down to dinner right at the last minute, and Bob finally showed up also. However, I was just started on a piece of pineapple upside down cake when the mate phoned down to the galley to tell me that there were whales. I ran up three flights of stairs and got there in time to see two humpbacks carrying on quite close to the boat. The mate said he didn't want any guilt trips for not letting me know, and I was very appreciative.
have abandoned C1 for now, leaving the release enabled. We are headed for a
more sheltered location so that the main crane can be used to transfer the two
Zodiacs from the 01 deck to the main deck during the night. Then we will check
on the state of an older current mooring with the sonar, and finally head far
south to the head of