Dispatch 24: Mooring D Recovery     Print

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Mengnan Zhao

October 11, 2015

Today was our final mooring recovery – Mooring D at 74N, 140W. The recovery started early this morning, around 8 am. Low temperatures of around -13C and the fact that we were in the southeastern basin, where the ice is solid and extensive, meant a challenging day for mooring recovery. After Rick located the mooring position with acoustic triangulation, it took a while for the Louis to steam back and forth to break the sea ice cover around the mooring. With the help of Captain Anthony Potts, First Officer Scott Kelly and Leading Seaman Vince Mullett’s great maneuvering skills, the ice surrounding the mooring was soon reduced to small manageable chunks. Once Rick sent the signal to the acoustic releases to let go of the anchor, we spotted the top floatation sphere almost immediately.

The swiftly drifting ice chunks made the mooring recovery somewhat more adventurous than in the open water. There were a few times when the wire over the side became stuck in the edge of the ice chucks. When this happened, we had to stop pulling in the wire, adjust the ship position and turn on the compressed air bubbler system to release the wire from the ice. At the final stage of the mooring recovery, when the 50 floatation glass balls were hoisted out of the water, they were tangled together with ice chunks. Officers on the bridge immediately reminded the crew on deck to beware of falling ice chunks. I couldn’t see clearly from up on the bridge, but later Jeff and Andy told me that one of the glass balls exploded due to the high pressure at those great depths (over 3800 m). It would be replaced for the redeployment tomorrow.

The mooring recovery gave Chris extra time to process his water samples (the mooring recovery/deployment and the rosette casts cannot be done at the same time) and he was also packing up water from station CB11 at 80N, 150W from 3000 m depth as a gift to Emma – a 6-year old girl fighting brain cancer who has a wish to see the deepest water from the Arctic Ocean. We’re thinking of you, Emma!