Dispatch 13: We Came Back for You, Mooring B!
Annika Margevich
September 27, 2023
Dispatch 13: We Came Back for You, Mooring B!
Today, we recovered Mooring B which was deployed on last year’s JOIS/BGOS cruise! We began around 5 am when we arrived at the location where Mooring B had been deployed last year. Once we got within a kilometer or so of the mooring, we used a deck box to communicate with the instrument. The deck box sends out a signal, and if the mooring is within range to receive the signal, you will hear a ping back on the deck box. Once you receive this ping information from a few different locations, you can pinpoint the mooring’s precise location. We found that the mooring was a little over 400 m from where we recorded it had been deployed last year. With this understanding, we got the ship closer to the mooring and once everything was all set, we sent a release code from the deck box to the mooring. The mooring is designed such that there is a 3800-meter line with a weight on the bottom, a buoy on the top, and instruments along the line. In between the bottom-most instruments and the weight, there are two releases. The releases hold the line, instruments, and buoy to the weight. When a release receives the release code from the deck box, it knows to let go of the weight such that the buoy can pop to the surface (leaving the weight behind), and we can recover everything attached.
After the release code was sent, we were all up on the ship’s bridge looking through binoculars to spot the big yellow buoy pop to the surface. It was kind of foggy, so we were thinking we’d really have to be looking hard to see it. However, I glanced out the window on the starboard side (the right side) and, poof, there it was, a big yellow ball bubbling to the surface right next to the ship. It must have been ready to come home! Once we had eyes on it, the captain maneuvered the ship such that a crew member could be lowered in a cage on a crane to hook the buoy so that it could be hoisted on deck. From there they lifted the buoy on deck and removed it from the line. They then worked section by section, alternating reeling in line with stopping to remove, clean, and stow the instruments. We are excited to peek at the data and see what Mooring B has been up to for the past year since we last saw them!