Morning brought a miserable drizzle, but the flattest seas we’ve seen since we left port. It was time to get to work. First order of the cruise was to get SUMO2, the five ton surface mooring buoy, off our back deck and into the water. The buoy is a wind-and-solar-powered, self-contained atmospheric and oceanic reporting station. It sits in about 4500 meters of water at the end of a 6000 meter line, which lets it drift around in a little circle. In addition to the meteorological instruments on the surface buoy, the line itself is instumented with a bevy of crazy devices measuring things like air/sea O2/CO2 flux, chlorophyll and nitrate concentrations, salinity, conductivity and turbidity. My favorite instrument in the stack is the ADCP, the Acoustic Doppler Current Profiler, which you point through a column of water and, as the name suggests, uses Doppler shift (and magic) to figure out which directions the water at different depths is moving.
The big challenge, of course, is getting this whole 3.5 mile long electronic pearl necklace – along with the 9000 pound steel BFA (Big Friendly Anchor) at its end – into the water without breaking anything.
The procedure that WHOI and OOI have developed entails marking the target site for the anchor, then drifting about six miles downwind/current before “pushing” the buoy out with the aft A-frame. We then motor slowly upwind to (and a little past) the anchor site letting out line and instruments. Once it’s all played out and stretched along the surface, the anchor goes overboard, sucking the entire string under and dragging the SUMO buoy along the surface like it’s trying to waterski behind a submarine.
It took the ship’s full complement of marine techs, engineers and scientists an entire day of staging for the deployment: hauling, bracing, lifting, securing and releasing, but SUMO2 went out without a hitch. As usual, your devoted correspondent watched from a safe distance. :)
Bug’s GoPro Video: https://youtu.be/9L47Gsn87lE
Pablo – Very interesting buoy, extremely clever deployment system