Week 2

Sunday March 27, 2018

Week 2 – 170°W stations

  Current position: 67 36.5°S, 174 33.9°W

Winds: from the NNE at 40 knots

Heading for Station 18

When we left you last we were contemplating a weather map which we began calling “the grey eye of doom;” an extended pattern of storms with central winds broaching 50 kts and 20 ft seas. Threatened with as many as 5 days of untenable weather and sea states so early in our cruise, we headed southeast out of the path of worst of the weather to the 170°W ice edge.  

It was rather a shame to stop CTD casts just as a watch standers were getting the stride, but one positive aspect of the two day steam eastward was that it gave Rachel  L. (U. Alaska) the chance to take the UVP, which has been failing to charge, off the rosette. Upon opening it up, it was discovered that the recharger was unplugged. Perhaps the Velcro hadn’t been tighten enough or perhaps customs had taken it apart – who know? But at least we now have a working UVP - some of the products of which are displayed above.

 
Another positive outcome of our steam time was that John C. our omnipresent technical wizard fashioned a new design for the spigot “discs” that had for unknown reasons the unfortunate habit of spinning themselves into alignment with the pin and upon touching would snap open. The new design, printed on the ship’s 3-D printer are known as “tabs” (photo on left). They work on the simple assumption that the side with greater mass will always tend to hang down.

 

As we had found at start of our cruise at ~170°E, the shelf was not accessible. Our first attempted station at 71.5°S was aborted as strong winds out of the north relentlessly pushed ice into the space we had cleared for the rosette.  Half a degree further north we had better luck. Thinner ice pancakes and more open water gave us our first cast since Station 8 two days earlier.  A SOCCOM biogeochemical float (the Floating Falcon, see below) and an FSU ALTO float were successfully deployed, though in hindsight it might have been better to have waited until we had a completely ice-free station. We then continued our way northward up the 170°W line putting the rosette in the water every 30 nm (0.5° latitude) up to to 67.5°S.

 

Lauren F. drawing the Floating Falcon

Insignia. Images courtesy of E. Briggs

On Station 10, near the beginning of our run up 170°W, the primary oxygen and salinity sensors went out near the bottom. It took two replacements of the pump to eventually solve the problem. Another issue, which has been hounding us with the weather, is ship heave and roll resulting from confused seas and strong winds, which in combination the particular design of this rosette produces high-tension spikes. After much discussion over the last few days it has been decided that we will assess the situation on each cast. If, at any point, it is determined that stopping to fire the bottles will put the wire in jeopardy, the MTs only have to indicate that they want us to fire on the fly and we will comply. This compromise seems a better choice than always firing on fly at the top of the cast or having to fire on the fly without notification.

 

We are now almost back at 170°E about to head out on a long unbroken series stations to the 150°W line. More on that next time,

Alison Macdonald (Chief Scientist)

Ellen Briggs (Co-chief Scientist)