Since we have to start somewhere, this morning is as good a place as anywhere. At sunrise we found ourselves wrapping up the collection of our sonar data sandwiched between Pinta and Marchena Islands. After nearly two weeks of collecting data, we took the MR1 (side-scan sonar device) out of the water. Krista and Will watch anxiously as the MR1 is brought back in.
Reeling the several million dollar piece of equipment back to the ship is a bit of a stressful task as it is, which was not helped when we found out (just as the fish reached the surface) that there was a problem with the weight that held the machine’s front end down so that it wouldn’t smash into the ship at arrival.The hook that attaches the weight properly was broken, making it hard to retrieve the fish.
After some serious deliberation and a joint decision made by the ship crew and the science party, a spare steel beam was found that could be used as a proxy for the faulty weight. Though there were a couple hair-raising moments, the beam did the trick, and the MR1 was successfully recovered to the relief of all those on board.After many trials, the MR1 is finally coming back on board!
Reeling in the MR1 “fish” signaled that dredging would finally begin, and our first dredge got underway this afternoon and has been memorable to say the least. Just north of Pinta Island, we aimed to dredge what appeared to be (from bathymetric maps) the farthest extent of a lava flow from Pinta. We may or may not have mentioned this before, but the winds in the region come primarily from the south. Since the ship only moves at about ¼ knot during dredging, we figured it would be a good idea to be facing into the wind as much as possible to avoid being blown off track. As we’re dredging from the ship’s starboard-side A-frame winch system, we had planned our dredges to comb the seafloor from west to east so the ship to stay pointing south. Unfortunately, strong currents in the area (possibly the result of being in such close proximity to Pinta Island) initially caused some headaches by pushing the ship off course and threatening to pull the dredge wire underneath the hull, which would not be good for the ship or the dredge wire. After some finagling, a safe course was set and the dredge continued smoothly.
To make sure that the dredge was receiving “bites” on the seafloor, we monitored the tension of the dredge wire. A steady increase in the wire’s tension from, say 1,000 lbs to 2,200 lbs indicates that the dredge has caught onto something – preferably intact basalt – signaling the beginning of a bite. When the wire tension rapidly decreases from 2,200lbs to, say 800lbs, it hopefully indicates that whatever has caught the dredge has broken off, leaving us with several bits of good sample rocks to work with. While monitoring the tension this afternoon we definitely recorded a few bites, though nothing seemed particularly out of the ordinary. Will, Drew, and Ally secure tag lines to the dredge so it stays steady when it is brought up.
We hadn’t realized yet that we had snagged an extremely impressive rock sample, which had both the first-timers as well as the seasoned dredgers in a state of giddy excitement. A giant piece of intact pillow (“toothpaste”) lava that was too large to fit inside the dredge bag, the rock was caught precariously on the chain just above it.
Thanks to the deft maneuvering of Drew – one of the Res Techs, Denny, Dan, and the winch and crane operators, the rock was recovered and set aside (by crane) on the deck where it gathered a large crowd (pictures below).
Drew, Denny, and Dan securing the huge rock to a crane in order to move it.
Cheif scientist, Karen Harpp, and her prize catch!
Angela and Ally show off their muddy hands after sifting through piles of sediment brought up by the dredge.
It was an exhausting and exhilarating first day of dredging, and we’re hoping that the excitement of the first dredge continues through the next 39.