We arrived at our dive site early this
morning after an all night steam north into a brisk headwind. The first
task of the morning was to launch the benthic elevator. The elevator was
lowered off the stern of the R/V
Western Flyer using the hydrowire. It was released acoustically
at about 1,000 meters water depth and allowed to fall downward to the
seafloor, which is about 1,400 meters at this site. Much to the relief of
the pilots and scientists, the ROV
Tiburon passed its pre-dive checkout with flying colors and was
in the water before 8:00 a.m.
Today’s mission was to run a coring transect up the eastern slope of the basin we explored during the previous leg. Six stations were planned, and at each one we were to collect one vibracore, three push cores, and a heat flow probe measurement. All went according to plan until we reached station #2. The manipulator arm spontaneously went through an unexplained contortion and was subsequently unusable. We aborted the dive and recovered the vehicle with the plan to swap manipulator arms. The ROV pit crew swapped arms in record time (below), and we were back in the water in less than an hour.
Upon arriving at our next sampling
location, we proceeded with the routine of heat flow probe measurement,
then sediment coring. We loaded two more of the long vibracore samples
into the elevator and sent it to the surface, so we would have time to
recover it before sunset.
The new manipulator was working quite well
for the pilots, and we had placed a new aluminum tube in the vibracorer to
collect another sediment sample. The core easily traveled ~30 centimeters
into the soft substrate before stopping, and we continued to vibrate the
core into the seafloor. Then another equipment failure occurred. After
several minutes of vibrating the core, we were all surprised to see the
lifting winch and spool fall from the vibracorer
frame! Several minutes of discussion followed as we decided how to
recover the partially completed core without damaging either the vehicle
or manipulator, as it would be nearly impossible to recover the Tiburon
with a half-meter section of the core extending below the toolsled. A
series of deft moves by our resourceful pilots enabled us to extract the
aluminum core from the frame. The vibracorer was unusable, so the decision
was made to abort the dive and recover the vehicle. Despite this second
major hardware failure of the day, our dives today were successful because
we completed our primary goals for five out of six stations.
Pete Zerr and Paul Ban spent some time this afternoon towing the benthic elevator back towards the Western Flyer once they found it floating at the surface. It had drifted away from the ship as it rose up through the water, and the ship had moved in the opposite direction. All the vibracores survived the transit and soon the science lab was a blur of activity. These cores and the smaller push cores kept the science party busy until past midnight, while the ROV pilots prepared Tiburon for tomorrow’s mission.
“It was the best of times, it was the
worst of times. It was the ocean of light, and we dove into the darkness.
It was the push cores of hope, it was the manipulator of despair.”
Cheers to all friends and family back
home—we miss you!
As promised in
last night’s update, we will reveal the identity of those who posed for
the steel-toe trivia photo. From left to
right: Peter Walz, Steve Hallam, Pinkie, Bill Ussler, Patrick Mitts, and
crew drummed up another mystery photo for those of you with inquiring
minds. Any guesses as to what this is and who is holding it? The answer
will appear tomorrow.