Date: Fri, 22 Nov 1996 07:07:37 +1200
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Mid-point Report of the AESOPS Sediment Trap Mooring Deployment Cruise

Weeks like this help to remind me how much human effort it takes to do
large-scale, integrated ocean science.  This is not a lead in to a
"hard times at sea" story.  Actually, things have been going very well
on the Sediment Trap Mooring Deployment Leg of the N.B. Palmer.  We got
an early start from our meeting point where helicopters landed on seven
feet of ice--Walker Smith and the rest of the Process 1 scientific
party with the help of an energetic ASA crew had already pulled vans
from the hold and packed up much of their gear by the time we arrived.
Despite distractions from a large group of emperor penguins that had
adopted the pool of open water behind the ship, this first-ever cruise
changeover on sea ice went more rapidly than expected.  Initially these
curious birds would rush to greet every helicopter load, but they soon
learned that they could stay by the water, and the helicopter beings
with cameras would come to them.  Our penguins watched us pull away on
the evening of November 11--more than 48 hours ahead of schedule.  This
accomplishment required intense work by John Albert's ASA team as well
as the scientists, and the two days saved have been critical because
the original schedule had no weather days--in fact, my estimates showed
that our time allottment of 17 days was a day and a half too short.

One week later and we have completed what we hope has been the hardest
part of the cruise.  Three of the seven total moorings that are planned
for AESOPS are done.  While that is not the half way point in numbers,
it probably is in effort.  The first three moorings, being within ice,
meant that they had to be done anchor-first instead of the usual
anchor-last mooring deployments.  Consequently, from the moment the
2000 lb anchor was lifted from the deck and the operation began, the
mooring crew was experiencing high tension both mentally and on the
mooring line.  While the tension-maintaining Lebus winch was absolutely
essential to the operation, it did not eliminate all the tricky
dimensions to the operation.

On the first Ross Sea mooring (76.5 degrees S, 178 degrees W) at the
2/3rds completion point, a link caught while passing through the winch
and the wire rope snapped in an instant.  The good news was that no one
was hurt, although the wire  lashed into the back of Larry Costello,
who says he felt nothing (another reason for wearing a well-padded
"float coat").  The bad news was that we had catastrophically deployed
a mooring with only a deep trap, a current meter, and less than optimum
flotation.  After considering our options, we decided to leave the
mooring in place (there was too much ice to risk recovery) and to dip
into our spare gear and start over--deploy a second complete mooring
with the desired two traps.  So once again the mooring crew led by
Steve Manganini of WHOI and Chris Moser of OSU began the high tension
task of deploying mooring 7.  Anyone who has been in this business very
long has experienced the heartbreak of seeing the end of a difficult
task in sight, only to have to start over.  But, this turn of events
was accepted with good spirits and even humor.  The JGOFS program has
brought together a remarkable mooring team!

On mooring 6, the northern Ross Sea mooring (73.5 S, 177 E), a new
perturbation of the hazards of anchor first mooring deployment was
revealed.  A rope connector on a take up spool broke causing a loss of
tension on the Lebus winch.  Again the mooring was headed for an
unexpectedly early launch, but Larry Costello saved the day by grabbing
the wire before it could snake through the Lebus winch--an act all
mooring initiates are taught never to do.  Because Larry is a very
experienced hand in this work and because he still has his hand,  no
one has second-guessed his quick response.   It seems, however, that
Larry has developed a nervous twitch.

The deployment of Mooring 5 (66 S, 170 W), the longest of the anchor
first moorings with more than 2000 m of wire rope, current meters, and
six large sediment traps, went very well.  Despite being embedded in
rapidly drifting ice, we were able to place the mooring within 0.3
miles of our intended target.   Some attributed the smoothness of the
operation to the small shrine with a burning candle and some incense
that had been set up on the Lebus winch.

The rest of our sampling program, although a smaller aspect of our
work, has gone very well.  Suzanne O'Hara ably runs the CTD operation
and provides us with incredible maps that remove the guesswork from our
mooring deployments.  The underway seawater system continues to have
problems in the ice, but David Chipman and Stephany Rubin observed pCO2
values above atmospheric at the first three mooring sites as expected
for ice-bound conditions.

At this point we are looking at the hand we have been dealt and seeing
the necessity of good weather and good luck in the remaining days.
With four moorings and many miles to travel before we reach NZ, we have
less than 12 hours of contingency time.  Given the experience of the
last three transits through the Polar Front, even if we play our cards
perfectly, the seas will have the last say as to whether we make it to
Lyttleton eight days from now.

Jack Dymond for the 17 other scientists from AESOPS Sediment Trap
Mooring Deployment Cruise, NBP 96-5.
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