Saturday, June 7, 2014

Research Cruise UPDATE: Sampling again after brief stop in Panama City to resupply... and relax

Nikki Morgan, Caroline Johansen...
The team completed Sites AC-1 and PCB-04 and the WB2 transited to Panama City for resupply and to meet with a MacArtney Inc. technician for consultation about the malfunctioning MILET cable.  Although members of the crew and science party enjoyed an evening of karaoke singing in a local club, the news about the MILET was not good. 
 
Turns out that the problem is in the armored cable that connects the cameras and instruments on the toolsled with the surface control and data collection.   The cable combines copper conductors with two fiber-optic conductors.  The copper cables provide power for the instruments, while the data and control commands are communicated via one of the fibers.  (The other fiber is meant to be a spare.) 

...and Boryoung Shin
serenading the locals
at a waterfront karaoke club
We were able to trouble shoot a major loss of data transmission at higher frequencies in the fiber we had been using, but the problems lie deep within the 3000 m cable drum.  The spare fiber, most unfortunately, is completely severed.  We don’t really understand how this problem arose, but think it might be related to progressive problems with the level wind — a system of guides that is designed to wind the cable evenly onto the drum.  This has been problematic for a long time, but it is a bit surprising that it would cause such severe problems when the cable really has not been stressed that much.  In any event, the cable is now beyond repair, with neither fiber operable, and will have to be replaced.   This means no more MILET work on this cruise.


R/V Weatherbird II at the Panama City Marina
R/V Weatherbird II got back underway at 4pm eastern on 6 June.  We made a brief stop on the way out to collect some calibration data for the USBL and then proceeded to site PCB-05 for a set of 4 multi-core lowerings.  With no possibility of doing MILET surveys, we will use that portion of the cruise schedule for an expanded piston core collection, targeting the geologic flow channels that characterize the northeast side of DeSoto Canyon.  All previously scheduled multi-cores will be attempted—our anticipated cruise track is outlined in the table below.  We expect to be back on the S-36 site in about 36h to complete the multicore series that was previously curtailed by rough weather.  


The weather is projected to be very favorable over the next 2-3 days and we anticipate many happy hours of sectioning sediment cores.  Our revised end of cruise will happen on 13 June in St. Petersburg.  Two members of the science party departed the ship in Panama City — Eric Howarth with a twisted ankle and Heather Broadbent who has a critical appointment prior to our scheduled return.

Site
Lat
Long
Depth
Plan
PCB-05
29.44167
-86.78333
397m
CTD, 4MUC
Seep A
29.043028
-87.282473
1112m
CTD, 3MUC
AC-4
29.00039
-87.507422
1720m
CTD, 3MUC
s36
28.9164
-87.6691
1871m
CTD, 3MUC
PC-8
28.687258
-87.679458

Piston Core
XC-4
28.6365
-87.8685
2308m
CTD(samples), 3MUC, Piston Core
peanut mound
28.53043
-88.070877
2111m
CTD, 3MUC, Piston Core(2) (PM-1,PM-2)
PC-9
TBD
TBD

Piston Core
PC-10
TBD
TBD

Piston Core
PC-11
TBD
TBD

Piston Core
PC-12
TBD
TBD

Piston Core
PC-7
29.190257
-87.458165

Piston Core
PCB-06
29.195
-87.438333
1145m
Piston Core
16b Huettel site
29.55417
-87.21272
200m
1MUC
St Petersburg FL
27.762697
27.762697

Home J

Posted by:

Ian MacDonald
Florida State University


1 comment:

  1. Ian. Sorry about the struggling with the winch. I hope Mcarty fix that soon.
    How is the PC going?. You should rig it with a chain so you can deploy it with Mauricio attached to it. That wat he can get a better taste of the mud...
    Glad to hear you will have good weather will be good.
    Hang in there boss.
    Oscar

    ReplyDelete