Monday, June 10, 2013

Miracle workers of the Langseth overcome the curse of the Costa da Morte

After days of uneventful and productive data acquisition, a pall fell over the R/V Langseth. Early Sunday morning, one of the streamers began to report communication errors and soon failed to communicate at all.  A series of tests over the ensuing hours revealed that the problem was not on the ship but in the equipment out in the water.  Recovering and repairing seismic gear is not a quick task. To access this streamer, we had to undo many of the steps required to put it out to begin with: recover the port paravane, shift Streamer 3 starboard and out of the way, and then reel in part of Streamer 4. After hours of troubleshooting, the technical staff of the Langseth brought Streamer 4 back to life.  All of the equipment on the Langseth is… not new, and this certainly applies to the seismic streamers. The technical staff on the ship are pros at keeping this equipment alive (and many cases bringing it back from the dead). Twelve hours after the problems with Streamer 4 began, it was back in the water, and we were ready to start collecting data again. 
But no sooner had one problem been solved, another appeared. This time the trouble arose from the failure of a piece of equipment on the ship that is at the heart of our acquisition system – the real time navigation unit (or RTNU, for those in the know). This component gathers satellite and other navigational information from the seismic equipment and delivers it to the navigation software on the ship so that we can determine the positions of all of our equipment in the water, and where and when we need to be shooting.  Once again, the dedicated technical staff of the Langseth came to the rescue.  Painstaking checking and double-checking of each component in the RTNU began last night and continued into the early hours of the morning. In the wee hours, it’s easy to get a little superstitious.  Did all these problems arise because Tim Reston and I each accidentally drew in lines on our chart indicating that we’d completed lines in our 3D box before we actually had? Or was it the curse of Costa da Morte (Coast of Death)? This part of the Galician coast is known for its shipwrecks and nicknamed accordingly. Of course, the real culprit was the non-newness of the gear in question. Once again, the Langseth’s miracle workers saved the day by assembling the working parts of various old RTNU’s into one working unit.  Thanks to their efforts, we are up and running again….

RTNU carnage on a table in the main lab.

Donna Shillington
10th June