2010/05/16
Labels: showcomments, folger, pinnacle, bpr, tully, ropos
On 15 May 2010, we made two dives in Folger Passage, once to Folger Deep and a second dive to Folger Pinnacle. Our goals were to:
- swap out the Folger Bottom Pressure Recorder (BPR)
- find and mark the end of the cable extending from the node up to Folger Pinnacle
- clean up our little mess from last year
Happily, our efforts met with success on all three counts!
BPR Swap
The Folger BPR, which was deployed last September, has recently ceased operating properly with what we suspect may be a malfunction of the pressure sensor. To remedy this situation, we replaced it with a brand-spanking-new one. The following photo set shows the two BPRs in side-by-side comparison.
Tying onto a Loose End
Many are eagerly awaiting the installation (sometime this year) of an exciting new platform at Folger Pinnacle. Unlike our other installations, this custom-designed platform will be deployed by scuba divers working in the shallow (~22m) waters of Folger Pinnacle. Learn more about research planned for this location
.
In preparation for the Folger Pinnacle installation, we laid a cable last September, extending from the Folger Passage node up to a rocky crevice close to the future study site. In the ensuing months, however, dive crews have been unable to locate the cable end. We weren't sure if the cable had been buried by sediment, swept away by storms or perhaps eaten by sea monsters. So ROPOS went back to the scene of the crime, tracing the cable from the node up into the shallows of Folger Pinnacle. To our great relief, we easily located the cable end. And this time, we marked it with a couple of floats to help the scuba crew find it next time.
Cleaning up After Ourselves
During our fall 2009 installation cruise, large swell complicated work in these shallow, rocky waters. Surging waves made it nearly impossible for ROPOS to hold position, and we worried that our newly laid extension cable might be swept away by heavy surf and strong currents. In an effort to secure the extension cable, ROPOS dove carrying a tool tray loaded with burlap sandbags. The idea was to drop the sand bags on the cable in key locations, thus holding it in position until follow-up work could be done.
But our plan was undone almost as soon as we reached the seafloor. Like a pro wrestler, heavy surge lifted ROPOS then slammed it into the rocky seafloor, tool tray still attached beneath the vehicle. The tray frame snapped, forcing ROPOS to recover, carrying only the harness section of the frame. We attempted to retrieve the rest of the tool tray on the following dive, but the surge was too strong, and it was too risky to approach it. So the clean-up task was left for another day.
That day came on 15 May 2010, when calmer waters allowed ROPOS to loop a rope around the broken tool tray and haul it back to ship.
We weren't the only ones pleased with the result. Once secured to deck, the tray rapidly attracted the attention of numerous seagulls, seeking to snack on the rich variety of shellfish that had grown onto the tray over the winter.
