Over-the-Side Operations
Antarctica 2001 - Day 33
By Sharon Rippey 315-859-4672
Contact: David Tewksbury
January 7, 2002
1/6/02 1530 hrs.
64 02 S
55 13 W
+2 C, 15 knot winds, wind chill -11 C
Cloudy, slight rolling seas
Currently in the Erebus and Terror Gulf doing additional mapping of the sea floor topography before heading towards Seymour Island later tonight.
The final sampling station and over the side operations were completed in the early hours of Saturday. Collection of a 60 foot Jumbo Piston Core with full recovery and a 2 hour SCUD video run over a large sediment accumulation area in the gulf completed the sampling work on NBP01-07. During the past 5 weeks 50 sampling stations were established and along with the large number of sediment samples collected, hundreds of megabytes of digital data were recorded.
(Click image for larger version.) Photo caption: Marine techs Matt Burke and Toby Koffman stabilize the SCUD video system as it comes back on board following it's sixth successful deployment on this cruise. Yellow floats provide buoyancy. Video camera, lights and lasers are mounted just behind the "mouth" and look straight down.
The SCUD video system is a one of a kind device. Towed behind the ship on a line that is weighted down by a railroad car wheel the SCUD camera system floats around 7-10 meters off the bottom. A Hi8 video camera looks straight down at the bottom which is illuminated by 2 battery powered motorcycle headlights. A pair of lasers mounted 10 cm apart on the body provide two red spots in the picture area for scale. Mounted on the tow cable is an acoustic pinger that provides a trace of itself and the bottom on a chart recorder. Flying the SCUD is a multi-person operation. A winch operator controls the cable in and out which governs the height of the system off the bottom. Another person watches the chart recorder, reporting the distance between the pinger and the bottom at regular intervals. Two other people radio between the chart recorder's location and the winch room which are in separate parts of the ship. General trends of the bottom are easy to follow but sudden changes in bottom topography really works up a sweat on the team. Although the camera system itself is 7-10 meters above the bottom, the railroad wheel is only 3-5. Like a space craft landing on a distant planet, the system 600 meters below the surface is crossing terrain that has far more complex topography than the sensors on the ship can resolve.
The ship moves at 1.5 knots during these operations and the tape lasts 2 hours. It seems a whole lot longer for the people responsible for keeping the camera off the sea floor.
Once the system is brought back on board the housing is dried, damage is inspected (and marveled at), the tape is removed and a quick airing with a second camera, hooked up to a TV in a lab just off the deck, begins. "Oohs" and "ahs" at the passing topography, color and marine life along with caustic comments when the separation between the camera and the sea floor drops below the minimum let us know how successful the past few hours have been. This system provides us with another view of the processes occurring deep below the ocean surface.
I have been unable to work out a way to post some of the footage to the Web site while we are at sea. Once I get back at Hamilton we'll try getting some footage up on the site.
Cheers,
Dave
Top photo caption: Moonset behind a volcanic ridge on James Ross Island as we move northeast up Admiralty Sound towards Erebus & Terror Gulf.
(Click image for larger version.)
Photo caption: The fruits of our labors. In the walk in cold room Jumbo Piston Core liners each of which contain 10 feet of sediment fill most of the space. Additional cores standing upright along the walls, and boxes full of smaller samples all await transfer to refrigerated storage in Punta Arenas and then refrigerated transport back to the U.S.
(Click image for larger version.) Photo caption: Marine Science Tech, Erin Fisher helps carry in the last of the Jumbo Piston Core liners from the final JPC done on the cruise.
