Alternate Leg ID: 81-G-12
Area of Operations: Oceanographer Canyon, Lydonia Canyon, Atlantis Canyon, Alvin Canyon, Georges Bank area, United States, North America, North Atlantic
Dates: July 27, 1981 to August 17, 1981
Objectives: Conduct high-resolution mid-range sidescan sonar and single-channel seismic profile surveys of the continental slope around Atlantis to Alvin and Lydonia to Oceanographer Submarine Canyons near lease-sale blocks.
Type of Activity:
Information to be derived:
Summary: The electric motor for the winch caught fire on July 28th after 7 hours of use. Nearly 1,400 m of cable and gear were over the side at the time. Dave Twichell on M/V WHITEFOOT was conducting a survey not far from the GYRE; the WHITEFOOT rendezvoused with GYRE on the night of July 28 to provide us with spare blocks and hawser to facilitate recovery of the cable. We thereupon spent 38 hours hauling in the cable by means of a deck capstan, mooring hawser, and two blocks. The cable was brought in 3 m per pull and hand spooled on the cable drum. On July 31st R/V GYRE returned to Woods Hole to have the electric motor rebuilt. On August 3rd, the survey resumed along the slope in the Atlantis-Alvin Canyons area. About 100 km of image data were collected before a hydraulic pump on the winch failed. On August 5th the gear was brought on board by the marginally operable winch. R/V GYRE returned to Woods Hole on August 6th for emergency pump repair. By August 8th it was clear to us that no repair could be counted on in the foreseeable future. The majority of the Lamont crew returned to shore and USGS personnel came aboard to help conduct a seismic survey. An excellent seismic survey was completed in 4.7 days using airgun, sparker, and 3.5 kHz profiles at 2 km line spacing. In the remaining 3 days of the survey, an excellent sonar survey of the slope between and adjacent to Atlantic and Alvin Canyons was completed. Sidescan sonar data: 375 km; Seismic profile and 3.5 kHz data: 1,230 km.
USGS Project Number: 9840-51823 9840-52806
Contact: Dennis O'Leary ()
Map for Area of Operations :