This data set was acquired with a ship-based Gravimeter, Echosounder Sonar, and Magnetometer during Eltanin expedition ELT41 conducted in 1969 (Chief Scientist: Dr. Frank E. Snodgrass). These data files are of MGD77 format and include Singlebeam Bathymetry, Magnetic Field, and Gravity Field data and were processed after data collection.