The acoustic transit times for a float to sink to a bottom-anchored triangular array of disposable transponders are used to construct a horizontal current profile in the anticyclonic shear region of the Gulf Stream, southeast of Cape Lookout, North Carolina....
Pochapsky, T. E., and F. D. Malone. 1972. "A vertical profile of deep horizontal current near Cape Lookout, North Carolina." Journal of Marine Research 30, (2). https://elischolar.library.yale.edu/journal_of_marine_research/1236