Measurements from 57 current meters suspended from anchored buoys in a network between 1.5°N and 1.5°S and from 27.5°W to 35°W in the Atlantic Ocean between February and April 1963 show speeds up to 70 cm/sec within the Equatorial Undercurrent. The bottom of the Undercurrent appears to be no deeper than 150 m; below th is dep th there is a westward-flowing current with speeds up to 25 cm/sec.
Stalcup, M. C., and W. G. Metcalf. 1966. "Direct measurements of the Atlantic Equatorial Undercurrent." Journal of Marine Research 24, (1). https://elischolar.library.yale.edu/journal_of_marine_research/1063