The Seabed Worker departed the Zone 2 search area for Praia, Cape Verde Islands at about 24/1930z and at 25/0635 was at 5°31'36''N 29°20'32''W Hdg 028.6°T Spd 13.0 knots.
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originally posted by HN39 ...
In other words, the tapes obtained in the mediterranean were dated before July 1st.
I think you may have misinterpreted what was going on. The Navy conducted tests using another Rubic class submarine to optimise the sensitivity of the sonar receiver to 37.5kHz. I seem to remember reading that the SNA fleets sonars operated at a nominal 18kHz, and following the adjustment, the mod details were relayed to the Emeraude, which from 01 July to 10 July operated in the optimised mode.
The Thales re-examination of the tapes recorded by the Emeraude used other techniques to extract 37.5kHz data hidden in the background noise.
mm43