Dear Mr. Taylor,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the Logbooks of U.S. Navy Ships and Stations, 1941 - 1983 in the Records of the Bureau of Naval Personnel (Record Group 24) that include the deck log of the USS Sarsfield for 31 July 1968. The log states that on that day the Sarsfield was on passage from Luanda, Angolga, to Lourenço Marques (now called Maputo), Mozambique. The deck log gives the location of the ship at 0800, 1200, and 2000. The locations are as follows:
Longitude 30-35.2 South
Latitude 30-39.3 East
Longitude 30-01.7 South
Latitude 31-13.2 East
Longitude 28-20.8 South
Latitude 32-37 East
For access to these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We hope this information is helpful.