Dear Mr. Jones,
Thank you for posting your request on History Hub!
We suggest that you request a copy of his Official Military Personnel File (OMPF). OMPFs and medical records of officers and enlisted personnel of the U.S. Marine Corps who were separated from service after 1958 and prior to May 1994 are located at NARA's National Personnel Records Center (NRPC), (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. To request these records, please mail a completed GSA Standard Form 180 to NPRC. Certain information in the records is not available to the general public without the written consent of the veteran or his next of kin. For more information see Request Military Service Records.
However, due to the coronavirus public health emergency, National Archives research rooms and museums are closed to the public until further notice and the National Personnel Records Center is servicing only urgent requests related to homeless veterans, medical emergencies, and funerals which may be faxed to 314-801-0764. We thank you for your patience and look forward to resuming normal operations when the public health emergency has ended.
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 logs of the USS Chicago (CG-11) for 1966. These deck logs have been digitized and can be viewed online through the Catalog. Please note that the Catalog does not always list logs in chronological order. While deck logs do not always give information about each individual crew member, they can provide insight into the activities of the ship as a whole.
We also searched the Naval History and Heritage Command’s (NHHC) Dictionary of Naval Fighting Ships and located an article about the USS Chicago that includes a few paragraphs about its 1966 Vietnam deployment. Command Operations Reports for that time period are in NHHC custody. To request reports from a specific ship and year, contact NHHC via email at email@example.com.
We hope this information is helpful. Best of luck with your family research!
There are many secondary resources available here that many people use. Do you happen to have your relatives name.
However you can also request his Military records from the NPRC in St. Louis. When doing so use the SF-180 and use the box marked "other" and select "genenology".
I would suggest waiting until normal business operations resume. Currently they are only processing emergency requests.