Dear Ms. Demetrios,
Thank you for posting your request on History Hub!
The Merchant Marine Personnel and Licensing Records dated before 1968 in the Records of the U.S. Coast Guard (Record Group 26) are in the custody of the National Archives at St. Louis (RL-SL). Please contact RL-SL via email at firstname.lastname@example.org. Include the name (to include any variant names he may have used), date of birth, dates of service, "Z" number, and date of death, if known, in your email. If you do not know all of these things you may still submit your request, however the more information you provide, the easier it will be to locate the correct file.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RL-SL. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your research!