Dear Mr. Sullivan,
Thank you for posting your request on History Hub!
If you are searching for Merchant Marine records prior to 1968, the Merchant Marine Personnel and Licensing Records 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, date of birth, dates of service, "Z" number, and date of death, if known, in your request.
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.
To request Merchant Marine personnel service jackets for 1968 to the present, please write to the USCG-National Maritime Center (NMC-421), ATTN: Correspondence Section, 100 Forbes Drive, Martinsburg, WV 25404. Please include name, date of birth, copy of death certificate if deceased, Social Security number, address, and Z or Service number. Their website is https://www.dco.uscg.mil/national_maritime_center/.
We hope this information is helpful. Best of luck with your research!