Dear Mr. Bush,
Thank you for posting your request on History Hub!
We suggest that you begin your research by requesting his Official Military Personnel File. We searched the National Archives Catalog and located Official Military Personnel Files, 1885 - 1998 in the Records of the Bureau of Naval Personnel (Record Group 24) that includes the file Bush Elmer Eugene -- [Service Number] 001143189, [Date of Enlistment] 07/13/1918.
OMPFs and medical records of enlisted men of the U.S. Navy who were separated from the service after 1885 and prior to 1958 are located at NARA's National Personnel Records Center (NPRC), (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. If there is any information requested by the form which you do not know or which is not applicable, such as his social security number or his date of separation, you may leave it blank. Under “CHECK THE ITEM(S) YOU ARE REQUESTING” check “Other” and write that you want his entire fire. Under “Purpose” check “Genealogy.” You may also print out and attach the Catalog listing for his service record we linked above and enclose it with your order, as this contains information which will help NPRC staff locate the file. To print, click on the printer icon near the top right next to “export” and under “register” to print. For more information see Official Military Personnel Files (OMPF), Archival Records Requests.
Due to the COVID-19 pandemic, the NPRC was closed from March 23 through June 23, 2020. As of June 24, the NPRC entered into Phase One of a gradual reopening process. The center is currently only servicing emergency requests associated with medical treatments, burials, homeless veterans, VA Home loan guarantees, and employment opportunities. You may still mail the request now, but please note that it will take quite some time until NPRC can respond.
For more information about researching World War 1 era sailors, you may wish to watch the National Archives video 2019 Virtual Genealogy Fair Session 4: World War I Naval and Marine Corps Records presented by Subject Matter Expert Nathaniel Patch.
We hope this is helpful. Best of luck with your family research!