Dear Mr. Bitter,
Thank you for posting your request on History Hub!
The record series Seized Vessel Case Files, 1926-1935 is in the custody of the National Archives in Washington, DC - Textual Reference (RDT1). RDT1 has a folder list for the series. To request a copy of the listing, please contact RDT1 via email at firstname.lastname@example.org.
We hope this information is helpful. Best of luck with your research!