Dear Mr. Lukesch,
Thank you for posting your question on History Hub!
We searched the National Archives Online Catalog and located 15 files unite & 6 items relating to “Danube barge.” Also, we located 6 series, 240 file units & 13 items pertaining to “Straubing.” For access to these records, please contact the NARA unit listed in each description.
In addition, we suggest searching fold3.com for any records on “Danube barges” and “Straubing” as many of the National Archives records have been digitized by them and made available online.
Since the 393rd Infantry Regiment captured Straubing on 27 April 1945, we searched the World War II Operations Reports, 1940-1948 in the Records of the Adjutant General's Office, 1905-1981 (Record Group 407) and located Histories for 15 November 1942 - June 1945; After Action Reports for November 1944 - 10 May 1945; S2/3 Journals and Supporting papers for November 1944 - 11 August 1945; Lessons Learned in Combat for 3 January - 3 May 1945; and G-3 Periodic Reports for November 1944 - June 1945 of the 393rd Infantry Regiment, 99th Infantry Division. For access to these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We hope this is helpful. Best of luck with your research!