Seeking isometric charts of USS Helena decks

Dear Mr. Schuh,

Thank you for posting your request on History Hub!

It is possible that isometric charts are stored with the ship’s plan. Ship Engineering Drawings, ca. 1940 - ca. 1966 in the Records of the Bureau of Ships, 1940 - 1966 (Record Group 19) are in the custody of the National Archives at College Park - Catographic (RDSC). Please contact RDSC via email at carto@nara.gov for a search of these records.

We hope this information is helpful. Best of luck with your research!