Last time I looked there was no place on the National Archives (NARA) web site to search for ship and submarine plans.
Here is the NARA search page:
https://www.archives.gov/research/catalogIt isn't very useful for searching for ship plans.
You can go to the "Contact Us" page and send an email request for information about a specific ship or ship class.
Archivists are not ship modelers, and they can't read you mind. There are about 17,000 ship plans in the Archives and they will not search them all to try to find what you want. So you have to be pretty specific and give as much information as you can, such as ship name, hull number, ship class, etc. Tell them you want plans, drawings or blueprints. They have always answered my questions, but expect a delay of up to six weeks before receiving an answer. You aren't the only one asking questions and there are a limited number of Archivists.
The Historic Naval Ships Association (HSNA) has a web page for finding information at the National Archives:
http://www.hnsa.org/resources/manuals-d ... s-at-nara/HSNA also has a page for searching for ship plans at NARA:
http://archive.hnsa.org/doc/nara/searchplans/index.phpPhil