But, I used a Duck, Duck, Go search engine and it pointed me directly to the list of BGP's at NARA.
... https://www.archives.gov/research/cartographic/ship-plans ...
Says they have 3149 BGPs at NARA. From my experience, the more modern BGP's (I pulled some SHERMAN Class destroyer BGPs) are smaller than WWII era plans so they fold-up and take up less space. Makes them harder to read the blueprint copies. I never pulled any DLG/CG's.
... https://catalog.archives.gov/search?q=*:*&f.ancestorNaIds=147967594&sort=naIdSort%20asc ....
Here is a list of BGPs of DLG's available;
... https://catalog.archives.gov/search?q=*:*&f.ancestorNaIds=147967594&sort=naIdSort%20asc&offset=1780 ... (pg 90 and continued on pg 91)
I don't know which units you are interested in.
How many are available online is uncertain to me. Because when I tried the "Available Online" link, only three ships showed up and I know there are MORE than that available. But you can go up to the SEARCH BOX and type in "Drawings for USS (specific ship name)"