[2019] Something something fat American ...

The USS Iowa fits perfectly.
2 amazing pieces of engineering, the Panama Canal and the USS Iowa.

Does anyone know of any other USN current fleet that is too wide for the canal?

@Beausabre, the third locks would likely not have been ready well into the '50s. After the war, there was not likely that there would be any major benefits to enlarging/adding to the canal zone at the time. I did find an article that spoke specifically of enlarging the Panama Canal for US BB's. http://www.czimages.com/CZMemories/thirdlocks/tcindex.htm

Other than the next step in post WW 2 CV's, what else would they have that was that large?