Comments by "Steve Valley" (@stevevalley7835) on "US Navy Fleet Problems - Budget cuts and Grand Battles (XIII-XVI)" video.

@janwitts2688 the superimposed turrets, the brainchild of Joseph Strauss, during an earlier stint at BuOrd, was to address the very slow rate of fire of the larger guns. The idea was that, while the 12" or 13" on the lower level were being reloaded, the 8" on the upper level could keep up a hot fire. Then, the Navy discovered that, if they worked on the ergonomics a bit and trained the crews a bit, the rate of fire of the larger guns could be improved dramatically, rendering the upper level guns redundant.
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