Peter
While I agree with the premise that the time to fabricate a psub does not scale with displacement and that a diesel-electric arrangement adds a great deal of range to a boat, my hypotheses is that the optimum boat size is inversely proportional to the distance to your playground. I live is the middle of Texas far removed from any decent dive spots, as such the R300 is small and designed to be transported by trailer or by cargo container. In the debate on pure electric vs. diesel-electric, I vote for Adm. H. Rickover's and a little help from the Japanese to miniaturize the reactor to fit the R300 or Sgt. Peppers. Why shouldn't Moore's Law apply to nuclear reactors in psubs, i.e., "The size of a nuclear reactor that can be inexpensively placed in a psub should be decreasing exponentially, dropping in half approximately every two
years". Mentioning nuclear rector and psub in the same sentence will probably generate a visit from the FBI!
Great works are performed not by strength but by perseverance.
Samuel Johnson
Cliff