The N, O, R, and S class boats (and earlier) were pretty poor boats. Accidents, mechanical failures, sinkings with aboard lost. The V-boats were a little better, but were actually onesy-twosy-threesy experiments with several basic concepts. Some were too small (V1-3), some were too large (V4-6), and some were close (V7, V8, and Cuttlefish). These last set off an evolution toward the "Just Right" Gato and Balao classes that were the heart of the USN's submarine fleet in WW2. The 9 boat Sargo class was kind of in the middle of that evolutionary succession, and except for Sealion, sunk in Manila harbor in December, 1942, all served in WW2.
I won't spoil the story for you, but brief histories of Sculpin (SS-191) and Squalus (SS-192) can be found here,
http://www.hazegray.org/danfs/submar/