Only Sea Lion, Seawolf, and Sturgeon survived the war from the twelve prewar S-class boats discussed here. The losses are introduced through a contemporary-style roll call that emphasizes how rapidly the original force was reduced. The video then separates the four first-group boats from eight second-group boats and the much larger wartime third group. That chronology follows the substantial design changes made during the class's long production history.
Chapter · 12:10-14:47
Three S-class groups and the prewar boats' heavy losses
A roll call of the original boats leads into the class's three construction groups and the unusually small number of prewar survivors.