The O'Brien class reached production as war began, but the Navy needed more hulls than a six-ship class could provide. Each carried four 4-inch guns and eight 21-inch torpedoes without reloads. Later anti-submarine service, including participation in sinking U-58, shows that the design itself was useful. The General Board and political authorization process nevertheless produced only six. Useful service did not make six hulls sufficient.
Chapter · 42:03-43:26
O'Brien-class war service meets a six-ship limit
Four 4-inch guns, eight 21-inch torpedoes, and later action against U-58 show why the O'Brien class mattered, while the six-ship authorization repeats the larger procurement failure.