It must be pointed out that although the claims for damage by the PT boats in the Philippines were honestly made, they were incorrect, but not for want of trying. Rear Adm. S. E. Morison's semi-official naval history, Vol. III, "The Rising Sun in the Pacific," p. 201 notes the PTs destroyed three Japanese troop barges on one occasion, but adds: "The PT's did not accomplish much else in this campaign and on every occasion claimed more damage than subsequent investigation substantiates. Of the two cruisers and two large merchant ships that they claimed, none were actually sunk or even damaged." On p. 203 he calls White's account of the evacuation of Douglas MacArthur "overdramatic."

In my mind that's a fair description of "They were Expendable," which, after all, is a wartime movie made for a country still at war. It's up to history to separate fact from fiction.