An entertaining film suffers from 2 misleading criticisms

Rating: Null/10 (7 July 2011)

We've all seen odd criticisms, like the viewer who complained that "Saving Private Ryan"--a war movie-- was too violent. Someone objected to most Star Trek films on the irrelevant grounds that practical interstellar travel may well be impossible for many reasons. Overall ratings for U-571 at some online sites suffer from the same sort of misplaced criticism.
FIRST OBSERVATION: The film's aim was entertainment--never realism. If you want the latter, see "Das Boat" and--best of all--"Downfall." You can equal criticize the Die Hard and Dirty Harry series as "unrealistic" (true) and you would be making the same mistake . Like those films, U-571 succeeds at its sole intent: action/entertainment. That is the sole ground on which it should be rated.
SECOND OBSERVATION: Repeatedly at some sites U-571 has been accused of "lying" by "crediting" the Americans--rather than the Brits--with capturing the enigma machine. Not so. The film used the American setting primarily because it was aimed at an American audience not because they wanted to steal credit from the British navy. How do I know? See the information filmmakers clearly provide at the end of the film.
Did the Brits rely on fake duplicates of German subs to capture an enigma machine? Maybe but I suspect not. Should such a plot device up counted against the film then? Not if inserted for entertainment value only. Your only question in that case should be, "Did it work?" I'd say yes.