Plot hole: After the marines fire into the crowd and things die down, Jackson tells his men to stay down because of possible snipers. Yet he is standing upright the whole time. Not the best tactical move. One sniper and the mission loses its commanding officer.
Plot hole: At the beginning of the movie, the German commander sends a radio transmission with the damaged sub's position at "AL 85-32." The German Kriegsmarine divided up the Atlantic in grid squares like these, but "AL 85-32" means the damaged sub is just roughly 375 miles west of Ireland, but more than 2700 miles from the US east coast. There is no way on earth the Americans beat the Germans to this location, especially since the German supply sub is already en route. Funny enough considering the controversy about the movie, for this position the British would have been in perfect position to intercept.