Trivia: U-571 cause quite a stir in England especially in the small northern town of Horsforth (where I actually live), because we felt the movie 'Hollywood-ised' a British victory. The people of Horsforth raised an astonishing £241,000 in one week (about £4million today) to fund the building of the HMS Aubretia, the ship that captured the first enigma machine when it depth charged U-110. It caused so much upset amongst people that President Bill Clinton wrote a letter to the people of Horsforth praising the town for their part in the war effort. The letter is now on display in the local museum.
Trivia: Matthew McConaughey didn't like his character's background, so he asked that it be changed from the original, not being promoted because he was a drunk, to basically never making a decision that might cost someone their life.
Answer: The scars you see on Tank's face are fake, pure makeup. They wanted the character to have a gritty look.