Continuity mistake: When Tyler is out on the deck, he has his hand raised. When the "boat secure" order is shouted it's now lowered and holding on to his glass. (00:12:10)
Continuity mistake: After the German captain has attacked Tank and handcuffed him to the crane, the pattern of blood on Tank's face changes at least twice. First, he has two channels of blood running down the left side of his face under his nose and on his chin, and no blood on his lips or the right side of his face. Then, when Eddie and Tyler arrive, there is blood smeared all over Tank's nose and lips. Finally, after Tyler takes the cuff off and is yelling at Tank, all of a sudden there is a line of blood from Tank's nose across his cheek to his right ear. (01:09:05)
Continuity mistake: Just after Mazzola's been killed, Tyler unlocks the handcuffs from Tank. The handcuff starts swinging as soon as Tank pulls his hand free, but in the next shot it's stopped moving. (01:09:42)
Continuity mistake: Mazzola has just been killed and when Tyler helps Tank, first he holds Tank using his left hand, then the next shot by his right.
Answer: The scars you see on Tank's face are fake, pure makeup. They wanted the character to have a gritty look.