The realistic rendering of the Nth Atlantic and the overhead shots of the manoeuvering between adversaries already makes Greyhound stand out amongst all the other destroyer v's sub movies that have come before it. The audience is in on the action and not some neutral observer trying to figure out where the hell all these ships are going. It is evident Greyhound is well produced and directed.
Always going to be a one sided affair for a sub to take on a warship in a surface duel but the excitement adds (greatly) to the narrative and makes the movie..well, a MOVIE! Doenitz in '43 I think actually encouraged his boats to surface engage aerial attackers rather than dive for safety which was not working, and redesigned his boats with double armed winter garden's for this purpose, and a lot of anti-sub a/c and their crews were lost as a result so the truth is a lot of nazi submariners did stand and fight to the death.
Hmm... the U-Boat has a swastika painted on its conning tower which is rather comic-bookish and is really not needed but I suppose is put there for the lowest common denominator who the producers deemed needed a labeled villain, and the most villainous villains are of course the Nazi's, so there's no mistaking.
I am optimistic that Greyhound will be a success even for all its inaccuracies and flaws which I can see are there, but couldn't care less anyway. And I hope so because it will encourage other likewise movies to be produced. I'm sure the immensely successful Dunkirk (with all ITS flaws) can be given credit for setting a trend in the revival and interest in WWII movies (see also Hacksaw Ridge) if they are well produced and directed.