The haircut Michael Madsen has is not Naval Regulation. No US Navy admiral would have long scruffy hair while aboard a ship he is in charge of at the time.
Exterior ship scenes were filmed on the SS Lane Victory, a WWII era ship & nautical museum, docked in San Pedro, CA.
The film was released on August 13th, 2018 to capitalize on 'The Meg', which was released on August 10th, 2018.
Caroline Harris's character, Commander Lynch, wears the rank insignia of a navy lieutenant.