The USS Andersonville is marked as the CVN 68 which is the real life USS Nimitz.
When the bomb goes off, Decker warns the Captain to prepare for an EMP (Electromagnetic Pulse). A nuclear weapon that goes off underwater does not generate an EMP.
When the helicopter flies over the ship which is called the Intrepid, at one point the camera hovers beside it revealing the true name of that ship: Pacific Princess.