Captain Ahab justifies his abandoning of the cruise ship survivors by describing the mayhem which Moby Dick would cause in Pearl Harbor. Pearl Harbor has a depth of at most forty-five feet. There is simply not enough water for Moby Dick to enter the harbor. Any Pacific Fleet ship commander would be well aware of this, since the relatively shallow depth of the harbor limits the speed of any ship therein.
Even the most powerful machine guns or machine cannons cannot fire projectiles which will penetrate water for more than a few feet. For the Pequod's hull to be hit by such bullets, the boat would have had to be at a depth which would have the submarine's sail out of the water.
No U.S. Navy ship commander has the authority to use a nuclear weapon without permission from the command authority of the United States. This restriction is deeply ingrained in the U.S. military, and would without question result in the officers of the ship turning on the captain at any attempt to use such a weapon on his own authority.
It is suggested that the Pequod should have shot the Osprey down with a Tomahawk, not a SubRoc. Neither the Tomahawk (a cruise missile) nor the SubRoc (an antisubmarine rocket/torpedo) is capable of engaging aircraft, as any U.S. Navy officer would know.
It is stated that Captain Ahab performed modifications on his submarine. Changes to ships of the U.S. Navy required extensive documentation and approval by the Naval Sea Systems Command (NAVSEA). No individual ship's captain has the authority to make the changes described.
The commander of a U.S. Navy ship does not have the authority to suspend the rule of Habeas Corpus (the "Suspension Clause of the US Constitution). To take the action shown without orders from higher authority would be a severe violation of the Uniform Code of Military Justice (UCMJ). The executive officer of the submarine would have been well aware of this.
At the opening scene, the captain of the sub tells his crew that they are about to enter soviet waters. But the location information on the screen just before he says this, states that they are already 50 miles inside soviet waters.
The goof items below may give away important plot points.
Captain Ahab orders his sub to chase the whale toward an atoll that is near Hawaii. There are no atolls anywhere near Hawaii. Atolls are created by coral reefs in shallow water. The water depth around Hawaii drops rapidly from the island's shores to several thousand feet under the water. The nearest atoll to Hawaii is several thousand miles away.
Atolls are created by coral reefs. Erosion of the coral produces fine sand on the shores of the atolls. But the 'atoll' Ahab chases the whale into has a very rocky shore, with no sand to be seen anywhere.
When Moby Dick enters the harbor, a crewman states that it is only twelve feet deep. As Moby Dick's body is obviously far more than twelve feet in diameter, the whale would have been beached in such shallow water.
The nuclear torpedoes fired by the sub are apparently so powerful that they completely blow up the entire island. But the blast somehow misses Dr. Michelle Herman. As a rescue helicopter finds her floating in the ocean after the blast.