Factual error: When the submarine rises in the waters of Norfolk and you see Norfolk in the background, there is one blatant problem. There are NO mountains in Norfolk. Most of Norfolk, Virginia, is below sea level.

Continuity: During the final chase scene, Captain Dodge says that it's overcast, and they surface. The first shot of the Stingray shows a hazy day. When the Orlando surfaces afterwards, it's clearly that one piece of stock footage of a Los Angeles-class submarine surfacing - not only is it sunny, but the ship shoots up from an emergency fast rise. After that, the shots of the Stingray in pursuit, and that of the torpedoes hitting the target ship, show it to be sunny rather than overcast. [It's not just stock footage of any old submarine surfacing. It is in fact the shot of the submarine in Tom Clancy's The Hunt For Red October surfacing - exactly the same footage. Some kind of in-joke, perhaps?]