Gray Lady Down is a 1978 Disaster Movie directed by David Greene and starring Charlton Heston as Paul Blanchard, captain of the nuclear-powered U.S. Navy submarine Neptune, who's on his last trip before being promoted to squadron commander.While surfaced and returning to base, the Neptune picks up another ship on its radar off in the distance, on what would be a collision course. The ship, a Swedish freighter with a number of equipment failures, has no idea that the Neptune is in their path and is quite likely violating the rules for traveling on the open sea. As the freighter gets too close, the watch officer orders that the collision alarm be sounded. The freighter operator then makes a mistake and turns the ship even more steeply into the Neptune, resulting in a collision. The submarine sinks, landing below its crush depth on a ledge near a steep trench.Captain Bennett (Stacy Keach), a rescue force commander, gets a call at home announcing that a submarine has been rammed, resulting in it sinking ("Gray Lady Down"). He calls up every resource he can get his hands on, including having a DSRV underwater rescue ship brought in, and an experimental mini sub called The Snark, whose captain, Gates (David Carradine) has his own ideas about how his boat is to be operated.The rescue force must try to save the survivors before the Neptune slips off the ledge, falling irretrievably into the trench and imploding.
- The Captain: While Gates is technically captain of the Snark, Captain Bennett is superior to him, and orders him to take one of his own men with him (instead of Gates' second in command) to do the search for the Neptune that Gates considers unqualified. After the man mistakes a sunken sonar target for the boat, Gates surfaces and begs Captain Bennett to let him use his own man. Bennett asks him if the fact that the guy made one error was sufficient reason to abandon the search, Gates says, "When I'm steered to a '52 DeSoto (instead of a submarine about a hundred times the size of an automobile), yes, sir!"
- Insert Grenade Here: A gravity slide has knocked a large boulder into the boat, and shifted the position of the Neptune's emergency escape hatch so that it can no longer be reached from the DSRV. Captain Bennett has an idea. Have the Snark bring down a shape charge of C4 in its carrying arm so that the explosive will pulverize the boulder but not damage the Neptune, allowing it to roll forward and right itself.
- Military Maverick: Captain Gates. He designed and built a specialized mini-sub that can do a lot of useful functions with nothing but scrounged resources and the help of his second in command. He's damn good at what he does, and he knows it.
- Race Against the Clock: While there's enough air and food for the crew to last until rescue, the place where the boat is resting is subject to severe gravity slides. They have perhaps 22 hours if everything holds. If anything goes wrong, the ship falls into the trench and it's a two-mile ride to the bottom. As the ship is already below its rated crush depth, any further sinking would cause it to implode, killing any survivors.
- Shout-Out: While the crew is waiting, they're watching the movie Jaws.
- Suicide Mission: Gates decided to take the Snark down alone to watch the explosion to blow up the boulder (see Insert Grenade Here) so they can know if it took. Gates refuses to let his second in command come along because of the danger. The explosion takes and the DSRV can rescue the remaining men. When a gravity slide causes the Neptune to start to slide into the trench during the rescue, Gates pushes the snark in the way, sacrificing himself to block the Neptune from sliding further, giving them the extra few seconds to escape, before the Neptune and the Snark slip and fall into the trench.
- Lost in Transmission: Part way through the rescue, the Neptune's radio fails. To signal to it what is happening, the Snark goes to the crash site, lands on the Neptune, and the Snark's captain then uses a wrench to tap Morse Code through the hull.