Tom Clancy, who died yesterday at age 66, was renowned for the technical detail of his best-selling military thrillers. This attention to detail was present in his first published novel, The Hunt for Red October, which centers on the attempt to defect by a Soviet submarine commander named Marko Alexandrovich Ramius. (Ramius pilots an experimental nuclear submarine called the Red October.) Clancy’s book was the first work of fiction published by the Naval Institute Press, an imprint of the U.S. Naval Institute. Clancy had a relationship with the press because he had written articles for their magazine, Proceedings of the U.S. Naval Institute.
Given those origins, perhaps it’s unsurprising that the book includes remarkably fine-grained technological details about submarines. At one point in the book we learn that the Red October uses “a highly sensitive device called a gradiometer, essentially two large lead weights separated by a space of one hundred yards. A laser-computer system measured the space between the weights down to a fraction of an angstrom. Distortion of that distance or lateral movement of the weights indicated variations in the local gravitational field,” the book explains. “With careful use of gravitometers in the ship’s inertial navigation system,” Ramius “could plot the vessel’s location to within a hundred meters.”
In fact, “no Soviet vessel actually carried such elaborate gear.” But something like it was in use by the U.S. Navy. “In the 1970s, driven by both navigation and missile launching requirements, the U.S. Navy spent hundreds of millions of dollars developing a system to measure gravity gradients,” as Robin Bell explains in a 1997 article for the Leading Edge, a geoscience journal. The U.S. system “was somewhat more complex than the fictional one Clancy installed on the Red October,” Bell explains. It was also classified. Using gravimetry, “the measurement of the strength of a gravitational field,” to pilot a submarine had serious benefits for covert operations. While “using sonar involved sending off sonic ‘pings’ that would reveal your location to any submarine in the near area,” a submarine “that could navigate using a gravimeter ... would be able to, in effect, ‘run silent.’ ” In a recent piece for Offshore Engineer, Andrew McBarnet says the system was “designed ostensibly for covert navigation, but most probably also for the passive detection of gravity field changes that might indicate the presence of a silent enemy submarine.” In any case, when this technology was first developed by the U.S. Navy, it was reportedly “deployed on only a few Ohio-class Trident submarines.”
That’s where the movie version of The Hunt for Red October comes in. As retired CIA officer Bill Hadley writes in the journal Studies in Intelligence, some “senior U.S. naval officers” were “convinced the movie would do for submariners what Top Gun had done to boost the image of U.S. Navy jet fighter pilots.” And so they “provided unprecedented access to their submarines and training in submarine steering” for the movie’s stars, Sean Connery, Alec Baldwin, and Scott Glenn. “The navy even allowed the use of its subs in the film.”
And at one point in the movie, a crew member trying to make contact with the Red October says that they have detected “milligal anomalies.” A milligal is “a unit of acceleration used extensively in the science of gravimetry.” So, for anyone who understands such things, this bit of recondite jargon appears to acknowledge the use of gravimetry by a U.S. submarine.
“Tellingly,” Hadley writes, the use of such technology on U.S. submarines “was declassified a few months after Red October was released.” Though whether the movie was really responsible seems unclear to me: The technology, by that point, was fairly old, and the Cold War was nearly over. But Tom Clancy and his movie may have finally pushed it to the surface.