Friday, January 8, 2010
Another example of clever searching from that submarine book
In the previous post on Blind Man's Bluff: The Untold Story of American Submarine Espionage, by Sherry Sontag and Christopher Drew, I mentioned an example from the book of a clever approach to finding a needle in a haystack (the use of Bayesian analysis to find a lost nuclear weapon). There was another example in the book, that employed an entirely different sort of cleverness.
In 1970, James Bradley, the director of undersea warfare at the Office of Naval Intelligence, thought there must have been an undersea telephone cable connecting the Soviet missile sub base at Petropavlovsk, on the Kamchatka peninsula, to the Russian mainland across the Sea of Okhotsk. Bradley figured such a cable would be at most 5 inches thick. How do you find a 5 inch thick cable at the bottom of a sea?
It turned out that, as a boy, Bradley had killed time hitching rides on riverboats on the Mississippi, and he remembered seeing signs on the shore occasionally that warned, "Cable Crossing: Do Not Anchor". So (after some political maneuvering the book recounts in detail) Bradley sent a submarine crew to look for a similar sign on the shore of the Sea of Okhotsk. They found one, found the cable, and successfully tapped it. The Soviets hadn't coded their communications through the cable, because they never expected it would be tapped.