1. The Bold Idea Behind Operation Ivy Bells
In the shadowy depths of the Cold War, one daring idea set off one of the most audacious intelligence operations in U.S. history. James F. Bradley Jr., the Undersea Warfare Director for the Office of Naval Intelligence, suspected that the Soviet Navy’s submarine base at Petropavlovsk on the Kamchatka Peninsula was linked to the Russian mainland via a deep undersea cable. Because Soviet cryptographers were swamped and had to prioritize, much of the cable traffic wasn’t even encrypted. Bradley recognized an amazing opportunity: if the U.S. tapped into that cable, it could have a direct pipe into the center of Soviet naval communications.
2. USS Halibut: From Missile Sub to Spy Sub
The USS Halibut had already had one life as a nuclear-powered missile submarine. As missile technology advanced, her initial mission was rendered obsolete. Instead of sending her to retirement, the Navy radicalized Halibut’s appearance. Her missile bay was converted into a clandestine intelligence center referred to as “the Bat Cave,” equipped with sophisticated surveillance equipment, such as an unusual 24-bit UNIVAC computer, sonar arrays, and a seafloor imaging system. Unique thrusters and anchoring winches enable her to anchor on the seafloor, and a secret deck chamber houses saturation divers for deep-sea operations.
3. Breaking Barriers: The Technology Behind the Tap
Tapping a live, highly used Soviet underwater cable—120 meters below the surface—was no easy task. The initial successful tool was a three-foot magnetic induction sensor able to take data without penetrating the cable, reducing the chances of detection. Heartened by this achievement, engineers at Bell Labs created a more durable one: a six-ton nuclear-powered recording device called “the Beast.” It could record weeks’ worth of multi-line conversations. Submarines such as Halibut regularly and perilously made forays into Soviet waters to pick up tapes and maintain the machine.
4. Discovering the Cable: A Game of Clues and Courage
Finding the underwater cable involved a combination of clever reasoning and boots-on-the-ground (or fins-in-the-seawater) courage. Bradley hypothesized that, as in America, the Soviets would label underwater cables with placards telling ships to keep clear of anchoring near them. Halibut’s crew swept the Kamchatka coast and finally detected Cyrillic placards on a faraway beach. Employing remotely operated underwater vehicles affectionately dubbed “Fish,” they swept the ocean floor until the cable was located. Then came the trickiest part: the sub quietly lay down on the seabed, and divers placed the wiretap—all without spooking Soviet troops patrolling in the area.
5. The Divers: Courage Under Pressure
No device could do the job of human divers in Operation Ivy Bells. Specialized saturation divers resided in a pressurized chamber aboard and breathed a mixture of helium and oxygen to exist at such depths. Their work was risky, and each dive posed the risk of decompression sickness or death. One day, a storm knocked Halibut’s anchors loose, and the sub suddenly popped up while divers remained outside. In an instant decision, Captain John McNish flooded the sub to smash it down onto the seabed to save the lives of the divers, but almost lost the vessel itself. The mission was as much a test of human courage as it was technological creativity.
6. The Intelligence Goldmine
The return was staggering. The National Security Agency (NSA) got tape after tape of Soviet naval conversations—raw, unfiltered, and sometimes unencrypted. The tapes contained everything from deployments of the fleets to internal discussions and even personal phone calls between officers and their homes. The raw honesty of the communications provided the U.S. with unprecedented access to Soviet thinking and informed American military planning, including decisions made at the pivotal SALT II arms control negotiations.
7. The End of the Line: A Spy’s Betrayal
The operation lay concealed for years, weathering storms, close calls, and the constant risk of Soviet detection. But ultimately, it was not detection or technology that revealed it—it was betrayal. In 1985, KGB defector Vitaly Yurchenko disclosed that Ronald Pelton, a cash-strapped former NSA analyst, had sold the cable tap secret to the Soviets for $5,000, with additional money yet to follow. The Soviets promptly pulled out the device, and the operation was finished. It was a chilling reminder that the most advanced intelligence operations can be undone by one act of betrayal.
Operation Ivy Bells was a success of creativity, guts, and oceanic boldness. It showed how far the United States was willing to push in an effort to comprehend its Cold War foe—and just how tenuous even the most secure operations can be when human confidence is shattered. Today, it is one of the most intriguing and high-stakes espionage missions ever attempted below the surface of the sea.
