A $350m drillship built in the early ’70s by US billionaire, Howard Hughes, to collect ‘mineral riches’ from the ocean floor was actually a cover for the CIA to be used to lift a lost Soviet submarine, loaded with nuclear missiles, up from the floor of the Pacific Ocean, 3 miles deep
“Arizona” (erroneously called “Azorian” by the press after its Top Secret Security Compartment) was the code name for a U.S. Central Intelligence Agency (CIA) project to recover the sunken Soviet submarine K-129 from the Pacific Ocean floor in 1974, using the purpose-built ship Hughes Glomar Explorer. The 1968 sinking of K-129 occurred approximately 1,560 nautical miles (2,890 km) northwest of Hawaii. Project Azorian was one of the most complex, expensive, and secretive intelligence operations of the Cold War at a cost of about $800 million ($3.8 billion in 2016 dollars).
In addition to designing the recovery ship and its lifting cradle, the U.S. used concepts developed with Global Marine (see Project Mohole) that utilized their precision stability equipment to keep the ship nearly stationary above the target (and do this while lowering nearly three miles of pipe). They worked with scientists to develop methods for preserving paper that had been underwater for years in hopes of being able to recover and read the submarine’s codebooks. The reasons this project was undertaken are likely to include the recovery of an intact nuclear missile (R-21, also known as NATO SS-N-5 Serb), and cryptological documents and equipment.
After the Soviet Union performed their unsuccessful search for K-129, the U.S. undertook a search, and by the use of acoustic data from four AFTAC sites and the Adak SOSUS array located the wreck of the submarine to within 5 nautical miles (9.3 km). The USS Halibut submarine used the Fish, a towed, 12-foot (3.7 m), 2-short-ton (1.8 t) collection of cameras, strobe lights, and sonar that was built to withstand extreme depths to detect seafloor objects. The recovery operation commenced covertly (in international waters) about six years later with the supposed commercial purpose of mining the sea floor for manganese nodules under the cover of Howard Hughes and Hughes Glomar Explorer. While the ship did recover a portion of K-129, a mechanical failure in the grapple caused two-thirds of the recovered section to break off during recovery.