Project Azorian has goal marine salvage
Project Azorian (also called "Jennifer" by the press after its Top Secret Security Compartment) was 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 1,600 miles (2,600 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, or $4.7 billion today.
The US designed the recovery ship and its lifting cradle using concepts developed with Global Marine (see Project Mohole) that used their precision stability equipment to keep the ship nearly stationary above the target while lowering nearly three miles (4.8 km) 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 that this project was undertaken included the recovery of an intact R-21 nuclear missile and cryptological documents and equipment.
The Soviet Union was unable to locate K-129, but the US knew where to look, based on data recorded by four Air Force Technical Applications Center (AFTAC) sites and the Adak Sound Surveillance System (SOSUS) array. The US identified an acoustic event on March 8 that likely originated from an explosion aboard the submarine. The US zeroed in on the location to within five nautical miles (5.8 mi; 9.3 km).  The submarine USS Halibut located the boat using the Fish, a towed, 12-foot (3.7 m), two-short-ton (1.8 t) collection of cameras, strobe lights, and sonar that was built to withstand extreme depths. The recovery operation in international waters about six years later used mining for manganese nodules as its cover. The company was nominally owned by Howard Hughes, secretly backed by the CIA, who had paid for the construction of the Hughes Glomar Explorer. The ship recovered a portion of K-129, but a mechanical failure in the grapple caused two-thirds of the recovered section to break off during recovery.Eyewitness account
W. Craig Reed told an inside account of Project Azorian in his book Red November: Inside the Secret U.S. – Soviet Submarine War (2010). The account was provided by Joe Houston, the senior engineer who designed leading-edge camera systems used by the Hughes Glomar Explorer team to photograph K-129 on the ocean floor. The team needed pictures that offered precise measurements to design the grappling arm and other systems used to bring the sunken submarine up from the bottom. Houston worked for the mysterious "Mr. P" (John Parangosky) who worked for CIA Deputy Director Carl E. Duckett, the two leaders of Project Azorian. Duckett later worked with Houston at another company, and intimated that the CIA may have recovered much more from the K-129 than admitted publicly. Reed also details how the deep submergence towed sonar array technology was used for subsequent Operation Ivy Bells missions to wiretap underwater Soviet communications cables.
The documentary film Azorian: The Raising Of The K-129 was produced by Michael White and released in 2009. It features interviews with Sherman Wetmore, Global Marine heavy lift operations manager; Charlie Johnson, Global Marine heavy lift engineer; and Raymond Feldman, Lockheed Ocean Systems senior staff engineer. They were the three principals in the design of the Hughes Glomar Explorer heavy lift system and the Lockheed capture vehicle (CV or claw). They were also on board the ship during the mission and were intimately involved with the recovery operation. They confirmed that only 38 ft (12 m) of the bow was eventually recovered. The intent was to recover the forward two thirds (138 ft [42 m]) of K-129, which had broken off from the rear section of the submarine and was designated the Target Object (TO). The capture vehicle successfully lifted the TO from the ocean floor, but a failure of part of the capture vehicle on the way up caused the loss of 100 ft (30 m) of the TO, including the sail. Norman Polmar and Michael White published Project Azorian: The CIA And The Raising of the K-129 in 2010. The book contains additional documentary evidence about the effort to locate the submarine and the recovery operation.