"Project Jennifer" wasn't a submarine - it was the fake CIA Top Secret Compartment code name incorrectly used by the media which referred to the CIA's actual project, codenamed "Project Azorian".

Azorian was arguably the most ambitious engineering, salvage, and intelligence operation of the Cold War, given the task of raising a submarine that was sitting on the bottom of the ocean over 3 miles down without the Soviets finding out.

Azorian aimed to raise the sunken Soviet Golf II-class ballistic missile submarine K-129, which had been lost at sea under still unknown circumstances (though plenty of conjecture) in 1968. Though the Soviet Union launched an exhaustive search mission, they never found her location.

However, United States SOSUS arrays (hydrophone arrays strategically placed at various locations on the bottom of the ocean) picked up her destruction, and analysts were able to triangulate K-129's position fairly quickly, northwest of Hawaii. USS Halibut (SSN-587), a specially outfitted submarine which had been converted for special operations use and had multiple exterior light and camera arrays, was dispatched to the area, and found the K-129 within days. After taking literally thousands of pictures, the CIA hatched a plan to raise the K-129, turning to defense contractor Global Marine, and its owner, billionaire Howard Hughes. The ultimate goal was to raise the K-129, and hopefully recover her nuclear weapons, cryptographic machines and codebooks, and other equipment for analysis.

It took several years to finish the Hughes Glomar Explorer, which was designed and built specifically for the singular task of raising the K-129, which began in 1974. Several Soviet sailors' remains were recovered during the operation, and a formal burial at sea was filmed, in hopes of one day giving it to the Russians to show we had respected their dead. The video was given to Russian President Boris Yeltsin in the early 90's.

A video was released earlier in 2011 by Michael White detailing the operation, with animation and interviews with Global Marine engineers involved with the program.