When the K-129 was lost in the northwestern Pacific on 11 March 1968, the event produced a series of acoustic signals detected by the US Air Force Technical Applications Center (AFTAC) sea-floor sensors (hydrophones) in the central and western Pacific. The US Sound Surveillance System (SOSUS) did not identify (recognize) those signals.
AFTAC analysis in early May 1968 provided the position of the K-129 event (40-06N, 179-57E). Using that position, the K-129 wreckage was subsequently located by the USS HALIBUT (SSN-587) 2.00 nautical miles (nm), bearing 180-degrees from the AFTAC position. The K-129 wreck lies 1590 nm from Pearl Harbor, more than twice the 756 nm maximum range of the three R-21/D4 missiles the submarine carried.
Later, the Navy took the K-129 acoustic data from AFTAC before that activity could further analyze the material to determine why the K-129 was lost. The Navy then compartmentalized the K-129 data which was not further analyzed until it was recovered by the author from public domain sources in 2008, 40 years after the event.
That 2008 analysis confirmed the K-129 was lost because three explosive events contained within the pressure hull killed or incapacitated the crew allowing a simulated dual missile launch training event to become the sequential firing of two R-21/D4 missiles to fuel exhaustion within sealed - but subsequently breached - missile tubes.
Those explosive events occurred at 11:58:58Z, 11:59:43Z and 11:59:47Z. The first R-21/D4 missile ignited at 12:00:00Z (a time strongly suggestive of a planned training event, not an operational launch), developed full thrust in 1.3 seconds, and fired at full-thrust for 95.2 seconds. Five seconds after ignition, the 5000 degree F high velocity exhaust plume burned through the 0.38 inch launch tube liner (within the 0.88 inch thick QT28 nickel-steel alloy pressure hull) causing five explosive events within the K-129 pressure hull in the next 22 seconds.
Three hundred and 61 seconds after ignition of the first R-21/D4, a second R21/D4 ignited (at 12:06:01Z) within its sealed launch tube and burned at full thrust for 95.4 seconds.
As confirmed by inspection of the first compartment recovered in August 1974 by the CIA salvage ship, the Hughes Glomar Explorer, the effects of both missile exhaust plumes over a total duration of 190 seconds turned the K-129 into a burned out hulk. With the pressure-hull also breached - as confirmed by HALIBUT imagery - the K-129 sank fully flooded. There were no acoustic detections of structural collapse events, another indication of the destructive force of the missile exhaust plumes.
This acoustic-derived timeline for the events responsible for the loss of the K-129 - already derived - was confirmed in 2008 by a Russian source who stated the R-21/D4 missile burn time to maximum range (fuel exhaustion) was (quote) about 94 seconds and six minutes between launch events had been demonstrated during one of the first test launches (end quote).
As discussed above, the values derived from analysis of the acoustic data were 95.2 and 95.4 seconds for the missile firings at full thrust while the acoustically-derived launch interval was only one second longer than that identified by the Russian source, i.e., 361s versus 360s.
This was not a difficult analysis. It could have been derived in 1968 even without independent confirmation of the R-21/D4 missile launch system parameters. The temporal spacing of precisely repeating events of the same 95 second duration that started at exactly 12:00:00Z and 361 seconds later - together with HALIBUT imagery of the wreck that showed breaching of the pressure hull below the missile compartment - would have admitted to no other explanation. Such was the dark side of the Navy compartmentalization which prevented those US agencies concerned with approving the salvage effort - code-named Project Azorian - from knowing the condition of areas within the K-129 wreck from which they hoped to the recover communications equipment and documents, i.e., those spaces had been subjected to 5000 degree F temperatures for more than three minutes.For more information on the design, construction and execution of the K-129 recovery system and that operation in 1974, read "Project AZORIAN, The CIA and the Raising of the K-129" by Norman Polmar and Michael White and view the Michael White film, "AZORIAN: The Raising of the K-129" upon which the book is based. The author of this article supported both efforts on a pro bono basis, i.e., was NOT compensated for his contributions.