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Advancing an Understanding of Why the Soviet Submarine K-129 Was Lost

By Bruce Rule - Feb 20, 2015


When a submarine is lost without any direct knowledge of the cause – such as communications, the default explanation has often been the explosion of hydrogen outgassed by the main battery.

The writer has been reluctant to subscribe to such a cause unless there is evidence that an explosion actually occurred as with the USS SCORPION lost on 22 May 1968. In that case, the recovery of battery components from the wreck site indisputably established the main battery exploded BEFORE intrusion of water into the battery compartment as documented by the SCORPION Structural Analysis Group report of 29 Jun 1970.

The following discussions provide the basis for the assessment that a battery explosion was involved in the loss of the GOLF II Class Soviet SSB K-129 on 11 March 1968.


As discussed by the article “Acoustic Detections of the Loss of the GOLF II Class Soviet SSB K-129” archived on this site, three explosions occurred within – and were contained by – the K-129 pressure-hull during the minute preceeding the ignition of the first of two R-21/D4 missiles in its closed – but subsequently breached – launch tube.

Those three events are assessed to have been contained within the K-129 because of their very short durations. Had they breached the pressure-hull, their durations would have been extended by bubble-pulse energy.

Enhanced time-resolution analysis of the second, and by far the strongest of those three “precursor” events, indicates it was composed of three separate events that occurred within 0.4 seconds while the submarine was snorkeling (images of the wreck show the snorkel mast deployed) in state-six seas (extant weather data) to charge batteries . Those nearly simultaneous explosions increased sequentially in amplitude with the last energy peak having half the amplitude of the ignition of the first R-21/D4 missile. Had those events been produced by a single internal explosion, successive energy peaks – if generated - would have decreased in amplitude. (Figure 4.1, page 53, The Residual Strength of a Ship After an Internal Explosion, Department of Ocean Engineering, Massachusetts Institute of Technology, May 1988)

The sources of those three nearly simultaneous events are assessed to have been the explosion of hydrogen outgassed by the main battery and concentrated to explosive levels (above four percent) by interruptions of ventilation of the battery compartments by frequent snorkel mast wash-over and closing of the air intake valve in the state-six seas. (Access for discussions of battery explosions and fires under similar operating conditions that led to the loss of the USS COCHINO on 25 Aug 1949)

The energy level of the last of the three nearly simultaneous K-129 explosive events implied by the acoustic signal level detected at a range of about 700 nm by a single hydrophone indicates that event probably generated atmospheric over-pressure levels within the K-129 significantly higher than 20 psi, the near 100-percent fatal pressure value, i.e., a thermobaric effect. (

The linked site below provides measured hydrogen-oxygen detonation flame-front velocities for various levels of hydrogen concentration at normal atmospheric pressure (one bar). At five to 10-percent concentrations, the velocity is about 1400m/s (4600f/s). At or near that velocity, a hydrogen explosion would have traversed the 10m (33ft) fore-to-aft dimension of either the forward or the after K-129 battery compartments in about 0.007s (seven milliseconds), significantly faster than the estimated peak energy level separations of about 0.12s (120 milliseconds) between each of the three component explosions of the second precursor event. This suggests the explosions occurred in more than one space. (Note: the two battery explosions that led to the loss of the USS SCORPION (SSN-589) occurred within half a second (0.5s).

The initial event of the three nearly simultaneous events with the lowest acoustic signal level was – by inference – produced within the smallest space by volume while the third of the three nearly simultaneous events had the highest acoustic signal level by a significant margin, and, again by inference, occurred within a much larger space, probably a battery compartment.

Imagery of the wreck also shows the K-129 broke apart just aft of the sail, at or very close to frame 80 which is the location of the forward end of the after battery compartment.

(Quote) US experience (NAVSHIPS Technical Manual, Submarine Storage Batteries, Chapter 0623, March 1969 edition, sub-para 9623.721) has shown that ALL individual cell explosions have occurred while personnel were working in the battery tank during charge. (end quote).

Collectively, the above information is consistent (a plausible scenario) with the conclusion that the first of the three K-129 precursor events (at 11:58:58Z on 11 March 1968) required a crew member to enter spaces adjacent to the after battery compartment where his activities triggered a hydrogen explosion (the first of the three nearly simulaneous explosions at 11:59:43Z) that, within less than 0.4 seconds, expanded into the after battery compartment killing or functionally incapacitating the K-129 crew.

The link (causative effect) of these battery-associated explosions to the firing of the first R-21/D4 missile within its closed launch tube at 12:00:00Z cannot be assessed from the acoustic data alone. The best that can be hoped for is that other investigations now underway will provide information that, in conjunction with the acoustic data, will address this perplexing issue. Note; however, that the position of the K-129 wreck (40-04-08N, 179-57-03E) is 896 nautical miles (nm) from the Soviet Kura missile impact test range facility on the northern Kamchatka Peninsula (57-20-00N, 161-50E), and 1590 nm northwest of Pearl Harbor. The maximum range of the R-21/D4 was 755 nm.

Since the K-129 was deploying to a mid-PAC patrol station when lost, it would not be expected to actually fire two of its three missiles for any purpose and then conduct a patrol with only one missile left onboard.

It is useful at this point to review the basis for the assessment that two R-21/D4 missiles fired to fuel exhaustion within the K-129. The archived K-129 article states that analysis in 2009 of Air Force Technical Applications Center (AFTAC) acoustic data identified the firing times of the missiles (at full thrust) to have been 95.2s and 95.4s with an interval between ignitions of 361s. As discussed in PROJECT AZORIAN, THE CIA AND THE RAISING OF THE K-129 by Michael White and Norman Polmar, a Russian source - subsequent to the acoustic analysis - confirmed those R-21/D4 system parameters to have been (quote) about 94s and six minutes (360s). (end quote)


There are still missing pieces to the K-129 puzzle, and areas open to "discussion;" however, the occurrence of major internal explosions followed in 17 seconds by the firing of the first of two missiles within the K-129 pressure-hull should not be among them. It is an extraordinary circumstance that AFTAC acoustic data was still available in 2009 to provide the analysis that explained the condition of the wreck - especially the destruction of the missile section in the sail - and that has very usefully constrained credible explanations of the cause of the disaster.


"Usufruct" is a late-Latin term defined as "the right of enjoying all the advantages derivable from the use of something that belongs to another..." Such has been the case with the SCORPION and K-129 acoustic data. The writer expresses his gratitude to the individuals who provided those two data sets which permitted the first SCORPION analysis in more than 40 years and the first ever analysis of the K-129 data.

There were five individuals at Office of Naval Intelligence (ONI) in 1968 who, each working alone, could have identified the K-129 missile-firing events had the data been provided to ONI. They were Herb Jollett, George Miller, Terry Patterson, Ron Smith, and Ben Wallis. They combined great analytical talent with that absolutely critical characteristic: curiosity that often evolved into the ability to derive collateral assessments from acoustic data, i.e., they looked beyond the gram.

System analysts should note that detection is only half the game; technical exploitation is the other half, and, in times of "peace," arguably the more important half.