Two Soviet Submarine Disasters
By Bruce Rule - July 24, 2013
TWO SOVIET SUBMARINE DISASTERS by Mr. Charles J. Baker and Mr. Bruce Rule
Chuck Baker is a veteran US Navy submariner who served on fast attack submarines in the 1980's and later served as a surface warfare officer in the early 1990s. Chuck's background is in applied engineering and he holds a Master's Degree in Mechanical and Aerospace Engineering. He currently works at NASA's Jet Propulsion Laboratory as a senior systems engineer and is a team member on NASA's Mars Science Laboratory.
Bruce Rule: as already posted
First Disaster: the MIKE Class Soviet SSN (K-278), lost on 7 April 1989
FIRE AT SEA, THE TRAGEDY OF THE SOVIET SUBMARINE KOMSOMOLETS (NATO: MIKE) is a remarkable book about a remarkable submarine. Written by D.A. Romanov, the deputy chief designer of the MIKE, and copyrighted in 2006, the book (hereafter ROMANOV) provides detailed technical information on the design characteristics of the MIKE that could not have been published during the Soviet era.
It is not the purpose of this article to review ROMANOV but to discuss several important conclusions that are based on information in the book which were not specifically addressed by the author.
As discussed in ROMANOV, the MIKE was lost when a fire in the aft-most compartment (seven) melted non-metallic connections in the high-pressure air and hydraulic lines allowing their release into that compartment which resulted in a (quote) blast furnace (end quote) with estimated pressures 20 times normal and combustion temperatures at least a high as 1600 (F), (ROMANVOV, pp. 103). Those conditions caused the titanium pressure-hull to recrystalize and burn through (breach) to permit flooding. Sea water near the stern was observed boiling.
The resulting flooding had progressed from compartment seven as far forward as compartment three when the MIKE sank down by the stern at 1708 local on 7 April 1989 in the far northeastern Norwegian Sea (73-43-17N, 13-15-51E).
When the MIKE sank, five men were still onboard. Four entered the escape sphere in the sail which could not be released, probably because of the stern-down attitude which would have prevented the sphere from rising from its vertically-mounted containment area. According to the single survivor, that stern-down attitude increased sharply before lessening as the MIKE sank toward the bottom at a depth of 5530-feet.
The survivor from the sphere stated (ROMANOV, pp. 171) that (quote) suddenly, there was shock beneath us, like a bomb exploding, followed by a second vibration. (end quote) Although there are alternate explanations for these two events, the most likely not discussed in ROMANOV is bottom impact, first by the stern and then by the rest of the submarine pivoting on the grounded stern. This sequence of events, which leveled the submarine as confirmed by subsequent imagery and observations from Soviet MIR submersibles released the escape sphere.
If the MIKE impacted the bottom 10-degree down by the stern and sank at about 13 knots, a value determined for the USS STERLET (SS-392) during an instrumented sinking on 31 January 1969, then the two MIKE bottom impacts should have been separated by two to three seconds.
The released sphere designed to hold the entire crew of 64 rose to the surface in (quote) one to two minutes (end quote) where the pressure-seated topside hatch blew open (because of over-pressure within the sphere) permitting the survivor to escape. (A weight/displacement analysis suggests about three minutes.) Another man, who also was ejected, died from his injuries while other two including the Commanding Officer - in the sphere were either moribund or dead. They had failed to connect their emergency breathing systems and were overcome by toxic fumes and the atmospheric overpressure within the sphere which increased the toxicity of the fumes. The sphere, which then flooded and sank, was subsequently located about 300-feet from the MIKE wreck after rising and then sinking 5,500-feet.
If the MIKE sank at 1708 local and had the same 13-knot sink-rate measured for the STERLET, bottom impact should have occurred about 1712, a value consistent with then Soviet press reports of the surfacing of the sphere at about 1715.
The normal maximum operating depth (test-depth) for the titanium-hulled MIKE was 1020m (3350-feet) with a never exceed depth of 1250m (4100-feet), and an estimated pressure-hull collapse depth of 1500m (4,900-feet).
Page 175 of ROMANOV shows the photograph of a clock recovered from the MIKE wreck in 1992 and now on exhibit in the Russian Naval Museum in St. Petersburg. That clock stopped at 17:22;30 or about 10 minutes after the probable MIKE bottom impact.
This circumstance indicates the area within the MIKE pressure-hull where the clock was located did not collapse until subjected to a pressure of 2,460 psi for those 10-minutes. Although the design pressure limit of the MIKE interior bulkheads (specifically those contiguous to compartments six and seven was 142 psi (ROMANOV pp. 102), the clock provides clear evidence that one bulkhead survived temporarily at about 17 times that pressure.
During the instrumented sinking of the STERLET, the torpedo room bulkhead the only sealed compartment collapsed at a depth of 1200-feet, three times the test-depth of the pressure-hull. The energy released by that event was equal to the explosion of 840 pounds of TNT at that depth.
Chapter 2 of COLD WAR SUBMARINES by Norman Polmar and K. J. Moore states that (quote) the end (torpedo room) compartments of WWII US diesel submarines were rated at 1,100-feet to facilitate the use of the McCann rescue chamber (end quote) mated to the escape trunks in those compartments. See Note (1). The STERLET keel was laid down on 14 July 1943.
During a 1993 Russian survey of the MIKE wreck-site, a 20-foot hole was noted on the starboard-side of the first compartment, the torpedo room.
These circumstances indicate the clock was recovered from the torpedo room through a hole in the pressure-hull or was ejected through that hole and was recovered from the bottom. It is concluded the MIKE torpedo room bulkhead could withstand the same pressure as the pressure-hull for the same reason as the STERLET design: to provide a refuge for those crew members unable to enter the escape sphere who might then be rescued via the MIKE forward escape trunk. The Romanov information indicates both the torpedo room pressure-hull and the bulkhead between the torpedo room and the second compartment survived at a depth of 5,530-feet for about 10-minutes before collapsing.
It is probable the MIKE torpedo room pressure-hull and bulkhead collapsed nearly simultaneously because the shock-wave from the first collapse event would have propagated through the pressure-hull to the site of the second collapse at the speed of sound in titanium (19,900 f/s or 13,600 mph). Already stressed beyond design limits, the second collapse site could not have withstood the shock-wave from whichever site collapsed first.
Based on an estimate that the hole in the torpedo room pressure-hull was about 30-feet forward of the torpedo room bulkhead, the shock-wave generated in the pressure-hull by the first collapse would have reached the site of the second collapse and triggered that collapse in about 0.002-seconds, or about three times faster than the velocity of the water-ram expanding at supersonic velocity through the torpedo compartment from the site of the first collapse.
Second Disaster: the NOVEMBER Class Soviet SSN (K-8), lost on 12 April 1970
When the NOVEMBER Class Soviet SSN (K-8) sank in the Bay of Biscay (47-25N, 19-40W) on 12 (not 11) April 1970 as the result of fires, an associated collapse event was acoustically detected by a SOSUS array in the western Atlantic at 04:04:44Z. (This information was derived from acoustic data that had been in the public domain for more than 40-years but was reported for the first time in 2012.)
The K-8 sank, down by the stern, with 52 of the crew still on board. They had previously been evacuated to a Soviet surface ship but were ordered back on board by the Beach. Shortly thereafter, the K-8 on the surface in rough seas lost stability and sank.
Analysis of the acoustic signal (bubble-pulse frequency) indicated the NOVEMBER collapse event occurred at a depth of 2,020-feet (900 psi) with an energy release equal to the explosion of 1,050 pounds of TNT at that depth. Based on the MIKE and STERLET data, that event is assessed to have been the collapse of the NOVEMBER torpedo room bulkhead and/or the torpedo room pressure-hull. The published test-depth of the NOVEMBER Class was 985-feet.
Since it is probable all modern Russian submarines have torpedo room bulkheads with the same depth capability as their pressure-hulls, and also have a reserve buoyancy greater than the volume of the torpedo room, the breaching of the torpedo room pressure-hull by a weapon and the flooding of that compartment even at significant depth will neutralize the the submarine's ability to fire forward torpedo tubes but will not necessarily result in the loss of the submarine if the torpedo room was sealed prior to weapon impact.
The empiric relationship that exists between the volume of a collapsing structure and the bubble-pulse frequency (the alternating compression-expansion cycle of air contained within the collapsing structure) permits determination of the depth of the event. In turn, that depth value and the bubble-pulse frequency provide the size of the energy release expressed in pounds of TNT required to create that frequency at that depth.
Such forces are produced when potential energy in the form of hydrostatic (sea) pressure is converted almost instantaneously to kinetic energy, the motion of the water which enters structures that collapse at great depth at supersonic velocity, e.g., 2,600 mph in the case of the USS THRESHER (SSN-593) which collapsed without prior flooding at a depth of 2,400-feet.
In the case of the NOVEMBER, all internal structures in the unflooded torpedo room were destroyed in less than 0.04-seconds as determined from the frequency of the collapse event bubble-pulse.
When the USS SCORPION (SSN-589) collapsed at a depth of 1,530-feet, the engine room telescoped into the auxiliary machinery section a distance of about 50-feet. The frequency of the SCORPION collapse event bubble-pulse (4.46-Hz) indicates the telescoping occurred within no more than 0.112-seconds which equates to an average velocity of about 300-mph for the forward motion of the engine room.
As previously discussed, submarine pressure-hull collapse events that occur at great depth occur too rapidly to be perceived by those onboard.
This article is based entirely on unclassified acoustic data and information recovered from documents in the public domain.
(1) USS SCORPION (SSN-589) RESULTS OF NOL DATA ANALYSIS (U) (NOLTR ser 69-160 of 20 January 1970) states that the STERLET after escape trunk collapsed at a depth of 9,100-feet. The forward escape trunk collapsed at 10,300-feet.