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A LOGICAL EXPLANATION AS TO THE LOSS OF USS SCORPION (SSN 589)

The recent book Blind Man’s Bluff: The Untold Story of American Submarine Espionage,e by Sherry Sontag and Christopher Drew and a previous Proceedings article title Why They Called the Scorpion Scrapiron by Mark Bradley theorize as to the loss of SCORPION. I win not comment on the above works other than stating that the authors do not have a modicum of submarine knowledge or experience and their writings reflect this deficiency. Additionally, Bradley’s title for his article is reprehensible as 99 submariners lost their lives on SCORPION.

Digressing on this matter a little further, submarining is a complex and technical business and the uninitiated can easily be overwhelmed by a plethora of evidence or data, be it fact or fable, and being unable to separate the fact from fable, founder in their various conclusions as to a probable cause for the loss of SCOR-PION. They are not alone as even seasoned submariners still harbor, in my opinion, misconceptions as hard evidence in SCORPION’s loss. I may be wrong in my theory and conclusions. However, they are in my way of thinking, logical, and do not deal in surreal assumptions or impractical hypotheses.

A more recent Proceedings article titled How the Scorpion Went Down by Captain C.A.K. McDonald, USN(Ret.), a submarine, also develops a theory as to SCORPION’s demise. I would like to comment on his article and then describe my theory as to her loss.

Captain McDonald’s theory, in summary, postulates that the propulsion battery in a Mark 37 torpedo exploded, for no known reason, which resulted in a series of events that brought about SCORPION’s loss. He theorizes that as a result of the battery explosion, the boat ascended to periscope depth and ultimately surfaced in order to ventilate the interior after the explosion and resulting fire. Some 22 minutes after the start of the casualty, the torpedo warhead exploded. This event happened while attempting to tube load and jettison the torpedo and this explosion blew two hatches out of the torpedo room causing it to start to flood. The warhead explosion also¬∑ collapsed the torpedo tubes, ramming the loaded torpedoes against the torpedo tube outer doors with sufficient force to open one or more at least partially. One tube, with an open breach door, had its outer door blown open. This series of events resulted in the uncontrollable flooding of the torpedo room. As SCORPION began to settle rapidly, one crew member donned a life jacket and -clambered out on deck through the engine room or after escape trunk. Other crew members tried the same escape route but were engulfed by seawater and trapped in the then flooding engine room. Ninety-one seconds after the torpedo warhead exploded the boat passed crush depth and the engine room and operations compartment imploded. The watertight bulkhead between the torpedo room and operations compartment was bowed into the operations compartment due apparently to the warhead explosion, but the weakened bulkhead after hull implosion was then bowed toward the torpedo room or in the opposite direction.

I find great technical fault in Captain McDonald’s theory and will comment on each postulated significant event plus other statements made in his article with reasons why his assumptions. in my estimation, are without merit.

To begin with, an internal or external torpedo explosion did not sink SCORPION. Photographs of the hull reveal no evidence of a torpedo impacting SCORPION externally and also no evidence of an internal torpedo explosion. If in fact there was an external torpedo explosion it would have totally destroyed and perhaps separated the bow compartment (torpedo room) from the rest of the hull resulting in massive and immediate internal flooding. If the warhead exploded internally, it would very likely have separated the bow compartment from the rest of the hull as the explosion would be confined within the compartment and would thus produce maximum destructive force. A Mark 37 torpedo warhead contains 330 pounds of HBX explosive. This amount of explosive (about 1.5 times more powerful than TNT) would certainly do considerably more damage than blowing a couple of hatches open and collapsing the torpedo tubes. If it didn’t then the Submarine Force was being supplied with a torpedo with marginal capability and this was not the case. To expand this subject further, when the writer was Executive Officer of USS ENTEMEDOR (SS 340) in 1964. we fired a war shot Mark 37 torpedo at ex-USS SPIKEFISH (SS 404) in Long Island Sound. By the time the debris from the explosion fell back into the water, SPIKEFISH was gone. Additionally and to further dispute the internal exploding torpedo theory, Captain McDonald refers to only one torpedo exploding. 108 This would not be the case. SCORPION carried 23 torpedoes and a reasonable torpedo load would be 14 Mark 37s, 7 Mark 14s, and 2 Mark 45s Astors (nuclear warheads). Excluding the Mark 45s because they are a different breed, the remaining 21 conventional torpedo total warhead explosive weight would amount to 7, 770 pounds or approximately 3.9 tons of high explosives. If one torpedo warhead exploded internally it would have certainly detonated all the other torpedoes and SCORPION would have been blown to bits. She was not, therefore, again, a torpedo detonation was not a probable cause for her Joss. Mention was made in the article that perhaps the explosion of the Mark 37 warhead may have been 11 low order”. This is not possible. “Low order” detonations by definition occur only in nuclear weapons where the conventional explosive associated with the weapon explodes but not the nuclear material.

An activated or hot running Mark 37 torpedo can definitely occur. When the writer was Weapons Officer on USS ABRAHAM LINCOLN (SSBN 602) in early 1961 we had a hot running Mark 37 torpedo experience. The hot run occurred while conducting a routine maintenance test on a rack stowed Mark 37. Upon attaching the test cable from the torpedo test set to the test receptacle on the torpedo and turning power onto the test set, it activated the propulsion battery. An activated battery over time generates a great amount of heat and the battery is separated only by inches from the warhead. The possibility of a warhead cook-off was cause for real concern. To further compound the problem, battery activation provides electrical power to the torpedo propulsion motor.

This motor turns the counter-rotating propellers and in our case, the torque from the motor sheared the propeller locks and we were now confronted with a runaway motor increasing in speed and with the real possibility that it could disintegrate. This eventuality would also not be in our best interests. We attempted to shut the torpedo down by changing course in order to activate the anti-circular run (ACR) switch. This was not successful as the torpedo gyro was still caged or essentially not activated and as such the ACR switch was immobilized. We finally succeeded in shutting the torpedo down by slewing the gyro using the gyro test hand crank on the test set. Gyro slewing through the test set activated the ACR switch and shut down the propulsion system. Since the 109 torpedo was a fully ready war shot, we removed the exploder, tube loaded the torpedo, and fired it into the Norwegian Sea where it resides to this day. The torpedo was activated by inadvertently plugging in the test cable to the test the receptacle on the torpedo upside down. When the test set was turned on, electrical power fired the battery squibs activating the battery and propulsion system. Upon our return to Holy Loch, Scotland we reported the casualty, and the Submarine Force was immediately informed by high precedence radio message of the problem and an ordnance alteration (OrdAlt) was rapidly developed and issued to preclude this casualty from happening to other submarines. Since LINCOLN experienced this problem in 1961 and a fix was developed then it does not seem logical that a hot running torpedo with subsequent warhead detonation would be the cause of SCORPION’s loss some seven years later.

Captain McDonald also states that one torpedo tube, with an open breach door, had its outer door blown open due to the torpedo warhead explosion with subsequent uncontrollable internal flooding. I believe that this is conjecture. Why was the breech door open and how does he know this? If the breech door was opened in an attempt to load and jettison the Mark 37 torpedo damaged by the battery explosion, it most likely was a useless evolution as explosive damage to the torpedo would most likely not permit it to fit into a 21-inch torpedo tube.

Additionally in his article, I believe there must be some sort of mistaken identity when TRIESTE II found a body on the ocean floor wearing a life jacket. SCORPION was lost in May 1968 and TRIESTE Il surveyed the wreckage commencing in June 1969. I think a human body exposed to the harsh environment of the sea for better than a year would be hardly recognizable or even exist. Additionally, a life jacket by design provides buoyancy which should preclude a body lying on the ocean floor.

Captain McDonald further states that as SCORPION passed crush depth the engine room and operations compartment imploded. This could not happen based on a previous statement that the engine room was flooding through the after escape trunk while crew members were attempting to escape. Flooding the engine room from the sea would mean that the internal pressure in the engine room would be equal to sea pressure thus negating crushing or imploding. SCORPION’s engine room was in fact rammed into the 110 auxiliary machinery room by sea pressure as she sank. The subsequent implosion of the pressure hull resulted which can only occur when sea pressure is greater than the structural strength of the pressure hull. SCORPION most likely flooded internally due to the hull fracturing at the engine room/auxiliary machinery room implosion interface and also subsequent implosion of the operations compartment.

Captain McDonald also states that the weakened bulkhead between the torpedo room and the operations compartment somehow became bowed toward the torpedo room. It was initially bowed toward the operations compartment supposedly due to the torpedo warhead explosion. Since we’ve concluded that a torpedo explosion did not occur, then what would cause the bulkhead to bow toward the torpedo room? Newton’s First Law of Motion can most likely explain the deformation. Some estimates of SCOR-PION’s speed concluded that she could have exceeded 40 knots upon impact with the ocean floor. This seems realistic considering the fact that she was flooded and a free-falling body for a distance of 11,000 feet or slightly more than two miles. Newton’s Law, for our purposes, states that a body in motion remains in motion unless acted upon by an external force. The external force, in this case, was the ocean floor, and impacting it at her estimated speed could cause equipment in the operations compartment to slam into the bulkhead bowing it toward the torpedo room. One piece of equipment in that compartment, as an example, was a 126 cell battery weighing by itself about 63 tons. This Newton’s Law is why we wear seat belts in automobiles.

A battery explosion due to hydrogen gas build-up during a battery charge and subsequent loss of battery well ventilation is a leader in probable causes of SCORPION’s loss. This is a very remote possibility but, in fact, did happen to two submarines: USS COCHINO (SS 345) resulting in her loss of Norway in 1949 and several years later, in 1955, severe damage to USS POMODON (SS 486) while in a naval shipyard. Lead-acid storage batteries are potential trouble makers, but have been in submarines since the first Navy submarine in 1900. Two mishaps in 68 years after thousands of battery charges in U.S. submarines alone is an exceptional safety record considering the potential for problems inherent in wet cell storage batteries. SCORPION’s battery appeared to be destroyed but most likely by the boat’s impact with the ocean floor rather than an explosion as explained in the previous paragraph.

There are many other theories postulated as to her loss including internal flooding through a faulty Trash Disposal Unit, a submerged collision with an underwater object, torpedoed by a Soviet submarine, an irrational act by a mentally unstable crew member, inadequate crew training, and many more. All of the above when scrutinized have serious flaws and thus are not logical causes.

Having explored scenarios that are not plausible, then what could be a logical cause and one that is supported by the available evidence? The evidence, in this case, is SCORPION’s wreckage. Starting with her wreckage and walking backward to determine what could have caused her to be in the condition that she is in seems to be a more logical approach than trying to fabricate a casualty or casualties not supported by the physical evidence. In actuality, there is no sinister mystique or far-out science fiction scenarios associated with submarine casualties. There are, however, various degrees of severity in any type of casualty and SCORPION could have encountered a situation that she didn’t immediately recognize or was slow in taking corrective action, or that any kind of corrective action on her part could not resolve her dilemma in favor of her survival.

For background information, SCORPION was a Skipjack class submarine with the following characteristics:

Displacement, tons
Length, feet
Beam, feet
Draft, feet
Torpedo tubes
Torpedoes
Main engines
Nuclear reactor Speed, knots
Complement, average
Test depth, feet
Crush depth, feet

3075 surfaced; 3500 submerged
251.7
31.5
28
6-21 inch
23-mix of Mkl4, Mk37, Mk45
2 steam turbines; approximately 15,000 shp; 1 shaft
1 pressurized water cooled SSW 20 surface; 30+ submerged
93 (8 officers, 85 enlisted) 700 (as designed) 1050

Note particularly the high submerged speed (30 + knots) and the relatively shallow calculated hull crush depth (1050 feet).

Reviewing her wreckage again, numerous photographs reveal that it is relatively intact as compared to being ripped apart by an explosion. Her bow (bow compartment) however appears to be offset from the hull centerline and partially separated from the rest of the hull but with no other major exterior physical damage with the exception that the topside escape trunk and torpedo loading hatches are missing. The operations compartment has substantial damage that appears to have been caused by the compartment crushing or imploding as a result of sea pressure. Photographs of the after a portion of the engineering spaces reveal pressure hull failure at about the juncture of the engine room and auxiliary machinery room which resulted in the engine room being literally driven into the auxiliary machinery room a considerable distance. This catastrophic hull “failure is attributed to sea pressure with resultant internal flooding of the submarine. Of interest is that the sea pressure at SCORPION’s resting place in 11,000 feet of water is 4,840 pounds per square inch or 2.42 tons per square inch.

Having explored a number of scenarios that are not plausible, then what could be a probable cause and one that is supported by the available evidence which in this case is, again, SCORPION’s wreckage. My theory for her loss is that she suffered a stern plane casualty in the dive position when at high speed either real or inadvertently imposed by the stem plantsman from which she could not recover. Bradley’s article alludes to SCORPION having “chronic problems in hydraulics, which operate both her stern and sailplanes”, but this statement is not substantiated by a reference. The court of inquiry record noted that the stern plane control system constitutes one of the most potentially hazardous systems affecting the safe operation of high-speed nuclear submarines”. This statement is 100 percent correct and this fact coupled with her high speed, in my opinion, resulted in her loss and the lives of all 99 of her crew.

A reasonable operating scenario for SCORPION on her homeward transit to Norfolk, Virginia after a Mediterranean deployment could be as follows: High speed (in the range of 30 knots), comfortable in their ability to operate the boat for consider-able periods of time at this speed, not too concerned about their relatively shallow test depth, plus perhaps complacent in that they have done this many times before and what they are doing is relatively routine. A stern plane problem could have developed from a variety of factors including but not limited to mechanical, electrical, human, or perhaps any combination of the three. Regardless of the cause, we will analyze what would happen if SCORPION was transiting at a depth of 300 feet, at a speed of 30 knots and suddenly assumed a down angle of 30 degrees due to a casualty to her stern planes. It should be noted, however, that given the above speed parameter a 30 degree down angle is not in the least excessive. On the contrary, it is quite moderate. Based on the above conditions, simple trigonometry shows that SCOR-PION’s vertical speed component based on a 30 degree down angle is one-half her actual speed of 30 knots or 15 knots straight down. A vertical speed of 15 knots equates to SCORPION increasing depth at a rate of 25 feet per second. The following table of Time and Depth is derived from this descent rate and shows that with no emergency recovery action taken by the crew, SCORPION would reach her crush depth of I 050 feet 30 seconds after the casualty occurred. Sea Pressure is also listed in the table and is a function of depth.

Time (Sec.)
0 (casualty occurs)
5
10
15
20
25
30

Depth (Feet)
300
425
550
675
800
925
1050 (crush depth)

Sea Pressure (psi)
132
187
242
297
352
407
462

There is a rudimentary emergency recovery procedure for this type of casualty, but it may not have been adequate for this class submarine. It is known as Blow, Back, and Pray. Blow all main ballast tanks to gain positive buoyancy thus slowing the descent. Back down emergency to further reduce descent speed. Put the rudder over full, which will tend to give the boat an up angle, plus the rudder also acts as a dive brake. And finally, full rise on the sailor fairwater planes, which also helps produce an up angle. Pray needs no definition. Blowing main ballast tanks as SCOR-PION descends will not empty water from her ballast tanks as rapidly as she would expect or like. As she increases depth, sea pressure also increases from 132 psi to 462 psi or 3.5 times from her transit depth to her crush depth, thus requiring more air and a longer period of time to blow water from her ballast tanks in the recovery procedure; and time, as we now see, is her greatest enemy. As a startling example, blowing her ballast tanks at crush depth would require 21 times more air pressure and for a considerably longer period of time than a normal surfacing at periscope depth.

Compounding SCORPION’s dilemma is her weight or displacement in conjunction with her high speed. A physics formula states that Momentum equals Mass (weight) times Velocity (speed). How do you stop a mass of 3,500 tons moving at a velocity of 30 knots in a distance of 750 feet or the length of 2.5 football fields in 30 seconds? This distance is the difference between SCORPION’s estimated transiting depth and crush depth. I think the answer is that it could not be done with the recovery procedures available to SCORPION and unfortunately, she proved it. Also compounding her dilemma was that she was not a SubSafe boat with retrofitted safety features as a result of the USS TIIRFSHER (SSN 593) tragic loss in 1963. Lack of SubSafe reduced her recovery capability and perhaps significantly. The Skipjack class were very high-speed submarines with a relatively shallow crush depth and this combination was perhaps not recognized by their designers at the time as a dangerous marriage.

It is not possible to even envision what happened to SCORPION when she exceeded crush depth and proceeded towards the ocean floor. At crush depth, the hull must have been relatively intact. Then, as sea pressure continued to increase during her descent, the hull most likely started to deform, twist and distort to the point where sea pressure forced the engine room into the auxiliary machinery room. This could have been followed almost instantaneously by the implosion of the operations compartment with resultant flooding. Hull deformation could have broken the dogs securing the forward escape trunk and torpedo loading hatches. Upon impact with the ocean floor, these hatches could have been sheared from their hinges. Other hatches are also missing and probably for the same reason. A periscope and two antennas are in the raised position in the wreckage and could have possibly been raised by impact with the bottom.

Based on the available evidence, it appears that a ship control problem was perhaps the most likely cause for SCORPION’s loss; but then again, we will never know. Stern plane casualties do occur. They are relatively rare but the writer experienced one on USS COBBLER (SS 344). USS CHOPPER (SS 342) experienced another that I am aware of, which was compounded by human error, that almost resulted in her loss.

Losses of submarines are painful; however, submariners learn from each loss. Looking at this further, TIIRESHER’s loss proved that lack of proper design and procedural practices on deep-diving submarines can be catastrophic and as a result, the SubSafe program was developed. SCORPION’s loss was more a lesson on how we operate submarines. This loss resulted in the development of safe operating envelopes for high-speed, deep-diving submarines, based primarily on parameters of speed, depth, and probable casualty scenarios. The loss of both submarines brought about the untimely death of 228 submariners in a short five-year span. We mom the loss of these men but because of their loss we learn and knowledge, hopefully, will preclude further submarine lessons due to material problems, operating procedures, and perhaps the unforeseen

A THANK you TO THE NSL

The Dolphin Scholarship Foundation would like to express our appreciation for the opportunity to participate in the 1999 NSL Symposium held on June 3rd and 4th. This event provided us a forum to share information about our foundation and our scholars with NSL’s many supporters.

Again we thank you for the invitation to attend the symposium and look forward to continuing our relationship with the Naval Submarine League.
Sincerely,
Cindy Giambastiani
President
Dolphin Scholarship Foundation

Naval Submarine League

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