Bruce mbabele@999info.net
It has been 2 1/2 years since the ROV trip. Now, due to an unusual sequence of events, we have been provided some insights that may add significantly to our understanding of the Grunion loss.
I want to introduce to you 87-year-old Cmdr Charlie Tate. Charlie has a background uniquely suited to understanding the elements of the confrontation between the Grunion and the Kano Maru. He started the beginning of World War II on a cargo ship (same tonnage as the Kano Maru) moving material to Dutch Harbor. Around 1943 he joined the USS Gato and eventually became the chief of that sub. When he was 11 he earned money by dynamiting stumps which he then hauled, by donkey, to the Hercules Dynamite factory. The significance of what he learned from that dynamite experience will show up later. His words:
I in no way consider myself the best authority on submarine warfare however I have observed, conducted, evaluated, and or participated in literally dozens of torpedo approaches in war and peace time. With absolutely no input from Grunion and conflicting information from Japanese sources other plans may be offered. My comments are offered only as another possibility as to what could have occurred
What Charlie brings to the table is the ability to study current thinking and point out aspects that are inconsistent with his experience. He has spent considerable time reviewing John Fakan’s anaglyph photos and analyzing the confrontational path suggested in current thinking.
Point 1. Current thinking on the path of the two vessels puts the Grunion ending up south of the Kano Maru in a position where escape would be hampered by McArthur’s Reef. He argues that would never have happened. The Grunion started off in a excellent position and it would be ludicrous to move away from that area. A torpedo attack is a carefully planned operation. CT’s words:
When a target is sighted the Contact Phase of a torpedo attack begins. The direction of the relative movement of the target must be determined and it is accomplished by observing the angles on the bow or by heading towards the target and observing the direction of bearing movement. The duration of this procedure usually takes about five minutes to gather the information required. The next procedure is the Approach Phase or to maneuver aggressively and tenaciously to close the target range to the best position to commence the Attack Phase. This position will be relative to the enemy and will vary depending on sea condition, detection devices in use by target, speed of target, course of target, presence of air or sea escorts, or target tactics( zig-zag). The target had none or was not using any of these diversionary devices. We are now at the firing point to start the Attack Phase. Grunion Conning Officer(CON), the commanding officer when at Battle Stations, made the last quick look to add final visual input to the firing solution to verify that sonar, Torpedo Data(TDC), and visual were all in agreement. If they were the order to fire was given; “fire one“, five seconds later, “fire two. and the torpedo run time to target is reported to CON. Sonar would report No1 hot straight and normal, then No2 hot straight and normal. At the expiration of run time CON would “up scope” to witness the hit and report any change in angle on the bow. In this case one torpedo stopped the screws of the target and sonar would have reported “screw count zero” meaning the screws were no longer turning. If the target was firing deck guns any “Shots “ would be seen, any fairly close hits would be heard by sonar and if close enough also by ear. The TDC would have continued the solution progressing from last data received. A quick look would have seen the drastic change of angle on the bow, sonar reports no appreciable change in bearing, or range, and advance target track line was minuscule, all verifying that target was dead in the water. Grunion was probably considering reloading at least the two upper torpedo tubes for the target was still afloat.
Point 2 He argues that the Kano Maru then drifted not west but in a clockwise manner and because there was neither land nor wave reference that the crew of the Kano Maru mistook the movements of the Grunion for movements of their own ship. Charlie’s words
The Kano Maru was south of Grunion on a westerly course at a speed of 15 knots. She reported that the torpedo tracks were sighted approaching forward of her starboard beam. She immediately applied hard right rudder and turned toward Grunion to split the track and also present a silhouette vice a broad side target. Standard steering systems are a movement on order device and the rudder would remain in its last position until ordered otherwise. When the torpedo struck in her machinery space she lost propulsion power, and steering. With the momentum of 15 knots and hard right rudder applied means she will circle continuously to starboard until losing momentum. The distance of travel is estimated to be 1200/1500 yards. She is firing her deck guns haphazardly at what she thinks is a moving submarine periscope. Grunion knew immediately from two sonar systems that target screws had stopped and she was going nowhere. Kano-Maru had four more torpedoes fired (three duds) at her from different relative bearings making her believe Grunion was moving extensively and not realizing that her own circling movement was responsible for the bearing changes.
It was also known that Kiska could hear gunfire and that aircraft were based there. The thought of going to Battle Surface to finish off the Kano Maru was not seriously considered for this meant opening hatches and exposing at least ten men on deck. Visibility was restricted which would give aircraft the advantage of getting very close before detection. A small hole in the pressure hull could be disastrous or the loss of ten men in a forced dive was just not worth the risk. Four more torpedoes were fired in this attack, one passed under starboard bow, three more at portside. Grunion had no reason to maneuver excessively to remain in firing position for the last four shots as no evasive movements were required. The target was slowly moving with no propeller noise so all Grunion had to do was remain at firing range and keep her bow pointing in the general direction of target.
Point 3 Charle’s third point: There was never a broach. The Kano Maru was shooting at the wave caused by a massive bubble when the Grunion imploded. His words:
Kano Maru reported seeing rolling of the water like a submarine surfacing and fired at it with her deck gun then immediately seeing a huge eruption and a column of oil spraying into the air. This could not have been caused by damaging the periscope shears. There is absolutely no vital machinery, piping, fuel tanks, air systems, hydraulic systems or anything else in the conning tower area that could cause fuel and air to spurt like reported. Whatever caused this commotion had to be the eruption of fuel oil tanks.
Jon Britton pointed out a long time ago that with the shears above water there is no wake just a ripple. See http://999info.net/Grunion/AttackInfo.pdf about 3/4 of the way down.
Point 4: The damage to the shears was so extensive that it could not possibly have been caused by a 3 inch shell a shell that contains the equivalent of 1 ½ pounds of dynamite. The shell weighs 17 lb and travels 2700 ft sec. Because it is designed for aircraft when it explodes that linear momentum is transformed into spherical momentum, something like a hand grenade. Charlie:
Photographs of the aft upper shears show severe damage that might be caused by a heavy fast moving mass. They were pushed forward bending the shears lifting up the deck and shearing off the connecting bolts. What could have caused this? A circular running torpedo possibly. Malfunctioning torpedoes were prevalent at this stage of WWII. Inconsistent depth control, malfunctioning exploders resulting in duds, and the dreaded circular running torpedo were reported in a very high percentage of firings.
Point 5 This is a slight variation on earlier thinking. Note that the USS Gato had experienced a locked rear dive plane. CTs words:
Grunion was at periscope depth (shears 16 ft down) deciding how to finish off the Kano Maru when something smashed into her shears. The damage was extensive and very loud, it shook the boat but watertight integrity was not breached. The CO knew no surface ships were in the vicinity and the Kano Maru deck gun was no threat so the logical deduction was an aircraft had sighted him at periscope depth and dropped a bomb. In anticipation of another bomb he made the decision to “take her down” to a deeper depth. This not a normal change of depth order to the diving officer. This “take her down” order means as quickly as possible. Bow and stern planes are placed on full dive, all full ahead is ordered, negative tank is flooded, and a steeper than usual down angle is ordered. Negative tank holds 20,000 lbs of water and that destroys neutral buoyancy instantly, the planes tilt the boats bow down, full speed on the propellers drive her down. At about 65 feet negative is blown dry. This takes about 15 seconds. With negative empty neutral buoyancy is restored. But speed and angle are still driving the boat down. We are now passing 100 feet. Full rise on bow and stern planes is ordered. All ahead 1/3 is ordered. Normally this will allow the boat to level and the descent can be stopped around 150 feet. However if something goes wrong, like the stern planes lock on full dive, emergency measures must be applied INSTANTLY. If the down angle reaches 30 degrees, all back full is ordered and all main ballast tanks are blown. A down angle of 30 degrees or more makes it very difficult for men to remain in position so they can perform their duties. When “blow main ballast” is ordered the man on the high pressure air manifold has eight or more valves (depending on fuel on board) to open by hand [and they require a handle (which could be dropped] and must be opened rapidly in order(1-8) to bring the bow up. If the controller man on speed control gets thrown out of position and can’t answer all back full. Disaster. Grunion had a test depth of 300 feet an out of control dive can reach that depth very quickly.
The last torpedo Grunion fired was a miss and it could have made a circular run and hit the shears. The time frame allows this.
Several witnesses reported seeing a black rod shoot up and then fall back. Approximately 15 foot of the torpedo is a container that holds 3000 pound air used for powering. When empty that container would float and it is coated with a black glop. That may have been the black rod that shot up and then fell back.
If the circular run hypothesis holds up considering that a dud torpedo hit the small profile of the Grunion it creates an almost unimaginable end to this story.
Charlie presents some rather dramatic and interesting changes in the thinking about the loss. However like all of these hypotheses we need to aggressively search for inconsistencies or we can believe almost anything
Comments please.
Some Additional Information
First Some Philosophical Ramifications
Imagine there is a small fire. Somebody picks up a container of gasoline and tosses it on the fire and lo and behold the fire is extinguished. If you observed this there would be a double take. This is NOT consistent with experience. You cannot put out fire with gasoline.
On the other hand if you were three years old this would not be inconsistent.
Consistency and inconsistency are LEARNED associations.
The gasoline-extinguisher is similar to the shooting of a 3 inch shell, which hits washing wave, which then simultaneously sends a massive amount of oil to the surface. The difference is that unless one understands the limited explosive power of a 3 inch shell and the location of the fuel tanks on a submarine that does not appear inconsistent. Consistency and inconsistency are LEARNED.
To recognize the inconsistency existent in the four translations, some knowledge of the physics of a sub, the relative power of explosives and other background needs to be understood.
In addition we need to judge whether there was recognition of the oil OR the shears. One of the two is wrong.
How do we determine what was observed. Most important we look for inconsistencies. Remember that consistency and inconsistencies are LEARNED; they are not part of the real world. In that light it would appear wise to assign credibility to those with experience, to those who have LEARNED the appropriate consistencies and inconsistencies. As a starter the presumption of credibility lies with C Tate.
Note that the translations used words such as “appeared” or “seem to” in reference to the sub. where when they talk about the oil it was quite clear cut. The fact that the damage to the shears was much greater than that that could have been caused by a 3 inch shell leads us to recognize that the damage must have occurred underwater which could have lead to implosion and damage to the fuel tanks.
One other bit of supporting consistency. If you look at Jon Briton’s Attack info (999info.net>Grunion>Attack Info.pdf about ¾ of the way down) you will see what shears create as a wave, It is a ripple not a washing wave. A washing wave is what you see at the beach or what is created when a large amount of water is disturbed for example when a massive bubble rises to the surface.
Some Specifics About the Charles Tate Hypothesis
If the Tate hypothesis is determined to have credibility it adds a great deal to the understanding of loss of the Grunion. I want to summarize below the elemental hypotheses behind it.
I think that it’s easier to understand if we work backward in time.
1. There is general agreement (from studying John Fakan’s 3d anaglyph photos) that whatever damaged the shears came in over the stern. Charlie Tate hypothesizes that a 3 inch shell could not possibly create that much damage particularly when the shears were almost certainly 16 feet below the surface. (See Status Report 2/11 blog entry below) Charlie’s background is unique for that understanding having worked with dynamite as a youngster and having used a gun almost identical to that on the Kano Maru many many times. To help support his hypothesis he presents a photo of the shears of the USS Torsk which was rammed by an approximately 2200 ton destroyer. The damage is similar to that of the Grunion. However, the momentum is dramatically different than that from a 3 inch shell. Study the photo below carefully
2. Recognizing that the Grunion was almost certainly at periscope depth by process of elimination about the only thing that could cause that amount of damage would be a circular run DUD torpedo. A bomb or an exploding torpedo would have created much more damage and a mine is very unlikely.
3. Some will suggest that the sub had broached or was surfacing. The evidence behind that is from Aiura’s report. There are several translations of that report two of which indicate LARGE amounts of oil. That oil could only come from the fuel ballast tanks 45 feet down. They could not have been damaged by a 3 inch shell. I think it’s safe to say that none of the translations indicate a positive clear cut recognition of a surfacing submarine. I have copied the pertinent parts of those four translations below. Bottom line, what was observed was a massive bubble from the imploding sub.
• Vern Miller translation: Time: 0610 hrs. Kano Maru again saw the periscope at a range of 400 meters (135° left) and again opened fire with her cannon and machine guns. The periscope at this time approached Kano Maru’s stern and began to surface slightly so that what seemed to be the top of the conning tower, making a wake, was visible. One 8 cm shell hit the tower. Water splashed up with a dull explosion and much oil erupted from the top of the tower [3]. This was the 84th shell fired by Kano Maru. The Japanese crew yelled Bansai”
• Unknown translation: 0610 A periscope of this attacking submarine was sighted 135 degrees port, 400 meters away from the ship. The Kano commenced firing 8cm guns and 13 MGs at below the periscope. They confirmed direct hits and exploding sound and tremendous amount of dark brown liquid was flushing out from the sea.
• Howland translation: At 0610 we once again got the periscope in our sights at 135 degrees left, at a distance of about 400 meters. The 8cm and 13mm guns on the front deck once again commenced firing. The enemy sub, with its periscope visible, lazily floated past the damaged Kano Maru, as if mocking us. This was most infuriating indeed. Then the sub began to surface, and ripples appeared around what looked like the control tower. Having been unable to sink us with torpedoes (loading up spare torpedoes at this point would have taken a good deal of time), were they now going to try to finish us off with guns? Or were they simply grossly underestimating us?It was at this moment that an 8cm bullet struck the submerged area of the enemy sub. Spray and the dull thud of an underwater explosion followed, as well as a swell of heavy oil. Once we realized that we had indeed sunk the sub, the entire crew gave a ‘banzai’ yell of triumph.
• Yutaka translation: 06:10 Then we find the periscope at left 13 5 degree about 400m distance. Our forecastle 8cm gun and 13mm machine gun again started the fire. The sub kept the periscope up and moved calmly ignoring damaged KANO MARU. We clenched our fists but had no way to do. [*3] Then the sub seemed to begin to surface. The conning tower made ripple on the surface and the wave began washing the conning tower. I think the sub was unable to sink KANO MARU by the torpedo ( reload the stocked torpedo to the tube needs much minutes ) so finish KANO MARU by its gun or the sub thought KANO MARU could do no harm any more. Just then a 8cm gun shot hit the washing wave, made water column and dull water explosion sound. Also we saw the swell of heavy oil. All crews shout ‘BANZAI
4 There is general agreement that the Grunion lost depth control as result of a jammed stern dive plane. (It happened to the Gato) In theory it’s possible to recover from such a situation by blowing the bow ballast and other tanks. However when the torpedo hit the shears it almost certainly caused severe disruption on the boat. There are a number of ballast tanks that need to be blown IMMEDIATELY and in a particular sequence. There is only one handle that fits onto each of the valves and if that was lost or dropped when the torpedo hit the shears it could have extended the time considerably. With a steep down angle one can reach crush depth very rapidly.
5 There is general agreement that the Grunion ended up pointing in a northerly direction (plus or minus 20 degrees) . For that to happen and to be hit by a circular dud torpedo coming in over the stern the target had to be southerly. (There is a some conflict here because the torpedo shot from the bow. The explanation is that the Grunion was trying to establish adequate distance 800 yds for additional shots). The explanation for the difference between Aiura’s path is that it was difficult to differentiate whether the Kano Maru was moving or the Grunion. See CT’s plot path below.
