USS Tautog ambushes Pearl Strike Force

Further notes and observations after reading the last several posts:

ThreeDee, why did you pick Tautog for this scenario? On 07 December, Tautog was in port at Pearl undergoing refit. In the OTL she did not get underway until the day after Christmas. Unless you chose Tautog for a specific reason, it may make more sense to have one of the boats that was already at sea to intercept the retreating Japanese. Sister boat Trout and the big old Argonaut were off Midway, with Tambor and Triton patrolling north of Wake. One of these boats would probably be more likely to intercept Kido Butai than the Tautog, which probably wouldn't have been able to get underway for several days at best.

Radio reception for low frequency (LF) was possible at periscope depth using a loop antenna. No part of the boat needed to be above the water, indeed the loop antenna itself was usually 10-15 feet under the water at PD. Transmission or HF comms was a bit trickier, requiring a whip style antenna to be above the water. There were a few different types of these antennas with one type attached to the periscope. The height of the antenna above the water determined the range of transmission, with very long range requiring the boat to be surfaced. Assuming your boat is relatively near Hawaii, a contact report could be sent with the boat broached (i.e. only partially surfaced).

As to the chances of sinking a carrier, refer to my post above. There are a lot of variables to consider and the idea is at least possible. They would have to be in a favorable position close to the enemy track and ahead of them, and they would have to get through the destroyer screen without being detected (probability low to medium). At this point approved tactics dictated that they dive to at least 100 feet (they are most likely already there) and track the target on sonar alone. Optimum position for firing would be (obviously) ahead of the target and between 1000-2000 yards off the target track (projected course). Once satisfied with the firing solution they would set the running depth of the torpedoes to approximately 30 feet so that they will run under the keel (the optimum spot for the Mk 6 magnetic influence exploder to detonate the warhead) and fire off a full spread of six torpedoes. They would then go deep (250 feet), rig for silent running, and wait to hear the detonation of the weapons, all the while expecting a depth charge attack from the escorts. But given the conditions that existed within the submarine force at that time, I believe the likelihood of this type of attack being successful to be quite low. During the war, this type of approach was used 31 times with no known successes. Sonar bearings were just not accurate enough and range was nothing but an educated guess. Both of these elements are EXTREMELY important to accurately aiming torpedoes. Sonar was very useful in the initial detection of the target and detection ranges out to 15,000 yards were possible under good conditions. But the very fine and accurate tracking necessary to aim torpedoes was just beyond the capability of the relatively primitive systems of the day.

If Joe Willingham made the unlikely decision to toss out the rule book and make a daylight periscope approach, the likelihood of success goes up considerably, from less than 5% to about 10-30%. Uncertainty and hesitation were quite prevalent and caution was the mantra of operations in the first few months of the war. It would have taken a truly gutsy skipper to go against everything he had been taught was right and to toss out all the experience he had (even as flawed as it later turned out to be) at this stage. Indeed most of the reports of the first submarine actions amply demonstrate this unfortunate mindset. It took time to build up the experience and confidence necessary to take greater chances.

The Mk 14 was actually a very well made, precision-crafted piece of machinery. But the damn thing was full of bugs and faults due to a stunted R&D phase and the overconfident intransigence of the managing engineers at the Bureau of Ordnance. It ran too deep due to the problems I outlined above and this prevented the Mk 6 magnetic exploder from firing when it should. When this fault was discovered, the crews simply set it to run shallower, but then discovered that the MK 6 exploder was so sensitive it set off the warhead prematurely, before it even reached the target! So then they just deactivated the magnetic feature and set the weapon to impact the side of the target using the regular contact exploder. But due to a fault with the firing pin, the damn thing wouldn't go off and it bounced off the side of the ship! The BuOrd managers steadfastly refused to admit that anything was mechanically wrong with the torpedo, blaming all the troubles on the boat crews. Only after field tests and trouble shooting in theater revealed and corrected the problems, and only after being ordered by higher authority to pull their collective heads out of their arses did BuOrd finally get onboard and fix the issues at the factory. When combined with unrealistic pre-war training and poorly thought out tactics the torpedo problems reduced the submarine force to frustrating near impotency.

These issues are why I believe that the chances of getting in a successful attack on one of the Kido Butai carriers at this time to be very low.

As for how this scenario would effect other battles, I just couldn't say for sure. Lots of butterflies there.

The Tautog is there because of butterflies from a TL running in the background that puts it exercising NW of Pearl on the 7th. CAPT Charles Lockwood is onboard the Tautog observing the exercises (this is important because he is getting firsthand experience of the failures of their tactics and torpedoes).

So the scenario seems to be improbable on multiple levels, and I don't think I will be using it in my TL. My goal with this event was twofold; to through a series of high profile events make the higher ups in the Navy realize and take action about the faulty Mk 14 torpedo and submarine tactics, and to make the Japanese fleet seem vulnerable to submarine attack.

I thought of an alternative scenario that seems from what you've said more probable.

The attack begins, and the Tautog receives word almost immediately. It makes all haste East (instead of NE as in the original post). It estimates the fleet's location using the attacking aircraft's bearings and encounters the fleet due East just as they're leaving northward. Willingham prioritizes alerting Pearl of the fleet's location, bearing, and speed over using the "proper" tactics, and stays at periscope depth, firing simultaneously. From periscope depth, they are able to effectively aim and get off a good shot. The message is sent and received, and the Tautog begins an emergency dive to escape their ASW measures. There are four premature detonations and two hits, with both failing to detonate. The Tautog launches its aft torpedoes from the "proper" depth and miss horribly. They stalk the fleet for as long as possible, but they are vastly slower, and quickly fall out of range. The US fleet tries to intercept them with this information, but are unable to.

This still accomplishes my goals and does not cancel the invasion of Wake (which is the next important event).

Does this seem more probable?
 
There are four premature detonations and two hits, with both failing to detonate.

Does this seem more probable?

I truly don't mean to sound harsh, but I don't think you fully understand the problem with the Mk 14 torpedo, or how it was intended to be employed early in the war.

The Mk 14 was fitted with the Mk 6 magnetic influence exploder. This exploder worked by sensing the magnetic field given off by the steel hull of the ship. It was kind of like putting a magnet on a table top and watching it move when you put another magnet near it. The weapon did not need to strike the ship! Since water is incompressible the optimum place for the weapon to detonate is under the ship. The force of the explosion and the bubble is creates would (in theory) break the back of the ship. This was desirable because fewer torpedoes needed to be used to sink a ship.

So, to get the exploder to work the way it was intended, the Mk 14 was deliberately set to run under the target, "missing" by a few feet, with the exploder tripping and firing the warhead as it passed under the keel. To give the submarine commanders an option, the Mk 6 also had a backup contact exploder mechanism, which if the captain desired could be used in a more standard type attack by setting the torpedo to run at a depth which would cause it to strike the ship, firing the exploder and warhead in the traditional fashion. In order to use this option, the magnetic feature had to be disabled by the submarine's crew prior to firing. Because of the desire to make the submarines effective as possible, the captains were under very strict orders to always use the magnetic feature. Indeed, disabling it was cause for severe reprimand.

As stated before, the Mk 14's depth keeping system was flawed and it caused the weapon to run 10-13 feet deeper than set. This caused to weapon to run so deep that the Mk 6 could not sense the magnetic field of the ship and the weapon passed under the target harmlessly. Once it was understood that this was happening, the crew simply began to set the weapon to run shallow, thinking that they had solved the problem.

Then they ran into problem number 2: prematures. The few tests of the Mk 14 that were done were all completed on the U.S. east coast. In this area of the planet a ship's magnetic field took on the shape of a half-cylinder, projecting in a fairly uniform shape out from the sides and wrapping around and under the hull. Imagine taking a pipe, cutting it in half lengthwise, and placing the ship in it with the upper edges of the half pipe roughly corresponding to the waterline. Setting the weapon to run deep enough to pass just under the keel, the Mk 6 would intersect the field directly under the keel and detonate the warhead. Perfect! The problem is that a ship's magnetic field is not uniform in shape everywhere in the world. The shape will vary greatly depending on where it is because the earth's mag field isn't uniform either. This was not fully understood when the weapon was being developed and the designers made an unfortunate assumption. In the Pacific, especially the western Pacific, a ship's field tended to flatten out, bulging out at the sides and being very close to the keel underneath. Therefore if you set the weapon to run shallow it would tend to intersect the target's mag field some distance away from the hull and the warhead would fire too soon!

Once they realized this, they said to hell with the magnetic feature, disabled it, and set the weapon to impact the ship with the intention of using the contact feature. They then ran into problem number 3: duds. The firing pin for the contact portion was set in the exploder at a right angle (perpendicular) to the axis of the weapon. When the weapon struck the side of the ship, the inertia of the heavy pin forced it against the firing pin housing, preventing it from traveling far enough to set off the warhead! It took a series of tests of the mechanism on dry land to figure out what the hell was going on. The solution ended up being quite simple: make a firing pin out of a lighter weight material so it had less inertia.

I have explained all of this to point out several key points of your scenario. First, Willingham most probably would NOT have gotten "hits" with detonations using the Mk 14 with the mag exploder feature enabled, and this is what he was under strict orders to do! Second, even if you have him willingly disobey orders (I strongly doubt that he would have at this point in the war, mostly because he had no reason to) and DID disable the mag feature and set the torps to hit, it is likely the torps would have been duds! It is even less likely he would have done this with a high ranking officer on board watching him! By the way, Charlie Lockwood was in London at the start of the war as a Naval Attache, and was no where near Hawaii.

The really stupid thing was that under certain narrow (and inconsistent) circumstances, the damnable Mk 14 WOULD work the way it was supposed to and you would get detonations and contact hits, but the percentage remained extremely low. This caused everyone to second guess themselves and delayed the overall effort to fix it and make it run right.

If you want consistent hits early in the war, you have to come up with a POD which butterflies away the torpedo problems. I started a thread several years ago on this very thing: https://www.alternatehistory.com/forum/threads/the-great-torpedo-scandal-avoided.109950/.
 
Last edited:
If you cant realistically get a kill with the Mk14 what about the posthumous MoH way, AKA HMS Glowworm style?
They just mess up the attack on a CV target and USS Tautog hits a glancing blow to the side of one of the oncoming IJN CVs in the other column, ripping USS Tautog apart but also ripping a tear down one side of the carrier breaching far to much of its side protection followed by a rapid capsize. Nobody in US finds out about it till interviewing IJN personnel post war in 45 when they finally work out why the IJN lost one of its carriers...
 
Wow do I feel stupid. The sad thing is that I knew all of these things, but just somehow didn't connect the dots that the Mark 14 was actually set to run low and not to hit the ship. I guess it still works if you replace "hits" with "properly positioned to where the detonator should ideally detonate".

I had been under the impression though that even when set to "normal" depth (actually running deep) that subs early in the war still experienced significant numbers of premature detonations in the Pacific, but I could be wrong.

CAPT Lockwood is still in Pearl Harbor as Chief of Staff to COMSUBPAC because of the TL.

But, do you think this scenario is more realistic? I think them encountering before the fleet leaves makes it more likely for them to find the Kido Butai. Also if they only have a short window to fire on the fleet, I don't think they would waste time sinking to depth when they might not get the chance to launch, and I think getting the radio message out is much more important than firing the torpedoes.
 
Last edited:
and I think getting the radio message out is much more important than firing the torpedoes.
Why if the KB is leaving the area for Japan as OTL what can a radio message do for USN? Can anything else theoretically intercept the force in time?
 
I truly don't mean to sound harsh, but I don't think you fully understand the problem with the Mk 14 torpedo, or how it was intended to be employed early in the war.

The Mk 14 was fitted with the Mk 6 magnetic influence exploder. This exploder worked by sensing the magnetic field given off by the steel hull of the ship. It was kind of like putting a magnet on a table top and watching it move when you put another magnet near it. The weapon did not need to strike the ship! Since water is incompressible the optimum place for the weapon to detonate is under the ship. The force of the explosion and the bubble is creates would (in theory) break the back of the ship. This was desirable because fewer torpedoes needed to be used to sink a ship.

So, to get the exploder to work the way it was intended, the Mk 14 was deliberately set to run under the target, "missing" by a few feet, with the exploder tripping and firing the warhead as it passed under the keel. To give the submarine commanders an option, the Mk 6 also had a backup contact exploder mechanism, which if the captain desired could be used in a more standard type attack by setting the torpedo to run at a depth which would cause it to strike the ship, firing the exploder and warhead in the traditional fashion. In order to use this option, the magnetic feature had to be disabled by the submarine's crew prior to firing. Because of the desire to make the submarines effective as possible, the captains were under very strict orders to always use the magnetic feature. Indeed, disabling it was cause for severe reprimand.

As stated before, the Mk 14's depth keeping system was flawed and it caused the weapon to run 10-13 feet deeper than set. This caused to weapon to run so deep that the Mk 6 could not sense the magnetic field of the ship and the weapon passed under the target harmlessly. Once it was understood that this was happening, the crew simply began to set the weapon to run shallow, thinking that they had solved the problem.

Then they ran into problem number 2: prematures. The few tests of the Mk 14 that were done were all completed on the U.S. east coast. In this area of the planet a ship's magnetic field took on the shape of a half-cylinder, projecting in a fairly uniform shape out from the sides and wrapping around and under the hull. Imagine taking a pipe, cutting it in half lengthwise, and placing the ship in it with the upper edges of the half pipe roughly corresponding to the waterline. Setting the weapon to run deep enough to pass just under the keel, the Mk 6 would intersect the field directly under the keel and detonate the warhead. Perfect! The problem is that a ship's magnetic field is not uniform in shape everywhere in the world. The shape will vary greatly depending on where it is because the earth's mag field is uniform either. This was not fully understood when the weapon was being developed and the designers made an unfortunate assumption. In the Pacific, especially the western Pacific, a ship's field tended to flatten out, bulging out at the sides and being very close to the keel underneath. Therefore if you set the weapon to run shallow it would tend to intersect the target's mag field some distance away from the hull and the warhead would fire too soon!

Once they realized this, they said to hell with the magnetic feature, disabled it, and set the weapon to impact the ship with the intention of using the contact feature. They then ran into problem number 3: duds. The firing pin for the contact portion was set in the exploder at a right angle (perpendicular) to the axis of the weapon. When the weapon struck the side of the ship, the inertia of the heavy pin forced it against the firing pin housing, preventing it from traveling far enough to set off the warhead! It took a series of tests of the mechanism on dry land to figure out what the hell was going on. The solution ended up being quite simple: make a firing pin out of a lighter weight material so it had less inertia.

I have explained all of this to point out several key points of your scenario. First, Willingham most probably would NOT have gotten "hits" with detonations using the Mk 14 with the mag exploder feature enabled, and this is what he was under strict orders to do! Second, even if you have him willingly disobey orders (I strongly doubt that he would have at this point in the war, mostly because he had no reason to) and DID disable the mag feature and set the torps to hit, it is likely the torps would have been duds! It is even less likely he would have done this with a high ranking officer on board watching him! By the way, Charlie Lockwood was in London at the start of the war as a Naval Attache, and was no where near Hawaii.

The really stupid thing was that under certain narrow (and inconsistent) circumstances, the damnable Mk 14 WOULD work the way it was supposed to and you would get detonations and contact hits, but the percentage remained extremely low. This caused everyone to second guess themselves and delayed the overall effort to fix it and make it run right.

If you want consistent hits early in the war, you have to come up with a POD which butterflies away the torpedo problems. I started a thread several years ago on this very thing: https://www.alternatehistory.com/forum/threads/the-great-torpedo-scandal-avoided.109950/.

I love this site - I now release that while I understood the Mk14s had issues I was not aware of what they were - I always understood it to be the contact exploder and not a magnetic influence type trigger

So thank you very much for explaining it for us along with the tactics of the day

Torpedoes are an interesting weapon - probably one of the most complex weapon systems - certainly of the early stage of the war - and to think 2 years later the US deployed an anti submarine homing torpedo that had a staggeringly successful hit rate of 25% when used in action (37 sinkings and 18 damaged U-boats out of 204 weapons used)
 
The really stupid thing was that under certain narrow (and inconsistent) circumstances, the damnable Mk 14 WOULD work the way it was supposed to and you would get detonations and contact hits, but the percentage remained extremely low. This caused everyone to second guess themselves and delayed the overall effort to fix it and make it run right.

Forgive the self-quote, but I feel this is important.

As I said above, the problems with the Mk 14 were at times frustratingly inconsistent. For instance, a ship's mag field may change in shape a little depending on what course it is steering, and even based upon the configuration of the ship itself. As an example, a ship steering a westerly course in Asiatic waters may have a very flat horizontal donut shape field. Change course 90 degrees and the shape may alter enough to actually detonate the exploder as it runs under the keel. Also, the Soryu may have a slightly different shape to its mag field as compared to the Akagi, due to the different designs of the ships.

It was also shown that the contact exploder was slightly more effective if the weapon struck the hull at an oblique angle, as opposed to the desired perpendicular 90 degree angle. In other words the better you set up the target the less chance you had of the weapon going off!

Statistics also showed that the more aggressive skippers (like Morton on Wahoo) tended to get more sinkings despite having the same torpedo problems. This was because they relentlessly drilled and trained their crews, they studied the shipping lanes and put themselves into a position necessary to find targets, they closed the target to nearly point blank range to ensure hits, and they fired a lot of torpedoes with the idea that the more you shoot the better your chances.

All of this tended to mask and obscure the problems with the Mk 14 and made finding and fixing the problems difficult and time consuming. On the first day of the war, none of this was known yet to the submarine force.

When studying history it is dangerous to speak in absolutes, so notice how many times in the last few posts that I said "may", "at times", "probably", etc. That is a way of accounting for variables like I just described. So, with all that said, could your scenario work? Yes... it is possible. But the probability is just very very low.
 
Forgive the self-quote, but I feel this is important.

As I said above, the problems with the Mk 14 were at times frustratingly inconsistent. For instance, a ship's mag field may change in shape a little depending on what course it is steering, and even based upon the configuration of the ship itself. As an example, a ship steering a westerly course in Asiatic waters may have a very flat horizontal donut shape field. Change course 90 degrees and the shape may alter enough to actually detonate the exploder as it runs under the keel. Also, the Soryu may have a slightly different shape to its mag field as compared to the Akagi, due to the different designs of the ships.

It was also shown that the contact exploder was slightly more effective if the weapon struck the hull at an oblique angle, as opposed to the desired perpendicular 90 degree angle. In other words the better you set up the target the less chance you had of the weapon going off!

Statistics also showed that the more aggressive skippers (like Morton on Wahoo) tended to get more sinkings despite having the same torpedo problems. This was because they relentlessly drilled and trained their crews, they studied the shipping lanes and put themselves into a position necessary to find targets, they closed the target to nearly point blank range to ensure hits, and they fired a lot of torpedoes with the idea that the more you shoot the better your chances.

All of this tended to mask and obscure the problems with the Mk 14 and made finding and fixing the problems difficult and time consuming. On the first day of the war, none of this was known yet to the submarine force.

When studying history it is dangerous to speak in absolutes, so notice how many times in the last few posts that I said "may", "at times", "probably", etc. That is a way of accounting for variables like I just described. So, with all that said, could your scenario work? Yes... it is possible. But the probability is just very very low.

I recall reading that the firing pin of the Mk14 was relatively fragile and it broke if it hit a target at a direct angle, while did not break at an oblique angle. Its been a few years since I read that so I don't recall the source. I remember reading that a stronger firing pin was the fix for that.
 
I recall reading that the firing pin of the Mk14 was relatively fragile and it broke if it hit a target at a direct angle, while did not break at an oblique angle. Its been a few years since I read that so I don't recall the source. I remember reading that a stronger firing pin was the fix for that.

Unfortunately that is not correct. It was exactly the opposite problem with the opposite fix, as I described. Fun fact: the first of the lighter firing pins were machined out of aluminum propeller blades recovered from Japanese planes shot down at Pearl Harbor.
 
Unfortunately that is not correct. It was exactly the opposite problem with the opposite fix, as I described. Fun fact: the first of the lighter firing pins were machined out of aluminum propeller blades recovered from Japanese planes shot down at Pearl Harbor.

like I said its been a while, but that the firing pin was the problem was what I remembered

Nice on the recycling

Its been years since I read "US Submarine Operations in World War II" (decades in fact) while even my last read of "Silent Victory" was a decade ago

Both are excellent as I recall
 
And who doesn't fondly remember "The Silent Service " TV show from the late '50s. Before Spock was a science officer, he was a sonar operator.
 
Top