Remove ads

Changing Destiny (Kancolle)

Reader mode
Wobulator said:
I couldn't find any hard and fast sources, but they shared many of the same flaws.
Click to expand...
Click to shrink...

The Mark 14 is basically a shorter Mark 15, because it's being fired from the space constraint of a submarine

Gosu said:
25 October 1942 USS Mustin was ordered to scuttle the USS Hornet. She sat a mile off the wreck's beam and deliberately fired eight carefully aimed torpedoes. Not even target practice, so easy.

One Mk15 broached astern of the carrier, another circled but thankfully exploded by itself 300 meter from Mustin, one exploded ... somewhere ..., but not against the carrier, two more just disappeared. Three exploded against Hornet's hull.

This wasn't enough so USS Anderson was called in. Another eight fish were fired, of which one somehow missed the stationary target and one prematured. Six hit, but on the high side so the hulk settled more on an even keel.

BuOrd's reaction was a minor change to the spring in the contact exploder and admonishments to better perform maintenance.
Click to expand...
Click to shrink...

So 3/8 exploded in the first salvo, and six of eight exploded in the second. What was that about a 70% failure rate? Any rate, the failure of the Mark 15s to sink Hornet is due to a combination of her fairly good TDS (rated for around 500 pounds of TNT. Guess what the size of the warhead of a Mark 15 is?), excellent internal compartmentalization, and the location of the hits. A hit that opens already-flooded compartments is not going to do anything to sink a ship.

Let's move on to how the IJN is going to treat the Mark 15. Now, if I'm a skipper of a ship that doesn't have a TDS like, oh, say, a cruiser, I'm not going to call 3/8 or even 3 in 10 a good chance assuming I know that the odds are 3 in 8 instead of 8 in 8. Because again, the IJN believes American torpedoes work. Neither of you have provided any evidence that the enemy knows the fish have problems, which means, as I have said repeatedly, the IJN must treat every Mark 15 as if it is a Long Lance. This is especially true of destroyer and cruiser skippers, because their ships do not have torpedo defense, with the exception of certain IJN CAs, which have TDS rated for roughly 200 pounds of TNT to protect against near-misses. That's not going to suffice against a 484 pound warhead. Now, why does this matter? Because IJN ships cannot maneuver and maintain a solution with their guns, which means that if you force their ships to maneuver, you have bought your ships a few salvos without any return fire.

You seem to be missing something. I am not defending BuOrd. However, you are badly misrepresenting the torpedo, and the threat it presents.

As to the contact exploder... The change needed to fix the damned thing was an alteration to the spring. It needed a heavier spring. And the admonishment to perform better maintenance was because the success rate in use was high enough that it could be treated as evidence that the design of the torpedo was sound, and therefore the problem must be operator error.
 
Last edited:
PAGDTenno said:
3) The problem with the Mark 14 and 15 wasn't that it didn't work, it was that it worked often enough that BuOrd thought the problem was user error, not a problem with the torpedo itself.
Click to expand...
Click to shrink...

Wobulator said:
The contact detonator alone had a 70% failure rate. I couldn't find anything for all the other faults, but I think it's fair to assume that it was pretty awful.
Click to expand...
Click to shrink...
The problem is that those failures were not easy to detect in combat, since the first of the failures of the torpedo had to do with the way it adjusted dept and the steering most naval officers thought they had missed, until a series of incidents, like with the Hornet, make it clear that this was not a matter of aim, but by then there were enough reports about normal ops on the torpeadoes that they dismissed the captain's complains as excuses for either poor performance, poor maitenance or poor aim. Then after that was corrected and the torpeadoes started hitting what they were aiming for the error in the magnetic detonators happened, which meant that the fishes blew up too far from the hull to do catastrofic damage, something that was usually reported as a positive hit, but since in many occasions the sub had to run after the impact they couldn't properly evaluate damage until once more the naval units discovered that thos things were detonating too soon. And when the naval forces were finally allowed to disconnect the magnetic triggers they discovered that the contact detonators were having a problem with their rods that made them fail when hitting a ship directly and were only successful when hitting the hull on an angle.

The history of the torpeados from the perspective of the Navy Bureau of Ordenance is quite interesting, especially this article of Hyperwar.
 
Wobulator said:
...no.
That is definitely not true.
The contact detonator alone had a 70% failure rate. I couldn't find anything for all the other faults, but I think it's fair to assume that it was pretty awful.
Click to expand...
Click to shrink...

IIRC the failure rate for that torpedo family, or at least the Mk 14 submarine torpedo, came out to over 100%, in that they on average had more than one defect that made them more dangerous than strapping stacks of bombs pained with bulls-eyes to your deck.
 
Last edited:
Guardian54 said:
IIRC the failure rate for that torpedo family, or at least the Mk 14 submarine torpedo, came out to over 100%, in that they on average had more than one defect that made them more dangerous than strapping stacks of bombs pained with bulls-eyes to your deck.
Click to expand...
Click to shrink...
Could you stop with the hyperbole? American torpedoes had issues that too often rendered them useless, but going kaboom on deck wasn't one of them. The very stable warhead meant that the worst that could happen was the methanol fuel catching fire.
 
CV12Hornet said:
Could you stop with the hyperbole? American torpedoes had issues that too often rendered them useless, but going kaboom on deck wasn't one of them. The very stable warhead meant that the worst that could happen was the methanol fuel catching fire.
Click to expand...
Click to shrink...

I meant the fuel tanks. In that if hit they could go up.

Because unless you are stacking more bombs than is probably wise (cough the depth charge racks cough), they're generally a smaller target than a 5-tube torpedo turret.

And some types of bombs (depth charges or mines) are more useful than the torpedoes in most applications due to reliability. Hence the danger is better accepted :p

And if the methanol has any time to spread before catching, well... and it's not impossible for detonators to be set off by explosions stoving the contact pistol in.
 
Last edited:
If the fuel goes up, the fire will most certainly set the warheads of the torpedoes off. Methanol burns at over a thousand degrees, even with how stable TNT and Torpex is, it would be heated fairly quickly to the point where the stuff would just explode on it's own.
 
Guardian54 said:
I meant the fuel tanks. In that if hit they could go up.

Because unless you are stacking more bombs than is probably wise (cough the depth charge racks cough), they're generally a smaller target than a 5-tube torpedo turret.

And some types of bombs (depth charges or mines) are more useful than the torpedoes in most applications due to reliability. Hence the danger is better accepted :p

And if the methanol has any time to spread before catching, well... and it's not impossible for detonators to be set off by explosions stoving the contact pistol in.
Click to expand...
Click to shrink...

I don't think you realize quite how paranoid the safeties on US detonators are. "Not impossible" is an accurate assessment, but the sequence of events required to arm the contact pistol requires the impeller to rotate a certain number of times (which when the fish is in the water, means traveling a certain distance) before a sufficient impact hits the contact detonator. Before the impeller rotates, the pistol is not armed, and a 3000 pound battleship shell striking the contact pistol will not cause it to detonate. For all practical purposes, one might as well call it "impossible."

As to the fuel... shrug. Price of doing business if you want any kind of decent range.

Thorthemighty said:
If the fuel goes up, the fire will most certainly set the warheads of the torpedoes off. Methanol burns at over a thousand degrees, even with how stable TNT and Torpex is, it would be heated fairly quickly to the point where the stuff would just explode on it's own.
Click to expand...
Click to shrink...

You can burn TNT and TPX and they won't explode. They require heat and a shockwave to go off. In fact, TNT will boil if you throw it into a methanol fire (boiling point of TNT is 464 degrees Fahrenheit, and when it boils it also decomposes, meaning it is no longer an explosive). The warheads are a nonissue.
 
PAGDTenno said:
You can burn TNT and TPX and they won't explode. They require heat and a shockwave to go off. In fact, TNT will boil if you throw it into a methanol fire (boiling point of TNT is 464 degrees Fahrenheit, and when it boils it also decomposes, meaning it is no longer an explosive). The warheads are a nonissue.
Click to expand...
Click to shrink...

Damn, that's pretty stable stuff. Although with the Methanol, I have a feeling that if that stuff goes up, you might get a Boiling Liquid Expanding Vapor Explosion or BLEVE for short. That will probably do major damage, not as much as a Type-93 detonating on the deck, but still substantial.
 
I don't think there's a single incident on a US submarine (that I know of) where a torpedo exploded aboard the ship. I don't think I've heard of it happening on any USN Surface ships either.
 
PAGDTenno said:
So 3/8 exploded in the first salvo, and six of eight exploded in the second. What was that about a 70% failure rate? Any rate, the failure of the Mark 15s to sink Hornet is due to a combination of her fairly good TDS (rated for around 500 pounds of TNT. Guess what the size of the warhead of a Mark 15 is?), excellent internal compartmentalization, and the location of the hits. A hit that opens already-flooded compartments is not going to do anything to sink a ship.
Click to expand...
Click to shrink...
I wasn't the one who mentioned a 70% failure rate so I don't feel any need to prove it.

Hornet was hit by three Japanese airplane and eight American torpedoes (and a number of Long Lance when the Japanese scuttled her). Here is the damage report on the damage from the Japanese airplane torpedoes:

21. From the references it is estimated that this torpedo struck about frame 110-1/2 starboard on the armor belt, about 6-1/2 feet below the waterline. As is usual with torpedo hits in the middle body no appreciable shock damage resulted. The torpedo defense system in way of the engine rooms is a four-bulkhead system. The outboard layer of tanks was filled with liquid in accordance with the latest liquid loading practice as recommended by the Bureau. Fuel oil service tanks in the second and third layers were filled (see Plate IV). From a study of previous damage to this type of system by Japanese aircraft torpedoes, it is quite probable that the outboard row of tanks from frame 99 to frame 123, the second row of tanks from frames 101 to 123, the third row from frames 103 to 118, and the fourth row from frames 106 to 120, were ruptured and in free communication with the sea. Undoubtedly the shell plating, No. 1 and No. 2 bulkheads were destroyed in way of the explosion and one or more plates of 4-inch special treatment steel armor blown off; No. 3 bulkhead was dished and holed; and No. 4, the holding bulkhead, was ruptured between frames 110 and 112. An eyewitness estimates that the hole was 5-6 feet long and 3-4 feet high. Probably the after starboard corner of No. 9 boiler room was weakened or damaged by the torpedo explosion, as this compartment is reported to have partially flooded. Probably the 60 lb. special treatment steel deck in the crew's space, C-403-L, was ruptured and blown upwards by the force of the explosion. The 25 lb. special treatment steel inboard bulkhead of this compartment must have remained intact inasmuch as no flooding was reported into the aviation storeroom, C-402-A.

22. The Chief Engineer, in reference (a), reported that in the after engine room No. 2 main condenser had "collapsed internally" and the turbines filled with salt water. He also reported that No. 3 unit had lost vacuum apparently due to condenser damage. It is not clear how "internal collapse" could take place as the shock does not appear to have been unusually severe and no other machinery derangements were reported. It is possible, however, that some tubes could have been jarred sufficiently to cause leakage through the tube sheet and from there to the turbines. This is the first such case noted of internal damage to condensers resulting from torpedoes. Main and auxiliary steam lines remained intact as were feed lines, fuel oil lines, port service tanks and fuel oil transfer pump.
Click to expand...
Click to shrink...

23. This torpedo, which struck about 20 seconds after torpedo "E", is reported to have struck the starboard side about frame 160, probably on the armor belt about six feet below the waterline. Apparently there was very little shock. The hole blown in the ship's side was reported to be about 30 feet long and 15 feet deep, of which some of the damaged area was above the waterline. The torpedo defense system in way of the hit is a four-bulkhead system which ends just eight feet abaft the estimated point of impact. The starboard fuel oil tanks and damage control voids aft of frame 150 were probably ruptured. Undoubtedly the four-inch special treatment steel armored bulkhead at frame 162 was disrupted or deflected aft sufficiently to cause leakage at the junction of this bulkhead with the holding bulkhead. As stated in paragraph 17, this torpedo struck about two minutes after the bomb hit at frame 155, making it extremely difficult to determine which explosion was the cause of the damage on the third and fourth decks. It is quite probable, however, that most of the third deck was damaged by the bomb detonation, whereas the damage to the fourth deck in D-415-L and D-417-A was a result of the torpedo. Although damage to the fourth deck in this vicinity was not reported, it must have been extensive because the shell above the fourth deck was ruptured for a distance of about 30 feet. Bulkhead 165 was ruptured by either the bomb or torpedo explosion as flooding was reported in D-419-A.

24. The No. 2 (inboard starboard) shaft alignment must have been disturbed by this torpedo detonation as its bearings ran quite hot (180° F; for the short time that it continued to rotate after the torpedo hit. The rudder was reported jammed 30° left as a result of this hit..
Click to expand...
Click to shrink...

44. The aircraft torpedo which hit at frame 115 on the starboard side was also a shallow-running torpedo. It hit just aft and above torpedo hit "E". Since the ship was listing 7° to starboard, the torpedo probably hit just above the armor belt, the top of which is in line with the fourth deck. Survivors on the third deck reported a sickly green "flash".

45. It is definitely known that the forward bulkhead of the after engine room was ruptured. Both feed water heaters in the after engine room were knocked over. The port side of the third deck was cracked open in way of the crew's mess room, C-301-1L. Apparently damage resulted to the after generator room; however, it is doubtful that this space flooded except through damaged piping or leaky cable stuffing boxes. The damage enumerated above resulted in the immediate flooding of the after engine room and the fourth deck in way of the explosion. Although not reported, undoubtedly crew space C-409-L and refrigerating compartments C-408-1A to C-408-8A on the fourth deck were flooded. An electrical cable in D-301-1LM was severed and a fire was started which was quickly extinguished by Repair V personnel.
Click to expand...
Click to shrink...

The USN should be somewhat surprised I think that where three airplane torpedoes did a lot of damage through the TDS, no less than 8 of their own destroyer torpedoes were that much less effective in scuttling the ship, TDS or not. I think it unlikely that the Americans considered their destroyer torpedoes that much less powerful than Japanese airplane torpedoes.

PAGDTenno said:
Let's move on to how the IJN is going to treat the Mark 15. Now, if I'm a skipper of a ship that doesn't have a TDS like, oh, say, a cruiser, I'm not going to call 3/8 or even 3 in 10 a good chance assuming I know that the odds are 3 in 8 instead of 8 in 8. Because again, the IJN believes American torpedoes work. Neither of you have provided any evidence that the enemy knows the fish have problems, which means, as I have said repeatedly, the IJN must treat every Mark 15 as if it is a Long Lance. This is especially true of destroyer and cruiser skippers, because their ships do not have torpedo defense, with the exception of certain IJN CAs, which have TDS rated for roughly 200 pounds of TNT to protect against near-misses. That's not going to suffice against a 484 pound warhead. Now, why does this matter? Because IJN ships cannot maneuver and maintain a solution with their guns, which means that if you force their ships to maneuver, you have bought your ships a few salvos without any return fire

You seem to be missing something. I am not defending BuOrd. However, you are badly misrepresenting the torpedo, and the threat it presents..
Click to expand...
Click to shrink...
Well, two different things here. If it's a day gun fight, then Japanese doctrine is to outrange the enemy, and that means they will be out of effective range of US torpedoes (like at the Java Sea and Kommandorski battles). If it's a night fight at closer ranges, they are less likely to see the incoming torpedoes timely. So yes, while in theory the Japanese must treat each torpedo as dangerous, by their doctrine the only time when they would be in range of those torpedoes would also be when they can't reliably spot incoming torpedoes at a distance.

PAGDTenno said:
As to the contact exploder... The change needed to fix the damned thing was an alteration to the spring. It needed a heavier spring. And the admonishment to perform better maintenance was because the success rate in use was high enough that it could be treated as evidence that the design of the torpedo was sound, and therefore the problem must be operator error.
Click to expand...
Click to shrink...
The Hornet fiasco caused a lot of consternation among US admirals, and it was argued that this many failures (including prematures and circular runs) could not all be attributed to bad maintenance and light springs. Which they were right about.
 
Last edited:
Gosu said:
The USN should be somewhat surprised I think that where three airplane torpedoes did a lot of damage through the TDS, no less than 8 of their own destroyer torpedoes were that much less effective in scuttling the ship, TDS or not. I think it unlikely that the Americans considered their destroyer torpedoes that much less powerful than Japanese airplane torpedoes.
Click to expand...
Click to shrink...

Well, they were wrong. The Type 91 had a 713 pound warhead(770 pounds TNT equivalent, using postwar test results of Type 98 being 1.08 times as destructive as TNT), which is substantially larger than the 494 pound TNT warhead the Mark 15 mounted.

Gosu said:
Well, two different things here. If it's a day gun fight, then Japanese doctrine is to outrange the enemy, and that means they will be out of effective range of US torpedoes (like at the Java Sea and Kommandorski battles). If it's a night fight at closer ranges, they are less likely to see the incoming torpedoes timely. So yes, while in theory the Japanese must treat each torpedo as dangerous, by their doctrine the only time when they would be in range of those torpedoes would also be when they can't reliably spot incoming torpedoes at a distance.
Click to expand...
Click to shrink...

There is no range where the IJN can shoot at US cruisers and the US cruisers cannot shoot back. And in fact, at Kommandorski a torpedo attack was considered a realistic possibility for the escorting destroyers, and was ordered multiple times, only to be called off for the destroyers to maintain a smoke screen on Salt Lake City, though Bailey successfully launched a five-torpedo salvo at 9500 yards after she and two of her sisters were finally able to press the attack. The salvo missed.
 
PAGDTenno said:
Well, they were wrong. The Type 91 had a 713 pound warhead(770 pounds TNT equivalent, using postwar test results of Type 98 being 1.08 times as destructive as TNT), which is substantially larger than the 494 pound TNT warhead the Mark 15 mounted.
Click to expand...
Click to shrink...
What is your source that she was hit by the brand new mod 3 version? The mod 2 version with 450 pound explosive was still less than a year old.

You're comparing Japanese warhead weight and US explosive filler weight. The weight of the explosive filler in the Type 91 mod 3 warhead was 530 pounds, which while more, is not 155% more than the US warhead. See the table on page 11.

Also, the US Navy would not know this, so how exactly can it factor in their deliberations?

PAGDTenno said:
There is no range where the IJN can shoot at US cruisers and the US cruisers cannot shoot back. And in fact, at Kommandorski a torpedo attack was considered a realistic possibility for the escorting destroyers, and was ordered multiple times, only to be called off for the destroyers to maintain a smoke screen on Salt Lake City, though Bailey successfully launched a five-torpedo salvo at 9500 yards after she and two of her sisters were finally able to press the attack. The salvo missed.
Click to expand...
Click to shrink...
True. But, it didn't just miss, it appears the Japanese didn't even know torpedoes had been fired. As an example of how US torpedoes can force the Japanese to act, it falls a bit flat.

Edit: the Japanese disengaged just before or exactly when as the torpedoes were fired because of expected air attack, low ammunition, and high fuel use.
 
Last edited:
While the argument seems to have died on its own, let's try to keep things more on track from now on.

Or I'll have to start deploying the derail pics again.

 
Guardian54 said:
I regret to inform you that THIS is what a real derail boat/ship looks like, not... that.
Train ferry - Wikipedia
Click to expand...
Click to shrink...

Actually...

There ARE some rail connections at the Navy Yards. Brooklyn Eastern District Terminal , BEDT , East River Terminal Railroad & Palmers Dock



Thompson would be astounded at the waterfront activity in NY Harbor, which was full of ferries and car floats at this time.

Comprehensive List of Transfer / Float Bridges for New York Harbor
 
Well, in an effort to get the thread back on track (rail or otherwise), here's a subject for discussion.

Can Wake Island be saved at this point?

Even if Hiryu and Kaga are sunk ala Midway, there are still Japanese troops landed with offshore fire support from the CA/CL/DDs. Historically the Wake Island garrison was 449 men compared to the 2500 Japanese troops in the second (successful) invasion attempt which is currently in progress. In addition, two major things mitigate against USN disruption of the landings in progress.

First, the main effort of Sara and E have to be against the IJN carriers unless they plan to wind up in the same boat the Kido Butai were at Midway (striking the area near the island with hostile carriers present). This means that any action against the transports/landing force will be delayed several hours since airstrikes will have to be launched against carriers, recovered, and refueled/rearmed for second strikes. Since there is a limited amount of daylight and the first strike cannot be launched until the IJN carriers are located (or a Japanese strike is spotted coming in), this argues against an early airstrike on the invasion force.

Second, since we are well off the rails of OTL now that a carrier battle is breaking out at Wake, Thompson has to assume that the other four fleet carriers of the Kido Butai might be called in as reinforcements. Certainly having them arrive from the north/northeast to participate in the fight would be very very dangerous, and the same logic that dictates IJN carrier losses being catastrophic (can't replace them in time to make a difference) also means that USN carrier losses would be damaging at this stage in the war (any sunk fleet carriers will only be replaced in late 1942/early 1943 with the Essexes and will keep the USN on the back foot similar to OTL). Therefore, the orders for this operation are probably "get in, reinforce Wake, do what damage you can to the invasion and get out". Hanging around the scene of the crime to shoot up the transports/shore bombardment force will be very very risky, much less land needed reinforcements.

Finally, in the cold calculus of wartime, losing Wake is a blow, but not a fatal blow (see OTL), and exchanging Wake for one or more IJN carriers sunk or crippled is a major positive outcome for the USN, since that loss will constrain Japanese strategic options in the 6-12 month window they have to do something before growing USN strength slams said window shut.
 
SisterJeanne said:
Well, in an effort to get the thread back on track (rail or otherwise), here's a subject for discussion.

Can Wake Island be saved at this point?

Even if Hiryu and Kaga are sunk ala Midway, there are still Japanese troops landed with offshore fire support from the CA/CL/DDs. Historically the Wake Island garrison was 449 men compared to the 2500 Japanese troops in the second (successful) invasion attempt which is currently in progress. In addition, two major things mitigate against USN disruption of the landings in progress.

First, the main effort of Sara and E have to be against the IJN carriers unless they plan to wind up in the same boat the Kido Butai were at Midway (striking the area near the island with hostile carriers present). This means that any action against the transports/landing force will be delayed several hours since airstrikes will have to be launched against carriers, recovered, and refueled/rearmed for second strikes. Since there is a limited amount of daylight and the first strike cannot be launched until the IJN carriers are located (or a Japanese strike is spotted coming in), this argues against an early airstrike on the invasion force.

Second, since we are well off the rails of OTL now that a carrier battle is breaking out at Wake, Thompson has to assume that the other four fleet carriers of the Kido Butai might be called in as reinforcements. Certainly having them arrive from the north/northeast to participate in the fight would be very very dangerous, and the same logic that dictates IJN carrier losses being catastrophic (can't replace them in time to make a difference) also means that USN carrier losses would be damaging at this stage in the war (any sunk fleet carriers will only be replaced in late 1942/early 1943 with the Essexes and will keep the USN on the back foot similar to OTL). Therefore, the orders for this operation are probably "get in, reinforce Wake, do what damage you can to the invasion and get out". Hanging around the scene of the crime to shoot up the transports/shore bombardment force will be very very risky, much less land needed reinforcements.

Finally, in the cold calculus of wartime, losing Wake is a blow, but not a fatal blow (see OTL), and exchanging Wake for one or more IJN carriers sunk or crippled is a major positive outcome for the USN, since that loss will constrain Japanese strategic options in the 6-12 month window they have to do something before growing USN strength slams said window shut.
Click to expand...
Click to shrink...
That, and it'd be nice to see the start of Lil E's growth/legend from being, "I'll do my best!", fresh faced & untested young girl/carrier, to the, "Ow, stupid kamikaze blew my elevator 600 ft straight up. Meh. Just another ding.", cool as a cucumber veteran post-Battle of Santa Cruz who's prowess as a carrier has yet to be equalled.
 
Last edited:
Reader mode
You must login or register to reply here.
Remove ads
Back
Top