Question on japanese torpedoes....

[Krusty]

Saw on "Battlefield commanders" today something about Midway. They said one of the advantages the Japanese had were their torpedoes. They said that the japanese torpedoes were different with how they used or stored their air to propel the fish through the water, and that it did not leave any bubbles like allied torpedoes.

Does this mean that in AH all IJA/IJN torpedoes should NOT display a wake when launched?

Imagine trying to jink carriers around them, or guide them in. During scenarios or just plain old MA use, it would be interesting, no?


Just wondering if there's anything to this, or if it's just "History Channel Strikes Again"?

[Soulyss]

Not an expert but I believe that the Japanese torpedo's, or at least the vaunted Long Lance torpedo used pure oxygen rather than compressed air.  They were supposed to leave less visible wakes, but you still were releasing a gas underwater so I would think that a wake would still be present.

Grabbed this off wikipedia so take it for what it's worth

The Japanese Navy invested heavily in developing a large, heavy, and long-range torpedo, the Type 93. Torpedoes are one of the few naval weapons enabling small warships, such as destroyers, to damage battleships. IJN torpedo research and development focused on using highly-compressed oxygen instead of compressed air  (which is about 21% oxygen) as the torpedo's fuel oxidizer in its propulsion system, feeding this into an otherwise normal wet-heater engine burning a fuel such as methanol or ethanol. Pure oxygen provides five times as much oxidizer in the same tank volume, increasing speed and range, and the absence of inert nitrogen reduced the gasses emitted to carbon dioxide, which has significant solubility in water, and water vapor, much reducing the tell-tale bubble trail. However, like all torpedoes, when fired at night it produces an unavoidable wake of luminescence in the ocean.

[Krusty]

I believe that is the one they mentioned: "long lance" -- I simply forgot it at the time of posting.


P.S. That's an interesting "when fired at night" comment. I wonder if that did not apply to "during the day"?

[Charge]

"I wonder if that did not apply to "during the day"?"

Maybe it has something to do with the amount of light reflecting from the surface of water during daytime?

-C+

[Noah17]

One of the more/most important advantages of the "Long-Lance" was it's range. The bubbles?....IMO i think if you're close enough to see them from a ship it's probably too late anyway.

The Long lance that I've always heard discussed was not an aerial torpedo. It was fired from ships and subs. The range was 2-3 times that of American torps and it was much more dependable. American torpedo's were having serious issues for the first half of the war. The magnetic detonators were not registering correctly and the contact detonators broke more than half the time on impact; failing to detonate.

I believe the Japanese aerial torpedo was more dependable, could be dropped from slightly greater height and, at slightly greater speed. If you're flying the plane that's certainly an advantage.
 

[maddafinga]

I believe that is the one they mentioned: "long lance" -- I simply forgot it at the time of posting.


P.S. That's an interesting "when fired at night" comment. I wonder if that did not apply to "during the day"?

I don't really know jack about torpedoes, but I grew up on the gulf and spent a lot of nights out at the bay house fishing.  I can tell you that there are bio luminescent creatures in the water that glow red and green mostly when it's disturbed.  As the tide runs past dock posts they'll leave little glowing wakes, if you dip your hand in and stir it around it stirs up little glowing patches in the water.  They only last briefly past the disturbance that causes the glow, but they're visible.  And they're only visible at night.  When it's really dark, like it got out at the bay house with not power for miles around, the glows really stand out pretty well. 

[Krusty]

Very interesting Madda. Thanks for sharing.

Noah, I cannot recall if the blurb on the TV show mentioned ship-borne or airborne launching of the torp. You may be right about it being a ship-based fish in which case it's a moot point as far as AH is concerned.

[OOZ662]

American torpedo's were having serious issues for the first half of the war. The magnetic detonators were not registering correctly and the contact detonators broke more than half the time on impact; failing to detonate.

Not to mention that they ran about 10 feet deeper than the set run depth. That may have only been an issue for submarines and ships (since you can't very well set a depth from the wing of a plane), but it certainly hindered the performance of the torpedo.

I only know it from a sub commander's point of view, but a torpedo works best if magnetically detonated just below the ship, not a direct impact like the movies show. Such a blast breaks the back of the ship. American submariners generally set their torpedo to run at the very shallowest depth with both magnetic and impact triggers set. If the torp ran deep, it would (hopefully) magnetically detonate and break the structure. If it ran shallow, it'd blow a hold in the side. But even then, if it hit at too shallow of an angle, the explosive's firing pin would bend and the torpedo wouldn't detonate.

[chewiex]

........  I can tell you that there are bio luminescent creatures in the water that glow red and green mostly when it's disturbed.  As the tide runs past dock posts they'll leave little glowing wakes, if you dip your hand in and stir it around it stirs up little glowing patches in the water.  They only last briefly past the disturbance that causes the glow, but they're visible.  And they're only visible at night.  When it's really dark, like it got out at the bay house with not power for miles around, the glows really stand out pretty well. 

Not to jump off topic, but, to add to Madda's story....

We get that quite often here in Florida where I live. Depending upon how much rain we get through the summer months, we get a lot of algae and organisms that ingest phosphorus from the drainage runoffs and naturally occurring phosphorus in our waterways.  Its a spectacular sight to behold when on a dark moonless night, out on a calm body of water and you see glowing swirls in the water caused by schools of fish swimming through an algae bloom. Sometimes it gets as bright as a blueish-green glow stick. Sometimes even a glowing trail behind the boat that seems to stretch a hundred yards at a time. Very cool and beautiful. Can only imagine what it would look like trailing a fast torpedo.

[theNewB]

There was also a shortage of torpedos and manufacturing plants for them, think i remember reading somewhere that in fall of 42 10 patrol subs left pearl and 2 of those were equiped with only mines. the Mk XIV torp was really limited in range. the sub version of the long lance type 95 was a 900lb torp rated at 10,000yrds at 45kt, believe sub version was produced in both electric and oxygen, so would mean a lot less bubbles compaired to steam.compaired to a 500lb torp rated at 4500yrds @ 46kts. after july 44 once US torp producers ironed out the bugs mix of types was 75% electric to 25% steam. but they still had problems until the end of the war.

[branch37]

correct me if im wrong but i seem to recall hearing something about early American torpedoes malfunctioning and going in a circle after launch and comming back at the sub that launched it? 

[Krusty]

I doubt they were worried, chances were even on the odd chance it hit them after looping back that they would be perfectly fine, aside from the ringing in their ears.

[Soulyss]

correct me if im wrong but i seem to recall hearing something about early American torpedoes malfunctioning and going in a circle after launch and comming back at the sub that launched it? 

There were several issues with the USN's torpedo's early in the war, I'm not an expert but the two most common faults I've come across had to do with the fuses, there were a lot of duds that never went off the other was a fault depth setting.

Jim Guyton, a TBF crewman who was flying off the Enterprise had the following to say.

... In the TBF ther was a little door on the starboard side with a crank inside.  You'd use it to set the depth of the torpedo run.... We suspected that a lot were not set right:  If you set it six it might run at twenty.  But we could never prove anything.  We did get torpedo hits on the transports on the canal and they were set at six.  Later we got a torpex warhead and it put a good dent in a ship.  In '42 the warhead was quite small.  That's why sometimes a Japanese ship would take several hits and not sink right away - which is amazing when you think about what a torpedo is supposed to do.  The Japanese models did more damage and you were in trouble if you hit by one.  You look at photos at the Japanese Kate bombers and you see that big torpedo of theirs sticking way out, like it's leading the plane along.

[OOZ662]

I doubt they were worried, chances were even on the odd chance it hit them after looping back that they would be perfectly fine, aside from the ringing in their ears.

Actually, there were a few subs believed to be sunk by circle runners. The worry was enough to have a step put in place in the common tactics of submarines specifically to move out of the way should the torpedo run around. The "guidance" system on a torpedo uses a gyro setting to tell it "come out of the tube, turn X degrees in Y direction, then run straight until detonation or zero fuel." Sometimes it didn't stop turning. A self-impact was made more rare by the submarines' tendency to dive deep after firing torpedoes to avoid escorts, but during attacks on solo or small convoy merchant shipping it could be a real problem.

I believe the famous USS Wahoo was sunk by her own torpedo, though I was reading a lot of articles back then and may have confused it with another.

EDIT: Here's the thread that inspired my research back then.

[Krusty]

OOZ, I was making teh funneh about how the torps were ineffective even when they HIT their targets.