Type 93 Torpedo What-If

[FleetAdmiral]

What if the Japanese developed a wire-guided varient of their Type 93 Long Lance Torpedo before the outbrake of war? Would it be possible? Would it work?

My thoughts:
10,000 yards max distance of control (max length of control wire)

Control ->Only one weapon would be fired at a time. The ship's hydrophones would be used to keep a fix on the direction of the launched torpedo. That information would be transmitted to the fire control board's "compass" - a coloured needle. Additionally, the look direction of the torpedo director (centered on target) would also be transmitted to control board's "compass" - a second coloured needle. The fire controller would then align the torpedo to the look direction in order to hit the target. Additionally, the distance travelled by the torpedo (transmitted from the control wire spool) would be on the board as well.

The idea being that only 2 such weapons would be carried in the loadout. Since the Japanese tended to have aggressive torpeod tactics. Once the enemy reaches 10,000 yards, the special Type 93s would be used against enemy cruisers, and if possible destroyers. If hit, the target would loose speed and maneovrability, and thus be easier targets to hit and sink with the conventional Type 93s.

[Apocal]

The control system you hypothesized is, I almost want to say out of reach of WW2, though nothing outlandish about it stands out except for 10Kyards of wire. It's around five nautical miles dude. That's a lot of wire. But the control wire spool to determine range is a good idea.

A slight fire control problem would be accurately determining the torpedo's bearing at longer ranges, it's not horribly visible and I'm not quite sure if Japanese destroyer sonar had the bearing resolution or even effective range to determine where exactly the torpedo was.

Those issues aside, handwaving if necessary, are you looking for a description of how this would change things tactically? Or how it would affect the war overall? Overall the outcome would hardly change at all. They'd win a few more night surface actions between destroyers and a cruisers, they'd hit and sink more ships in the fights they did lose anyway, but ultimately it's not going to get supplies to the homeland or stop the Navy/Marine Corps juggernaut from rampaging through the Pacific.

Tactically though, it allows for some fairly interesting move/countermove things, even moreso when you consider a torpedo loud enough to be heard by the Japanese is probably loud enough to be heard by the Americans as well. Though, once again, I haven't heard of many references to torpedoes being heard by surface ships during WW2. I don't know if it's the result of doctrine (Sonar watch only set at Condition II or Condition I AKA General Quarters) or of limitations in sonar sets of the time. Presuming it can be heard by the Japanese, it's entirely possible the Americans can hear it as well and so it may actually blow the element of surprise in a lot of battles.

That being said, the concept of operation you laid out is a little bit ridiculous. Once those torpedoes hit, they are going to know somewhere nearby is the IJN, searchlights are gonna come on, guns are gonna start barking and every ship is going to start maneuvering erratically, even dangerously. It may very well be that your only good opportunity to fire a conventional spread of torpedoes will be lost.

A better method, in my opinion of course, would be a spread to cover the formation and use the special torpedo to "single out" the probable flagship and thereby send command and control out of the fight.

[MarekGutkowski]

Wire guided torpedo will be a nice trick what You are looking fore is wake homing torpedo with is even less likely with WWII tech.

Beside any force add to WWII Japan will not change the strategic position.
Give IJN 1960's tech and they still loose(no nuke), US will simply zerg rush them.

[FleetAdmiral]

I am well aware of Japan's strategic position, I am looking at the tactical implications of a wire-guided torpedo.

I first thought of mounting an accoustic tracker to the Type 93, but realized that all acoustic tracking torpedoes were all the quieter electric type.

At second I considered having a wire-guided special Type 95 Submarine Torpedo with some 1,500 yards of wire. But the problem was how to ensure that the guide wire be cut after hitting the target. If the wire did not cut, then the sub has the problem of a flooded tube and dragging that guide wire - thus adversely affecting operations until it can surface so that the crew can cut the line. Hence, I turned to the Type 93 Long Lance - where such a problem will not occur.

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I originally chose the 10,000 yards of guide wire as that permitted a large engagement radius.

Instead of 10,000 yards of guid wire, would 5,000 yards be more realistic?

The only other way I know how to get around the hydrophone sensitivity range would be mounting the guide wire spool on its own turret which moves in parallel with the torpedo director. The guide wire would pass through a ring with a single pivot that would measure the degree of wander (port/starboard) which is transmitted to the control board's "compass". This ring is located at the "muzzel" of the wire spool. All other weapon operation remains the same.

[Apocal]

Originally Posted by FleetAdmiral

At second I considered having a wire-guided special Type 95 Submarine Torpedo with some 1,500 yards of wire. But the problem was how to ensure that the guide wire be cut after hitting the target. If the wire did not cut, then the sub has the problem of a flooded tube and dragging that guide wire - thus adversely affecting operations until it can surface so that the crew can cut the line. Hence, I turned to the Type 93 Long Lance - where such a problem will not occur.

I don't know how familiar you are with WW2 subs and their tactics and such, but 1500 yards is pretty much spitting distance. Past about 2500 is where you meet a higher class of submariner. At any rate, why not a facility to manually cut the wire then force it out along with the waterslug when you go to reload the tube?

I originally chose the 10,000 yards of guide wire as that permitted a large engagement radius.

Yeah, I figured as much, although as night actions in the Solomons proved, the Japanese were quite adept at hitting with Long Lances from 10 grand out, without wire guidance. And we're talking multiple ships hit in the space of one or two minutes, each destroy hitting .7 ships, which is, tactically speak, very effective. Undoubtedly, some spreads hit nothing, while others hit multiple ships.

And when a Long Lance hit, whew buddy, it fucking hit.

Instead of 10,000 yards of guid wire, would 5,000 yards be more realistic?

From a technical feasibility standpoint, yes. Tactically, that's nearly useless for the Japanese, their destroyers only scored so heavily with Long Lances insofar as the USN had no fucking clue it's range was 10 grand. Those battles that the Japanese won, in every single one of them, the Americans knew they were there and exactly where they were, thanks to radar sets with every task force at least and likely most ships.

With a guided 10Kyard range, you still have some tactical possibilities you wouldn't otherwise have, such as being able to launch an effective torpedo attack after the gun battle is joined and ships have begun maneuvering wildly. Although that is entirely dependent on the ability of the firing ship to be able to maneuver wildly as well or having a willingness to sail straight and true while being pounded on by gunfire.

The only other way I know how to get around the hydrophone sensitivity range would be mounting the guide wire spool on its own turret which moves in parallel with the torpedo director. The guide wire would pass through a ring with a single pivot that would measure the degree of wander (port/starboard) which is transmitted to the control board's "compass". This ring is located at the "muzzel" of the wire spool. All other weapon operation remains the same.

I've never heard of such a control scheme before so I can't really comment on it.

[FleetAdmiral]

Originally Posted by Apocal

I don't know how familiar you are with WW2 subs and their tactics and such, but 1500 yards is pretty much spitting distance. Past about 2500 is where you meet a higher class of submariner. At any rate, why not a facility to manually cut the wire then force it out along with the waterslug when you go to reload the tube?

My original concern with a wire guided Type 95 was how to guarentee cutting the guide wire so that the outer hatch to the tube can be closed. My idea for a 1,500 yard guide wire weapon would be to assist the Japanese in dealing with one of the problems encountered historically, but also revealed during their annual fleet war games starting in 1938 - attacking fast warships (interestingly in those games revealed that the sub performed well against shipping attacks). While the Germans developed their accoustic torpedo to deal with Allied destroyers, my intention is giving the Japanese a similar weapon that could also deal with Allied destroyers - thereby helping to reduce submarine losses.

This then facilitates the question. Would a 1,500 yard guided wire torpedo be effective in helping to reduce the destroyer threat?

With a guided 10Kyard range, you still have some tactical possibilities you wouldn't otherwise have, such as being able to launch an effective torpedo attack after the gun battle is joined and ships have begun maneuvering wildly. Although that is entirely dependent on the ability of the firing ship to be able to maneuver wildly as well or having a willingness to sail straight and true while being pounded on by gunfire.

Though, a 5,000 yard guide wire weapon would probably be reserved in a night battle then, after the main torpedo barrage?

[Apocal]

Just so you know, from you first post, I thought you'd meant a destroyer torpedo, not a sub one, I wasn't actually specifically thinking subs in my response. Although the point still stands that once a ship explodes, any hope for straight-running torpedoes is done for.

Originally Posted by FleetAdmiral

This then facilitates the question. Would a 1,500 yard guided wire torpedo be effective in helping to reduce the destroyer threat?

Yes, undoubtedly. Although it's probably better spent on attacking high value targets, since we had about ten destroyers or destroyer escorts to throw at every Japanese sub.

Though, a 5,000 yard guide wire weapon would probably be reserved in a night battle then, after the main torpedo barrage?

Possibly. Tactically, they would complement each other rather well, as you get a near-guaranteed hit, plus with a good setup, decent chance of multiple hits. I'm not sure if the Japanese used any wolfpack tactics, but combining multiple boats and simple fire control measures, such as lead-trail, left-right or 1-2-1-2, would be devastating even to well-guarded ships.

Although the inability to dive or really maneuver might cost more boats. But they were losing boats anyway, so might as well make it mean something.

[FleetAdmiral]

My OP dealt only with the Type 93 24-inch torp used on destroyers and cruisers. Although due to our discussions I expanded the debate to the Type 95 21-inch torp for subs.

My intention, with your inputs suggest 5,000 yards is a realistic wire-guided weapon for the Special Type 93. And 1,500 yards wire guided for the Special Type 95 is also realistic.

This brings another interesting question. When discussing the sub Special Type 95 torp, (say 4 are included in the sub's weapon loadout), with the lesser range dictated by the wire (and compounded its assembly in the tube), would it be practical/desirable to increase the warhead size from 405 to 500 kg while maintaining a maximum range of 2,500 with the torp running at maximum speed?

My understanding is that the IJN did not use wolfpacks. Rather they treated their subs like ordinary surface ship assets - hence the development and construction of large "command" subs - the AM series.