Japanese shadow destroyers

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No I don't mean Shadow vessels from Babylon 5.


In the London- naval treaty ships below 600 tons are exempt from any classifications, in OTL Japan used this clause to build a crap-load of fairly crappy torpedo-boats.


However there is also another clause that says that ships between 601-2000 tons are exempt if they don't carry a gun larger then 6,1”/155mm, no more then four guns above 3”/76mm, aren't fitted or designed with torpedoes and aren't designed for above 20 knots.


So let's assume that the Japanese didn't care about that “designed” part, they cheated quite blatantly everywhere else so why not here.


So what if the Japanese design a 1500-2000 ton “gunboat” with three 155mm guns in single turrets and a speed of 20 knots. These “gunboats” are designed to be upgraded to fleet destroyers rather quickly, changing the single 155mm guns to dual 127mm guns, adding torpedoes and another boiler to up the speed to 33-35 knots.


How feasible and expensive would it be?
 

I'm not sure exactly what provisions there were for enforcement in the London and Washington treaties, probably not a whole lot given how everyone basically stopped adhering to them the moment they thought they could get away with it. At any rate it seems to me that if you're already cheating this badly, you might as well just build the ship with the extra boiler already in place and just tell everyone "Yeah its top speed is definitely 20 knots". That's the thing that would slow you down the most to add after all.
 
A more than 50% increase in speed would require a vast increase in power, so much in fact that the ships would have to have a lot of empty space to allow for the extra turbines. (The Hunt class had five times the HP of the Black Swan for a 35% increase on speed on roughly the same displacement)
The best way to use the under 2000t rule would be to build sloops, and free destroyers from escort duties.
 

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I'm not sure exactly what provisions there were for enforcement in the London and Washington treaties, probably not a whole lot given how everyone basically stopped adhering to them the moment they thought they could get away with it. At any rate it seems to me that if you're already cheating this badly, you might as well just build the ship with the extra boiler already in place and just tell everyone "Yeah its top speed is definitely 20 knots". That's the thing that would slow you down the most to add after all.

That's an idea. I'll have to look into it.

A more than 50% increase in speed would require a vast increase in power, so much in fact that the ships would have to have a lot of empty space to allow for the extra turbines. (The Hunt class had five times the HP of the Black Swan for a 35% increase on speed on roughly the same displacement)
The best way to use the under 2000t rule would be to build sloops, and free destroyers from escort duties.

Sloops wont sell to the Japanese navy, not "sexeh" enough, if you get my meaning. Even if it's for the purpose of freeing up destroyers for other duties. Hence my proposal of "shadow destroyers", in essence gunboats that can be upgraded to destroyers fairly quickly.
 

GarethC

Donor
Have an increase in Soviet sub deployments to the Pacific, or construction if following Rozhtdestvensky's route is too tough, say in 1932, which causes consternation in the Army with the threat to the SLOC to the China, so that the IJA takes ASW seriously and goes for the construction of sub chasers in numbers and the evolution of convoy doctrine, maybe?
 
Another problem is that this strategy only clears one bottleneck, which is yard space. Granted, that was a serious problem for the Japanese, but it's still only one bottleneck. It does nothing to help the long lead time of engines or gun turrets.
 

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Another problem is that this strategy only clears one bottleneck, which is yard space. Granted, that was a serious problem for the Japanese, but it's still only one bottleneck. It does nothing to help the long lead time of engines or gun turrets.
Not for destroyer sized ships, the Japanese could easily have built an additional 30-40 destroyer sized ships during the war going by yard space only as they had several underutizlized yards, particulary the Sasebo Naval Yard.
 
No I don't mean Shadow vessels from Babylon 5.


In the London- naval treaty ships below 600 tons are exempt from any classifications, in OTL Japan used this clause to build a crap-load of fairly crappy torpedo-boats.



How feasible and expensive would it be?

That "crap-load" was only a small group of 4 ships. The IJN then realised, like the RM had, that mini destroyers need not be that mini and build bigger, better torpedo boats.
http://www.navypedia.org/ships/japan/jap_tb_tomozuru.htm

http://www.navypedia.org/ships/japan/jap_tb_otori.htm
Note that the second batch if Otori class TB was canceled in favour of ASW ships.

And the IJN was not that averse to ASW as is often claime, at least when it came to building programs . They built a number of Sub chasers, a few sloops and converted their old destroyers for escort duties. By the time submarines become an issue, they had limited capability and were in desperate need of anything.
 
I do not disagree, I just doubt the Imperial Japanese Navy would agree with the fact that they need them.

If you go to navypedia, and do a quick list of ASW ships ordered prewar by the major navies, the IJN is actually quite well represented. They did fail to anticipate the scale and power of the USN submarine offensive, but they did fail to anticipate (or choose to ignore) the scale and power of just about anything in the USN.
 

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That "crap-load" was only a small group of 4 ships. The IJN then realised, like the RM had, that mini destroyers need not be that mini and build bigger, better torpedo boats.
http://www.navypedia.org/ships/japan/jap_tb_tomozuru.htm

http://www.navypedia.org/ships/japan/jap_tb_otori.htm
Note that the second batch if Otori class TB was canceled in favour of ASW ships.


Damn you are annoying with that edit button.... at least three edits before I get my reply...

I consider 12 torpedo-boats of the Chidori- and Ōtori-classes a crapload, everything is relative.

And the IJN was not that averse to ASW as is often claime, at least when it came to building programs . They built a number of Sub chasers, a few sloops and converted their old destroyers for escort duties. By the time submarines become an issue, they had limited capability and were in desperate need of anything.

That's when the war started, prior to the war, not so much.
 
Damn you are annoying with that edit button.... at least three edits before I get my reply...

I consider 12 torpedo-boats of the Chidori- and Ōtori-classes a crapload, everything is relative.



That's when the war started, prior to the war, not so much.

The edit was for inserting quotes. Not expecting to have someone reading live. I'll try to refrain from it. Pre war for the IJN is up to December 1941. But even if you stick to Pre 1940 orders, that includes a lot of sub chasers, sloops, and you must factor in the fact that their minesweeper had an escort capability.
Its not as bad as they are often accused of.
 
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