RE: IJN Battleship availability chart

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RE: IJN Battleship availability chart - 5/31/2015 12:36:51 AM

spence

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quote:

August - September 1942:
Kure and Yokosuka. KITAKAMI and OI are converted to fast transports. Their ten quadruple TT are reduced to six, for a total of 24 tubes. They are equipped with two Daihatsu barges and fitted with two triple mount Type 96 25-mm AA guns. Depth charge launching rails are also installed.

From TROMs of Oi and Kitikami at CombinedFleet.com

That explains that. Apparently the performance of Type 93 torpedoes in action up to that time (Java Sea) was not that impressive. Somebody figured it out: something of the order of low single digits up to then. Even at night they'd only sunk more Japanese ships (Oops) than Allied ones (Sunda Strait).

Those two CLs spent the time prior to their conversion as escorts to the Batdivs. As such they had done exactly nothing of note.

The photo is enhanced to show who was doing the shooting but anybody can find more than one photo showing both US carriers/desroyers off Samar with a Japanese CA on the horizon. One shot from USS Kitkun Bay shows Gambier Bay under fire from an IJN cruiser on the horizon - the Kitkun Bay is a good 2000 yds from Gambier Bay and the IJN cruiser is around 10000 yards beyond Gambier Bay. According to maps of the action that is about as close as they got before the IJN broke off. All that is irrelevant though. From my experience at sea the visibility was about as good as one has reason to expect at sea (admittedly my experience is all in the Atlantic). The horizon appears to be quite clear and that allows accurate celestial navigation (sun lines). The IJN BBs got exactly the "Decisive Battle" that they had practiced for. They blew it. Rating them as far more experienced than US BBs is just an IJN Fanboy wetdream and nothing more.

(in reply to ChuckBerger)

Post #: 31

RE: IJN Battleship availability chart - 5/31/2015 1:17:27 AM

Symon

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quote:

ORIGINAL: jamesjohns
Thanks for the numbers showing the fuel issue Japan faced in WWII. I knew they had problems and the Yamato was a 1 way trip due to fuel but to see the numbers really sheds new light on it, hard to fathom the amount needed to move a ship, let alone a BB.

Any idea in US gallons how much it is?

When talking about ships, the gallons don�t matter as much as the specific heat per unit mass. So tons of fuel is a true measure. It�s that ancient question; what weighs more, a pound of feathers or a pound of lead? But here�s some numbers for comparison.

#2 Residual Fuel Oil (as close to bunker-C as we come today) works out to 6.7 barrels per ton. Compare with Industrial Diesel Fuel at 7.5 barrels per ton. A barrel of petroleum is a volumetric containing 42 US gallons (liquid).

So 281.4 US gallons per ton, for Bunker-C equivalent fuel. 315 US gallons per ton, for industrial grade diesel fuel.

So looking at a minimum of 1.13M gallons for the short mission; 2.90M gallons for the longer one.

That's a lotta gas.

Ciao. JWE

_____________________________

Nous n'avons pas peur! Vive la libert�! Moi aussi je suis Charlie!
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Post #: 32

RE: IJN Battleship availability chart - 5/31/2015 2:08:04 AM

wdolson

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From: Near Portland, OR
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quote:

ORIGINAL: wdolson

Sorry, didn't make it clear we were in agreement.

Bill

quote:

ORIGINAL: Zorch
Agree with you both - besides the fuel issues, cruisers were the best ships for the Solomons campaign. I don't understand why Oi and Kitakami weren't used there. A broadside of 40 torpedoes at night would have been even more devastating than the historical ones.

The problem was they had a glass jaw. One 5 inch hit in the torpedo mounts and boom!

The problem with making torpedo runs is the ship doing it is fairly vulnerable on the run in.

Bill

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(in reply to Zorch)

Post #: 33

RE: IJN Battleship availability chart - 5/31/2015 3:41:10 AM

Veer

Posts: 2231
Joined: 6/25/2002
From: Excuse me
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quote:

ORIGINAL: spence

From TROMs of Oi and Kitikami at CombinedFleet.com

That explains that. Apparently the performance of Type 93 torpedoes in action up to that time (Java Sea) was not that impressive. Somebody figured it out: something of the order of low single digits up to then. Even at night they'd only sunk more Japanese ships (Oops) than Allied ones (Sunda Strait).

Those two CLs spent the time prior to their conversion as escorts to the Batdivs. As such they had done exactly nothing of note.

The photo is enhanced to show who was doing the shooting but anybody can find more than one photo showing both US carriers/desroyers off Samar with a Japanese CA on the horizon. One shot from USS Kitkun Bay shows Gambier Bay under fire from an IJN cruiser on the horizon - the Kitkun Bay is a good 2000 yds from Gambier Bay and the IJN cruiser is around 10000 yards beyond Gambier Bay. According to maps of the action that is about as close as they got before the IJN broke off. All that is irrelevant though. From my experience at sea the visibility was about as good as one has reason to expect at sea (admittedly my experience is all in the Atlantic). The horizon appears to be quite clear and that allows accurate celestial navigation (sun lines). The IJN BBs got exactly the "Decisive Battle" that they had practiced for. They blew it. Rating them as far more experienced than US BBs is just an IJN Fanboy wetdream and nothing more.

The problem is the game doesn't model experience degradation as occurred in history. Experience does not remain steady in the absence of action, it needs to be continually honed via training and drills (and shore rest/home leave because the South Pacific was fairly brutal weather wise). From 1941 onwards all were in short supply for the Japanese - for their infantry, air crews and ship crews. Many histories, even the Japanese high command, noted that veteran pilots no longer performed as well as they did by mid 1942 let alone 1944. The same would be true for their seamen.

The fact that the Japanese kept most of their capital ships in the South Pacific - where training facilities were close to nil, or in port due to a lack of oil and threat of subs, certainly didn't help.

edit: we saw a similar capability degradation in the German High Seas fleet during WW2. After being pretty much confined to port after Jutland, crack crews became bored, lazy and finally mutinous.

< Message edited by Veer -- 5/31/2015 4:43:48 AM >

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Post #: 34

RE: IJN Battleship availability chart - 5/31/2015 3:43:55 AM

jamesjohns

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Thanks Symon, huge amount of fuel no doubt

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Post #: 35

RE: IJN Battleship availability chart - 5/31/2015 9:45:25 AM

Zorch

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quote:

ORIGINAL: wdolson

quote:

ORIGINAL: wdolson

Sorry, didn't make it clear we were in agreement.

Bill

quote:

ORIGINAL: Zorch
Agree with you both - besides the fuel issues, cruisers were the best ships for the Solomons campaign. I don't understand why Oi and Kitakami weren't used there. A broadside of 40 torpedoes at night would have been even more devastating than the historical ones.

The problem was they had a glass jaw. One 5 inch hit in the torpedo mounts and boom!

The problem with making torpedo runs is the ship doing it is fairly vulnerable on the run in.

Bill

The long lances had such a long range, and most of the battles being at night would mitigate that weakness. They should have been ordered to withdraw after firing their broadsides. The Tokyo Express could have benefited from them.

(in reply to wdolson)

Post #: 36

RE: IJN Battleship availability chart - 5/31/2015 11:03:44 AM

wdolson

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From: Near Portland, OR
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Theoretical range and real world range are two different things. The Japanese never used the long lance at its maximum range. The problem with torpedoes of the 1940s was once they were in the water, their trajectory became known by the enemy and the further the torpedo had to travel, the more time the enemy had to get out of the way. So even if you have a torpedo with an extremely long range, you don't want to launch at max range unless it's an emergency. In ideal conditions you want to launch at the minimum range that would allow the torpedo to arm before reaching the target, though that could be suicidal against a strong enemy force, so in practice a compromise range is used that is not minimum range, but is relatively close.

This is also the reason B-17s dropping from altitude couldn't hit a moving ship in the real world. No matter how good the bomb sight, it took time for the bomb to fall from altitude and gave all but the slowest moving ships plenty of time to get out of the way.

I suggest reading this article:

http://www.navweaps.com/index_tech/tech-067.htm

It examines every time the long lance was used and its effectiveness in the real world. If anything, the game overrates them.

Bill

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(in reply to Zorch)

Post #: 37

RE: IJN Battleship availability chart - 5/31/2015 3:32:49 PM

Buckrock

Posts: 578
Joined: 3/16/2012
From: Not all there
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quote:

ORIGINAL: Jorge_Stanbury

The Japanese were in trouble!

according to HP Willmotts "Empires in Balance" I quote:

"With or without war and with or without the indies, the Japanese had problems -- if their calculations were accurate.
It almost goes without saying, however, that their figures were wildly inaccurate. The Japanese vastly overestimated their own potential and drastically underestimated their requirements. The notion of a single major engagement showed that the navy really had no inkling of the kind of war it was going to fight. In the first year of the war the navy used 60 percent more oil that it was allowed under any review or plan. Its operations consumed 30,520,000 barrels - 80 percent of the assessed national needs for 1941-1942. Its declining needs thereafter reflected its losses, not its commitments. The Indies maximum production was about 16,670,000 barrels in 1943, actually more than allowed for in the August review, but outflow to Japan fell 60 percent in 1944, mainly because of tanker losses and direct fueling of the navy in southern ports. Domestic production never exceeded 3,400,000 barrels in a year (1943)"

The plans he is referring are:
- Estimates done by the joint Army-Navy committee done in June 1941. This assumed a shortage of 4.4 million barrels in September 1944
- Navy revision done in August 1941: this saw a period of crisis - low reserve, no shortage - from September 1943 to September 1944.
The navy revision assumed significant increases in production in the 3rd year of war, for both the DEI (30,000,000 barrels) and domestic production (4,500,000 barrels). This estimates were very far away from reality

I was only addressing the relative fuel oil cost of conducting the Midway/Aleutian operation in relation to Japan's actual 1942 supply (including the better than planned early output from the East Indies).

Willmott's figures though are a good guide as to Japan's problems in getting through a war they expected might take up to three years.

Even before the war they had recognized a "slight" problem if it went into a third year. It's little surprise then if they were prepared to ignore their oil budget during 1942 in the hope that some decisive victory against the USN might be gained early.

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Post #: 38

RE: IJN Battleship availability chart - 5/31/2015 3:35:59 PM

Buckrock

Posts: 578
Joined: 3/16/2012
From: Not all there
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quote:

ORIGINAL: wdolson
I suggest reading this article:

http://www.navweaps.com/index_tech/tech-067.htm

It examines every time the long lance was used and its effectiveness in the real world. If anything, the game overrates them.

Bill

Are you referring to them being over-rated due to their accuracy (in the database) or their performance in the game? Just curious as I
tend to gain few decisive results with them in surface combats during games against the Allied AI.

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Post #: 39

RE: IJN Battleship availability chart - 5/31/2015 4:17:29 PM

Zorch

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quote:

ORIGINAL: wdolson

Theoretical range and real world range are two different things. The Japanese never used the long lance at its maximum range. The problem with torpedoes of the 1940s was once they were in the water, their trajectory became known by the enemy and the further the torpedo had to travel, the more time the enemy had to get out of the way. So even if you have a torpedo with an extremely long range, you don't want to launch at max range unless it's an emergency. In ideal conditions you want to launch at the minimum range that would allow the torpedo to arm before reaching the target, though that could be suicidal against a strong enemy force, so in practice a compromise range is used that is not minimum range, but is relatively close.

This is also the reason B-17s dropping from altitude couldn't hit a moving ship in the real world. No matter how good the bomb sight, it took time for the bomb to fall from altitude and gave all but the slowest moving ships plenty of time to get out of the way.

I suggest reading this article:

http://www.navweaps.com/index_tech/tech-067.htm

It examines every time the long lance was used and its effectiveness in the real world. If anything, the game overrates them.

Bill

Thank you. It has the very interesting observation that torpedo speed may have been more important than range.
A good book on the technical aspects is Torpedo: The Complete History of the World's Most Revolutionary Weapon by Roger Branfill-Cook.

(in reply to wdolson)

Post #: 40

RE: IJN Battleship availability chart - 5/31/2015 9:33:22 PM

wdolson

Posts: 10398
Joined: 6/28/2006
From: Near Portland, OR
Status: offline

quote:

ORIGINAL: wdolson
I suggest reading this article:

http://www.navweaps.com/index_tech/tech-067.htm

It examines every time the long lance was used and its effectiveness in the real world. If anything, the game overrates them.

Bill

quote:

ORIGINAL: Buckrock
Are you referring to them being over-rated due to their accuracy (in the database) or their performance in the game? Just curious as I
tend to gain few decisive results with them in surface combats during games against the Allied AI.

Performance. The USN and RN moved away from torpedoes except for subs as the war went on. TBFs dropped a heck of a lot more bombs than torpedoes, even on ships. Torpedoes were reserved for the big ships that could survive many bomb hits.

By 1944 they were being removed from DDs. Almost all Fletchers has at least one torpedo mount removed by mid-44 to provide more space for AA. Usually more 40mm mounts.

The Japanese held onto to potential torpedo long after its effectiveness was proven to be less than its potential. But even then they were moving away from torpedoes by late 44. One torpedo cruiser was sunk, but the other was converted to a kaiten carrier.

Bill

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WitP AE - Test team lead, programmer

(in reply to Buckrock)

Post #: 41

RE: IJN Battleship availability chart - 5/31/2015 11:40:57 PM

spence

Posts: 5400
Joined: 4/20/2003
From: Vancouver, Washington
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In only one case was the long range of the Type 93 of significance: in 1943 the USS Strong was struck by a torpedo launched from some IJN ships that appeared on the edge of its radar scope at the radar's extreme range for just a few minutes. The original Navy investigation of the sinking concluded that the Strong had hit a mine since "everybody knew a torpedo couldn't go that far".

The game doesn't seem to overstate the effectiveness of the Type 93 too badly although it seems to grossly overrate the effectiveness of the IJ's aerial torpedo (in almost any given engagement the KB's Kates will score as many hits in that one engagement than they did IRL during the whole of 1942 (when they scored all of their hits excepting those scored at Pearl Harbor)).

(in reply to wdolson)

Post #: 42