Japanese Warship Construction

[Saburo Kurusu]

Thanks very much JWE, for your detailed and extreeeemly interesting insight into the secrets of Japanese shipbuilding!

[&o]

[herwin]

I strongly suspect it was "Jobs for the Boys" until it was too late.

[GaryChildress]

ORIGINAL: JWE

Just for fun, here’s the actual construction scheds (keel-to-launch) for the only four yards capable of building a capital ship. A BB or large CV (Taiho/’Kaku) required a 300m slipway (only 3 in existence). A CA or Unryu type CV required a 225-250m slipway (only 3 in existence by end of war). They were actually utilized pretty well … hull # 111 and Shinano seem to be the only major abortions.

Why was hull # 111 aborted? If I'm not mistaken it would have been the 4th Yamato, correct? Judging from your chart, it almost looks like #111 could have been completed and construction on Katsuragi only minimally delayed.

EDIT: Actually maybe it would have thrown Katsuragi off by a year. But toward the end of the war BBs were probably more valuable to Japan than carriers without combat air groups. At least another Yamato could have caused the Allies to use up few dozen more torpedos.

]

[Mac Linehan]

ORIGINAL: Saburo Kurusu

Thanks very much JWE, for your detailed and extreeeemly interesting insight into the secrets of Japanese shipbuilding!
[&o]

Well put, Saburo; I also, am most grateful.

Thank you, JWE!

Mac

[GaryChildress]

Kudos indeed! One more question for JWE...

Where did you get all this marvelous data from? Are the charts entirely of your making or did you get them from a book or website? I'd like to get a nice graphical representation of the entire Japanese building program from 1930 - 1945 if it is available. [8D]

[GaryChildress]

Also one more question since we have this fantastic graphical illustration available. Thank you again JWE for the info!

It appears some ships were laid down with several months gap in between use of the slipway. I wonder if it is not plausible that Japan could have made better use of the slips by starting projects sooner after completed ones. It looks like Kobe #1 was by far the most efficiently used slip between 1938 - 1945.

[JWE]

ORIGINAL: Alfred
JWE,

All info is very interesting and informative. Two variables which probably impacted upon the decision making process are:

1. steel (already mentioned by Herwin). When available, quality issues, cost from suppliers.

2. tender costs. Variability between different shipyard firms, ability to be met within allocated military budget within a specific fiscal year.

Alfred

Two excellent points Alfred; and very well taken.

Yes I did consider materials (steel) availability, even more so than in the cap ship example. I believe there was sufficient mild steel production to support more of the plan DDs - I'll explain why in just a sec.

Japan had a serious dietary infarction when it came to the specialty steels: capital warship grade chrome-molys and corrosion resistant, turbine grade, chrome-vanadiums. So it was more of a barf to the engineering plant/armor kinda thing than to hull construction material per se (up to a point). Reason I believe they had a sufficiency, is because 1944 hit the high point in ships constructed; many hundreds more than '43. We're only talking 15, 20 more DDs, so the only issues would be with steel for the high speed turbine blades and the rolling mills for more 3.9" barrels. Of course, the systems guys will have to pump out more stuff, but ... still looks like 'most' things were available in sufficient quantity in the time frame under consideration.

Cost; woof!!! Wartime does nasty things to accounting. You can figure out direct cost, and sometimes indirect cost, but GS&A disappears. Then there's the subsidies for direct and indirect cost. And all the govt has to do is print more money, so there's the sidebar inflation to the calculation results, but they don't take the vicious consumer level cuts (and consequent savings) into account. Yeah, ok, Japan spent 30% (and more, and more) of GNP for the military (mostly the Navy), but all that stuff is "paper" money. If the folks at home are eating window-sill greens and grass clippings, and buying nothing, the actual push is way more than 30% but it is a useless parameter. One may plan, print and spend as many Tojo-bucks as one wishes (given the capability of the resource/materials base) and the ONLY limitation is the consumer section's willingness to accept rendered down racoon fat as butter. It's a real witch when ya talk about a planned economy.

Love to get deeper, but gotta go. Have dinner, smiling and dialing, for a bunch of people. Ciao. John

[GaryChildress]

ORIGINAL: JWE

Just for fun, here’s the actual construction scheds (keel-to-launch) for the only four yards capable of building a capital ship. A BB or large CV (Taiho/’Kaku) required a 300m slipway (only 3 in existence). A CA or Unryu type CV required a 225-250m slipway (only 3 in existence by end of war). They were actually utilized pretty well … hull # 111 and Shinano seem to be the only major abortions.

I'm confused. You say a BB or large CV Taiho required a 300m slipway, of which only 3 were in existence. Yet, on your chart I see 4 slipways being utilized between building Yamato, Musashi, Shinano & Taiho. Apparently there must have been 4 slipways of 300m or so. It looks like Yokosuka NSY #1, Kure NSY #1, Mitsubishi-Nagasaki #1 and Kawasaki-Kobe #1 were all capable of delivering large capital ships. [&:]

[JWE]

ORIGINAL: Gary Childress
I'm confused. You say a BB or large CV Taiho required a 300m slipway, of which only 3 were in existence. Yet, on your chart I see 4 slipways being utilized between building Yamato, Musashi, Shinano & Taiho. Apparently there must have been 4 slipways of 300m or so. It looks like Yokosuka NSY #1, Kure NSY #1, Mitsubishi-Nagasaki #1 and Kawasaki-Kobe #1 were all capable of delivering large capital ships. [&:]

Kawasaki Kobe #1 was surveyed immediately post war as 250m - hard - 1.2% grade. Difficult to say whether the survey paradigm was perps or not. Might not matter much since Taiho was 238m on perps and 253m on lines. Overhang don't matter much on a hard.

But yeah, Taiho wanted a more righteous space. She got scarred by that stupid Hiyo/Junyo fiasco and had to be shoehorned into Kobe ... life was not good for the Great Phoenix.

[JWE]

ORIGINAL: Gary Childress
It appears some ships were laid down with several months gap in between use of the slipway. I wonder if it is not plausible that Japan could have made better use of the slips by starting projects sooner after completed ones. It looks like Kobe #1 was by far the most efficiently used slip between 1938 - 1945.

No, it is not plausible. It was not physically possible. In addition to the nonexistence of sufficient fitting space, there was the issue of no money. Nonexistence of sufficient fitting space means nonexistence of sufficient fitting space, no matter how many or how big the slipways are. It means launched, unfinished hulls are just sitting, anchored in the Bay, deteriorating. Pre-war, when money meant something, no money means no money. It doesn't mean just increase the budget, it means no money.

Kobe had holes too. Hiyo was a civilian ship and did not impact any Naval space utilization till after purchase and converson.

[GaryChildress]

ORIGINAL: JWE

ORIGINAL: Gary Childress
It appears some ships were laid down with several months gap in between use of the slipway. I wonder if it is not plausible that Japan could have made better use of the slips by starting projects sooner after completed ones. It looks like Kobe #1 was by far the most efficiently used slip between 1938 - 1945.

No, it is not plausible. It was not physically possible. In addition to the nonexistence of sufficient fitting space, there was the issue of no money. Nonexistence of sufficient fitting space means nonexistence of sufficient fitting space, no matter how many or how big the slipways are. It means launched, unfinished hulls are just sitting, anchored in the Bay, deteriorating. Pre-war, when money meant something, no money means no money. It doesn't mean just increase the budget, it means no money.

Kobe had holes too. Hiyo was a civilian ship and did not impact any Naval space utilization till after purchase and converson.

Do we know that Japan lacked sufficient fitting space?

It doesn't look like Kobe had too much in the way of holes. Nor did Yokkosuka #1 in the late 30s from the looks of it. Below is a schematic I made based upon the dates I found for being laid down and launch of ships at Kobe. According to http://www.warshipsww2.eu/staty.php?language=E Kobe was pretty efficient as far as time spent with the slip empty. Some ships were started only weeks after the former was launched. [X(]

[JWE]

ORIGINAL: Gary Childress
Do we know that Japan lacked sufficient fitting space?

Yes.

It doesn't look like Kobe had too much in the way of holes. Nor did Yokkosuka #1 in the late 30s from the looks of it. Below is a schematic I made based upon the dates I found for being laid down and launch of ships at Kobe. According to http://www.warshipsww2.eu/staty.php?language=E Kobe was pretty efficient as far as time spent with the slip empty. Some ships were started only weeks after the former was launched. [X(]

That's because Junyo is there as a naval vessel. It was not, really. It was started (and darn near finished) as a civilian passenger ship. Kobe was lucky in only having one way used for larger naval vessels. Even so they were size staggered; Mizuho finished off like an auxiliary, not like a warship. It could go the civilian side for fitting. Kobe could not have done sequential large warships. Large warships spend more time fitting than they do building.

Sorry, but really don't want to get into 'what if' things in this thread.

[herwin]

ORIGINAL: JWE
Large warships spend more time fitting than they do building.

They ran into that problem in the UK as war damage piled up.

[GaryChildress]

OK. I did a little research into Japanese ship production based upon the following dates for all major warships constructed between 1930 - 1945: Laid down, launched, commissioned. This is essentially the real life build queue for the IJN.

Red bars are the time the ships spent in the construction slips. Yello is the length of time between launch and commissioning.

My source was: http://www.warshipsww2.eu/staty.php?language=E&period=2

[EDIT: note this chart is not organized by individual construction slips. Each row represents a single ship.]

[Shark7]

Wow. 10 years for the carrier conversions. No wonder it was such a mess in 'hurry up mode'.

[JWE]

ORIGINAL: Shark7
Wow. 10 years for the carrier conversions. No wonder it was such a mess in 'hurry up mode'.

LoL [:D] But not really. For example, Shoho was laid down as Tsurugisaki 12/03/34, launched 06/01/35, delivered 01/15/39 (still quite a while).

Served for 2 years as Tsurugisaki. Began conversion 07/12/41, delivered 11/30/41 as a Special Type Ship, entered fleet service as CVL 12/22/41.

Really have to be careful with internet dates. One site makes a typo and everybody just copy-pastes and then you get bad info becoming gospel because "everybody" says so. [;)]

[DuckofTindalos]

Are you implying that the Internet is a less than perfect source of information? Say it ain't so!

[Historiker]

Really have to be careful with internet dates. One site makes a typo and everybody just copy-pastes and then you get bad info becoming gospel because "everybody" says so.

Its the same about books...

Maybe you've already seen it yourself, how the data about Japanese ships (and to some extend German ships) differ...
One copies from another, then the data is converted from english to metric and rounded, later converted back...
Then some don't know that the Japs sometimes tended to call their guns a different size but not always...

So the Yamato ends up with 45,7cm, the Nagato with 40,6cm, the Bismarck with 381mm...
Its the same about tonnage...

[Shark7]

ORIGINAL: JWE

ORIGINAL: Shark7
Wow. 10 years for the carrier conversions. No wonder it was such a mess in 'hurry up mode'.

LoL [:D] But not really. For example, Shoho was laid down as Tsurugisaki 12/03/34, launched 06/01/35, delivered 01/15/39 (still quite a while).

Served for 2 years as Tsurugisaki. Began conversion 07/12/41, delivered 11/30/41 as a Special Type Ship, entered fleet service as CVL 12/22/41.

Really have to be careful with internet dates. One site makes a typo and everybody just copy-pastes and then you get bad info becoming gospel because "everybody" says so. [;)]

So basically, it served for 2 years as a merchant/tanker, then went back into the docks to become a carrier. That better explains the long time between launch and commission as a carrier.

Would better organization (rather than additional docks/slips) have done anything to streamline the process pre-war? Since we know there is only finite space, not enough fitting docks, and at best a 20% expandability it seems the best way to get the most bang for buck would be to really focus on the management side of the yards and coming up with a production schedule that makes best utilization of the available facilities. From the sounds of it, the Naval Command had a bigger appetite than their facilites could support.

[Shark7]

ORIGINAL: Terminus

Are you implying that the Internet is a less than perfect source of information? Say it ain't so!

But... but... That's not what's posted on the internet!!!! [:'(]