Hearts of Iron IV - Development Diary 5 - Production Lines

[Big Nev]

Well efficiency curves make little to no sense for capital ships to start with since I don't think a single nation built two of them in serial ( one after the other ) without pretty major modifications to the design.

To be honest assembly lines at all is not compatible with capital ship construction.

100% correct. I really couldn’t agree with this more.

I can only think of the Queen Elizabeths as a BB class that had more than four and none of them were built “consecutively”. Malaya was laid down after Queen Elizabeth I was launched but she was built in a different yard so still doesn’t count. The only CV class that I know of with more than two or three are, of course, the Essex’s.

And the Essex class is a very important case-in-point. They were laid down, individually to start with, then in pairs several months apart. Of those completed in time to see service in WWII, they took about 20 months from being laid-down to being commissioned.

So… Even for the largest “production run” in history of large capital ship (running from Apr 41 to Nov 44) there was no appreciable reduction in build time from first to last.

Essex (CV9) Apr 41 to Dec 42 = 20 months
Bon Homme Richard (CV31) Feb 43 to Nov 44 = 21 months

(someone correct me if I’m wrong, but there were fourteen in this class which saw service. I’m not counting the later ones as many conversions were begun &/or production switched as it became obvious that they wouldn’t be needed. I’m also considering the long-hulled versions are essentially identical to the first batch)

It must also be remembered that the Essex class was designed to be quick and easy to build with lots of flat & straight bits where other ships had complex & graceful curves. The Essex’s only had curves where they needed them. Mass production techniques were NOT used other than for their equipment. The large pieces affected being their engines and the dual 5” DP turrets being used on just about every US ship at that time.

(I think they had a factory or three just churning these out and were actually looking for things to put them all on. I mean, cramming 8 dual 5” turrets on a 6,000 ton over-grown destroyer. Seriously?!)

So… IMHO, the only way to reduce capital ship construction is by learning to incorporate the lessons learned from previous capital ship construction by class.

So if you build a bunch of BBs/CVs, they all take the same length of time to build. But your next batch, which could be of a higher tech level (I guess they’d have to be, to be a different class) take a little less time.




Note : It should also be remembered that the Essex’s were very expensive in terms of money for a ship of their weight & complexity due to the materials of which they were made. If money is going to count for anything that is.

 

[Dalwin]

Again considering that we aren't going to be modelling each shipyard separately, I am not sure that the efficiency curve can be ruled out completely. There were several capital ships built to certain classes, though I am not sure on the construction years for some of these. They may well have been built before 1936. Lke the 5 ships in the "R" class, Ramilles etc., I think they were pre-war. But how about the KG5 class?

When not talking about capitals, some were definitely assembly line. Most notable, of course, being the liberty ships. Some destroyers were as well.

This brings up something that I don't see alluded to very often on these forums, which is one of the underlying reasons why so many Shermans were built. It is not as simple as the US not being able to retool to a better tank earlier. One of the reasons they kept knocking them out was that they fit conveniently onto Liberty ships.

On general principal I agree about efficiency curves for naval construction, though. The whole production line system is not a very good fit for naval units. However, the gains for the game from having production lines for ground and air outweigh the awkwardness to naval, in my opinion. There are also significant gains to having naval production on a separate set of factories from the rest.

 

[wolf1455]

I like, good work.

 

[misterbean]

Is that why the US build them with wooden launch decks instead of armoured deck? Just to speed things up?

 

[Dalwin]

Is that why the US build them with wooden launch decks instead of armoured deck? Just to speed things up?

Was only talking about Liberty ships which were mass produced merchant ships, more than 1,000 built during the war. I'm not sure where launch decks fits into that.

EDIT: according to one history site it was 2,750 Liberty ships built between 1941 and 1945.

 

[tommylotto]

This brings up something that I don't see alluded to very often on these forums, which is one of the underlying reasons why so many Shermans were built. It is not as simple as the US not being able to retool to a better tank earlier. One of the reasons they kept knocking them out was that they fit conveniently onto Liberty ships.

Yes, I was thinking about this too. That short barrel 75 was not much longer than the chassis itself and would travel well. Whereas a longer barrel like the Firefly would be a bitch to efficiently store in a cargo hold, and, I imagine, considerably fewer would fit in the same space. Not much of an issue if you just have to hop the channel, but a major concern if you have to ship them over oceans all over the world to allies everywhere.

 

[misterbean]

Was only talking about Liberty ships which were mass produced merchant ships, more than 1,000 built during the war. I'm not sure where launch decks fits into that.

EDIT: according to one history site it was 2,750 Liberty ships built between 1941 and 1945.

I was referring to US carriers and getting them done ASAP. Sorry about the confusion.

 

[Praetori]

Yes, I was thinking about this too. That short barrel 75 was not much longer than the chassis itself and would travel well. Whereas a longer barrel like the Firefly would be a bitch to efficiently store in a cargo hold, and, I imagine, considerably fewer would fit in the same space. Not much of an issue if you just have to hop the channel, but a major concern if you have to ship them over oceans all over the world to allies everywhere.

The Firefly conversion adding the 17-pounder was a British enterprise and since no reliable HE rounds for the 17-pounder were available when mass production in the states ramped up and the US still regarded the Shermans primary role as infantry support rather than tank-vs-tank the choice to no retool the american tank ordnance line isn't that strange (remember it wasn't just the tanks and the guns but also vast quantities of munitions).

 

[Big Nev]

Is that why the US build them with wooden launch decks instead of armoured deck? Just to speed things up?

No. It was US doctrine to have the armoured deck at hanger level to meet stability requirements that the weight of a heavily armoured flight deck (many meters higher) would not meet.

They still built the carriers with steel flight decks, just not armoured. Although, in the case of the Essex’s, I’m pretty sure the flight deck was made of a type of steel (Special Treatment Steel) more commonly used as armour. Use of this Chrome-Nickel steel as structural steel is what made them so expensive. IIRC, one of the class had a bomb hole in her deck patched by welding a double thickness of structural steel plates over it because the correct grade of steel (STS) wasn’t available where she was being patched-up.

This STS deck didn’t protect the ship much at all really, but it did limit the damage the deck suffered to the locality of a hit. An ordinary structural steel (or steel supported wooden) deck would get whole sections completely blown away by bombs, but these only got holed & could be patched. Not as good as the Brit’ carriers where bombs & kamikaze hits frequently bounced off (requiring little more than a sweeping brush & some quick-drying cement to fill the dent) but still, better than their predecessors.

An interesting question would be… how did the Brit’s maintain a ships design stability with so much heavy steel so high-up?

The aircraft limitation was mostly to do with not parking/storing on-deck, so I don't think that's it.

 

[Porkman]

No. It was US doctrine to have the armoured deck at hanger level to meet stability requirements that the weight of a heavily armoured flight deck (many meters higher) would not meet.

They still built the carriers with steel flight decks, just not armoured. Although, in the case of the Essex’s, I’m pretty sure the flight deck was made of a type of steel (Special Treatment Steel) more commonly used as armour. Use of this Chrome-Nickel steel as structural steel is what made them so expensive. IIRC, one of the class had a bomb hole in her deck patched by welding a double thickness of structural steel plates over it because the correct grade of steel (STS) wasn’t available where she was being patched-up.

This STS deck didn’t protect the ship much at all really, but it did limit the damage the deck suffered to the locality of a hit. An ordinary structural steel (or steel supported wooden) deck would get whole sections completely blown away by bombs, but these only got holed & could be patched. Not as good as the Brit’ carriers where bombs & kamikaze hits frequently bounced off (requiring little more than a sweeping brush & some quick-drying cement to fill the dent) but still, better than their predecessors.

An interesting question would be… how did the Brit’s maintain a ships design stability with so much heavy steel so high-up?

The aircraft limitation was mostly to do with not parking/storing on-deck, so I don't think that's it.

The Brits didn't maintain stability.

The British are to carriers what the Japanese are to tanks.

 

[Big Nev]

The Brits didn't maintain stability.

The British are to carriers what the Japanese are to tanks.

HA!

Yeah. That’s why every US carrier designed since the war followed the British pattern by moving the armour up to flight-deck level.

Because the Brit' carriers were crap

See my earlier comment about the sweeping brush & quick-drying cement. It seems someone in the USN did a cost-benefit analysis and concluded that the broom & a couple of buckets of concrete works out cheaper than three months in dock for repairs.

 

[misterbean]

An interesting question would be… how did the Brit’s maintain a ships design stability with so much heavy steel so high-up?

The aircraft limitation was mostly to do with not parking/storing on-deck, so I don't think that's it.

I believe it had something to do with the island and the weight distribution in the fuel tanks, among other things.

 

[Marcus]

Am I the only one that is really excited about sub warfare now that as Germany (or even Italy!!!!) I can disrupt the UKs war machine (which was always tricky up to now, no effect for a long time and complete and total industrial collapse only after years of effort).

Is anyone able to say anything sensible about Soviet vulnerability to resource disruption?

 

[Big Nev]

Err…

Has sub warfare even been mentioned in a DD yet?

Did I miss (or forget) something? I know it wouldn’t be the first time.

Soviet vulnerability to resource disruption. Hmm…

Somebody educate me. What resources (apart from officers) were the Sov’s so short of that could have become as critical as oil, Tungsten & rubber (plus a few others) were to Germany?

 

[Joppos]

I reallyreallyreally hope we'll be able to disrupt both resources/lend-lease/equipment trades through naval warfare in any meaningful fashion. Instead of just sinking convoy boats themselves.

 

[Alex_brunius]

Err…

Has sub warfare even been mentioned in a DD yet?

Did I miss (or forget) something? I know it wouldn’t be the first time.

While sub warfare was not mentioned directly the industrial impacts of it should be more immediate and severe thanks to the changes to stockpiles and the resource system we can read about in this DD:

Moving on to the actual means of Production, Factories no longer need Metal/Energy/Rare Materials to run. Requiring the player to gather several different types of resources in order to manage factories did not necessarily add anything interesting to the mix. Being short on any of them had the same effect no matter what you were lacking (your Industrial Capacity would shrink) and it didn't entirely make sense that you couldn't build things like Militia if you didn't have access to Rare Materials.

We have simplified the inputs to "Raw materials" which factories use to run. Raw materials act as a limit on your total Industrial Capacity. However that is not the whole Production story. Equipment also has a Strategic Resource cost, without which it takes much longer to produce. Strategic Resources are not accumulated in pools. Instead, they represent the potential flow of resources into your factories. For example if you have 10 Iron you can be building stuff that costs up to 10 Iron at any one time.

 

[Big Nev]

I reallyreallyreally hope we'll be able to disrupt both resources/lend-lease/equipment trades through naval warfare in any meaningful fashion. Instead of just sinking convoy boats themselves.

If you mean sinking the cargo they are carrying at the same time as the ship then yes, absolutely 100% with you on this.

You can park half your fleet next to Midway and the garrison will never run out of supplies until your enemy has completely run out of convoy ships.

PDS, please fix the system that makes this possible.

 

[podcat]

Err…

Has sub warfare even been mentioned in a DD yet?

Did I miss (or forget) something? I know it wouldn’t be the first time.

Soviet vulnerability to resource disruption. Hmm…

Somebody educate me. What resources (apart from officers) were the Sov’s so short of that could have become as critical as oil, Tungsten & rubber (plus a few others) were to Germany?

I dont think the soviets had any issues like that, disrupting them would be targeting lend lease and such

 

[PlacidDragon]

Somebody educate me. What resources (apart from officers) were the Sov’s so short of that could have become as critical as oil, Tungsten & rubber (plus a few others) were to Germany?

I dont think the Soviets were short on anything in terms of raw materials. The Russians have usually been quite a bit behind the west in technological development, so they didnt start taking advantage of many of their resources until fairly late (compared to a western nation). And as such, they had a stupendous abundance of anything you could possibly think of more or less

The only thing i could possibly think of that could be a problem for the Soviets were if the Germans managed to take the Caucasus, with its rich oil fields in the Baku region. That would likely have given the Soviets trouble, at least in the short run (and possibly the long run too).

 

[sgt.stickybomb]

The Brits didn't maintain stability.

The British are to carriers what the Japanese are to tanks.

true, Brits invented tanks, while the japs invented carriers