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HoI4 Dev Diary - Fuel Review and Motorized Artillery

Hello and welcome back for the first dev diary of 2019! Today we will update you on the state of fuel as well as show you a little something many people have wanted for a long time.

Changes and Updates to the Fuel Implementation

When the game launched, oil was used as other resources for the purpose of production. This was an abstraction done for fuel consuming equipment. We have removed this abstraction but are still using a simplified version of what happens in the real world. Oil refining was and is not as simple as simply processing it into a multipurpose “fuel,” but we felt that this simplification was necessary for gameplay and consistency of depth of detail.

We have added fuel as a resource to the top bar. With this UI element we convey a few bits of information. The numbers show the amount of time you have before being full or dry. Here the number is green and indicates that the stockpile will be full in 361 days. The numbers will become red if fuel is being lost. The green bar indicates the state of the stockpile, showing how full it is. The arrows indicate that fuel is currently being gained.

top bar fuel.png


Oil is still traded as it was previously but is no longer used in any production. Instead, excess oil is converted to fuel at an hourly rate. The trade UI has had some slight updates to take this into account. What was formerly the “production” category is now “need.” Oil now has special subcategories of this section. Active need and potential need are now represented with “A” and “P,” explained more thoroughly in tooltips. This helps give the player an understanding of how much oil needs to be traded if they wish to try and cover their current fuel needs with a constant supply from oil refining.

fuel trade ui DD.png


Refineries have also been changed from giving Oil resources to giving hourly fuel. This both makes more sense from a historical perspective and makes it easier to control how much resource is produced by refineries. Previously, tech increases could only allow for a minimum increase of a single unit of oil. This gives developers and modders much better granular control over the output of a synthetic refinery.

For countries that will not have enough fuel production during wartime to meet their needs, developing a healthy stockpile is an option. Most nations will not start with a large stockpile capacity. Stockpile potential will be reduced by economy laws for many nations. Also, increasing stockpile capacity requires some investment, and will take space away from industry through the production of silo facilities. Japan is a good example of a nation that may run into a situation during the war when their usage far outstrips their potential fuel gain, so they will need to have a decent reserve of fuel if they want to fight the US in the Pacific.

fuel_1.jpg


To help understand what is going on with your fuel stockpile and to manage distribution when fuel has become tight, we have added fuel as a special section to the logistics tab. This includes a breakdown of usage by military branch of the military and the ability to control who gets priority for fuel distribution. A special variant of the stockpile menu used for other equipment shows a breakdown of fuel consumption by day, month, and year as well as a breakdown of the state of the stockpile over time.

fuel stockpile menu.png


The logistics support company has also been changed and will help with keeping your armor fuel usage more manageable.

image (1).png



Motorized Artillery Units

When Hearts of iron 4 was released, it featured a very large number of possible battalion types that you could use to design your divisions. However, there were a few unit types that were pointedly absent. For example, if you wanted to make a motorized infantry division that was a faster version of your regular infantry division with line artillery - you couldn’t, unless you were okay with slower speed.

Part of the reason for this was the feeling that a motorized artillery unit didn’t have enough of a drawback to be a meaningful choice - it would just be better than regular artillery, and the added cost of a handful of trucks was not a major issue if you were building trucks anyway.

mot_arty_1.jpg


With the addition of fuel, that has changed. Now it is a long-term decision to motorize more of your force, and it requires more planning as your army suffers increasing penalties if you can’t meet fuel demands. So we decided to add motorized artillery units in regular artillery, rocket artillery, anti-air and anti-tank flavors. They are, by and large, identical in firepower to their horse-drawn versions but require 50 trucks each, have a roughly 50% bigger supply footprint and, of course, require fuel to run properly.

mot_arty_2.jpg


No special tech is required to unlock motorized artillery; having motorized equipment and the respective artillery type researched also unlocks the motorized unit.

That’s all for today, tune in next week when we talk about changes to research and show off the new naval tech tree!
 
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If oil is not used for production anymore, having excess oil means that you get positive fuel gain from oil recourse or you can sell the oil if you wish? What about having negative oil? It gives negative fuel gain from oil resource?
No you do not get negative directly from not having enough of the resource. What resource you have gives you fuel. This fuel gets used. If you produce less than you use your stockpile will shrink due to usage. IF your stockpile runs dry there will be dire consequences to unit performance.
 
Cheers for the DD Archangel and the extra info Podcat :). Great news as well - fuel's looking appropriately hi-octane, and those motorised artillery/AT/AA sound tops (up until now, I'd been building Light SPART, SPAA and SPAT as proxies, but it wasn't the same!)

For a naval-related pic, it's hard to go past one of a tanker - here's SS Ohio, one of the more famous tankers of the war, struggling into the Grand Harbour at Valetta, Malta, at the end of Operation Pedestal - look closely and you'll see she's got a ship on either side helping keep her afloat! One of the few oil tankers in the war that has had books written about them :cool:.

SS-Ohio_supported.jpg


the new naval tech tree!

Bring on next week :D.
 
The UK should become especially vulnerable to having it's oil supply cut off now, IF subs are viable. And the US is going to have CIC to burn from trade.
Actually, I see the opposite being the case for US trade and to a lesser extent the Soviets. In the current version those two make a lot of CIC from trading oil during the critical prewar buildup period. Even in '36, countries need oil to make tanks/planes/ships. In the new version, the prewar need will only be for training and stockpiling.

I think both the US and Soviets take a big economic hit overall from the change.
 
Secondly, please have a look at the 50% bigger supply footprint. It is not realistic. Motorisation is a manpower saver*, as truck drawn heavy equipment requires fewer men to look after a small number of trucks compared to hundreds of horses, and the fodder for those horses is much more bulky than the non-fuel parts needed to keep the trucks running. Historically, some armies motorised some parts of leg infantry divisions. There is no rationale to do that in game as it would stand under this proposal, however if the supply footprint was reduced at the cost of needing trucks and fuel it's an interesting trade off decision for players to make.

* Examples:
1. In a Japanese Infantry division's transport regiment, a wagon company with 350 men could transport 62.5 tons while a motorised company with 150 men & 50 1.5t trucks could transport 75 tons. Then there's also the matter of both wagons & trucks requiring roads and the trucks can travel much further per day acting as an additional multiplier in the amount of supplies they can bring forward.
2. A German 1939 motorised infantry division had 16,445 men vs a 1st wave infantry division of 17,734. With identical structures, except for very minor differences, the motorised division which has to provide drivers for the trucks to transport all the infantrymen still has 1,300 fewer men. Also, the 1st wave division isn't fully horse drawn requiring 615 trucks (1,687 in the motorised division) and 4,842 horses. So, in rough terms, the extra 1,000 trucks in the motorised division transported all the infantrymen (say 400-500 trucks) and did the job of 4,800 horses (500-600 trucks).

Allied planners counted on needing 700 tons of supplies total per division and day, while German divisions needed only 200-250 tons.

Guess what the main difference was? Yes the allies used mainly trucks while the Germans used mainly horses.

Food for the men is a pretty small part of the supply need in a division. 2kg food per man x 1300 less men = 2.6 tons less supplies per day.

Also for most of the year in temperate climates horses eat grass or fodder from local farmers as long as they are not all in the same place. The 2000+ vehicles in an allied division need a massive amount of fuel and spare parts, especially when you start going off-road or put combat stress on them.
 
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@podcat - now we just need to add horses to the production component and we'll be set!!!
 
Allied planners counted on needing 700 tons of supplies total per division and day, while German divisions needed only 200-250 tons.

Guess what the main difference was? Yes the allies used mainly trucks while the Germans used mainly horses.

Food for the men is a pretty small part of the supply need in a division. 2kg food per man x 1300 less men = 2.6 tons less supplies per day.

Also for most of the year in temperate climates horses eat grass or fodder from local farmers as long as they are not all in the same place. The 2000+ vehicles in an allied division need a massive amount of fuel and spare parts, especially when you start going off-road or put combat stress on them.

Comparing division numbers in 1944/45 is like comparing apples and steak.

At full strength German divisions averaged around 12,000 men while Allied divisions averaged at least 15,000. Then there's the matter of non-divisional combat units included in the Allied divisional slice. The US kept their divisions lean with large numbers of non-divisional units, but even the British had significantly higher levels of non-divisional combat troops than the Germans. With them added in the Germans increase to around 14,000 per division while the Allies are over 20,000. Then there's also the matter of the availability of replacements. The Germans were lucky to keep a division at even half strength. In comparison even though they started running short of infantry replacements, the Allied divisions were kept at almost full strength. A typical Allied divisional slice would have 3 times as many troops as a German in Europe after the summer of 1944.

Then there's also artillery ammunition. Even as far back as 2nd Alamein in 1942, Allied guns were expending large multiples of the number of artillery rounds the Germans fired. I remember one account from that battle where the Germans scraped together a bombardment to support a counter attack and the Brits didn't even realise there was an increase in the German fire. This disparity is also well accounted for in Niklas Zetterling's "Normandy 1944" so its not just a matter of difficulty in shipping supplies to Egypt - the German reserve stockpiles just didn't exist so there was no need for them to plan/try to transport additional shells that didn't exist.

Now I'm no expert on horses, but I did study the Napoleonic wars for a long time. Significant grass could only be counted on for a few months of the year, and to be kept in top condition horses should have additional types of fodder. The supply weight of a cavalry division in WW1 was huge compared to an infantry division due to the need to supply fodder for horses. The Germans were also running short of horses by 1944. Most of the divisions in western Europe had reduced mobility compared to those in the east, and a big part of that was not having the vehicles or horses to move all their heavy equipment. Many divisions only sent a mobile battlegroup to Normandy as all their other guns & troops had to stay in place. That's something not covered in HOI4 as yet - garrison troops with lower mobility and supply footprint. You also mention the need to keep horses dispersed if they're going to live off grass. When I see horses in paddocks the amount of land each one uses is huge, and dispersing them to that degree means that they can't easily be used for the daily transport of supplies, so again we're looking at needing fodder.

Then we come to the Allies operating at large distances from their production facilities in the US. They had to plan for higher than actual consumption of supplies given the lag that would ensue if calculations were out, meaning they had to amass massive depots. I remember reading about the US depots in Naples. They were so large that even though they lost a large proportion of their contents to theft, there was never a shortage to send to the front. You mentioned 2kg food per day per man. From what I can see the US allowed for 7.7lbs (3kg) per day per man in Europe - an example of over insurance.

Aren't supply and fuel now separate with supply thus representing all non-fuel supplies. Presumably the ability to move fuel through the supply chain will be limited by infrastructure & supply bottlenecks just like replacement men & equipment, so it has its own burden rather than needing to be included as part of the supply footprint. About 1/3 of US supply was POL. Now if there's no additional supply chain burden from getting fuel to units, then yes motorised units need to have fuel use included in their supply footprint, but I'm hoping the devs have not made that mistake, and I wanted to illustrate that horse drawn logistics have consequences that aren't well modelled at the moment.
 
R.L Dinardo has a very good book about Horses and the WW2 German army. You can find it at the Stackpole Military History series. At Stalingrad the German infantry divisions could not break out because they had to send their horses 200km back to find fodder. It got so bad that they had to cut ammo supply runs to move fodder into the city to feed the horses.
 
R.L Dinardo has a very good book about Horses and the WW2 German army. You can find it at the Stackpole Military History series. At Stalingrad the German infantry divisions could not break out because they had to send their horses 200km back to find fodder. It got so bad that they had to cut ammo supply runs to move fodder into the city to feed the horses.

Whereas with trucks they'd have been paralysed by fuel and spare parts issues rather than fodder issues. I'm sure that would've been comforting.
 
I wouldn't be surprised if there is going to be a lot of balancing issues related with the new fuel consumption mechanic, but I like it it makes, more sense than the current oversimplified mechanic.
 
With the addition of fuel, that has changed. Now it is a long-term decision to motorize more of your force, and it requires more planning as your army suffers increasing penalties if you can’t meet fuel demands!

Oil now has more value in this game but what are the penalties if you don't have any oil left.

I hope it's not something lame like bandwidth throttling if you exceed your cap. :D
 
Between the Ribbentrop-Molotov Pact and the invasion of the USSR. Germany received 50% of its fuels from the Soviet Union. Will this be reflected somehow with the German-Soviet trade agreement event? Germany in exchanged would sell vehicles and machines for agriculture although these don't exist in the game. A lot of German purchases were done on credit and delayed (on purpose) to deprive the USSR of resources which in turn Germany would use for its invasion eastwards.
 
Cheers for the DD Archangel and the extra info Podcat :). Great news as well - fuel's looking appropriately hi-octane, and those motorised artillery/AT/AA sound tops (up until now, I'd been building Light SPART, SPAA and SPAT as proxies, but it wasn't the same!)

For a naval-related pic, it's hard to go past one of a tanker - here's SS Ohio, one of the more famous tankers of the war, struggling into the Grand Harbour at Valetta, Malta, at the end of Operation Pedestal - look closely and you'll see she's got a ship on either side helping keep her afloat! One of the few oil tankers in the war that has had books written about them :cool:.

SS-Ohio_supported.jpg




Bring on next week :D.
(O/T) I remember when, as a teenager, I first read about the Ohio. An amazing story, I still get a lump in my throat thinking of that wonderful ship.(/O/T)

Am I the only one who's been researching and building motor rocket units to use as line artillery for my motorised infantry? I mean, this is a better solution, but there WAS a workaround before.
 
Technically, in a historical sense, yes. But what is represented in game is tank based not mech based. Both Germany and the US (not sure about others) had a wide range of Half-Track based SP-Artillery and AA (not so much on AT).

"Half-Track based SP-Artillery", do you mean something like Sd.Kfz 251/9?

13_Sbrez_Drag_251-9_left.jpg


But these are just short barrel infantry support guns in mechanized infantry battalions, not field artillery units. Sd.Kfz 251/4 is a gun-towing tractor often seen with leFH 18, but they cannot be called as "Half-Track based SP-Artillery". As far as I'm concerned all light artillery units, from the 76mm field guns or 105mm howitzers, are towed by truck/half-track/tracked vehicles, none of them is mounted on a half-track platform.

ce8f0994e679f8d2fac6cd21711f7f71.jpg
 
For countries that will not have enough fuel production during wartime to meet their needs, developing a healthy stockpile is an option. Most nations will not start with a large stockpile capacity. Stockpile potential will be reduced by economy laws for many nations. Also, increasing stockpile capacity requires some investment, and will take space away from industry through the production of silo facilities. Japan is a good example of a nation that may run into a situation during the war when their usage far outstrips their potential fuel gain, so they will need to have a decent reserve of fuel if they want to fight the US in the Pacific.

View attachment 439615

er, how do Military factories and naval factories consume/use fuel?

You havn't mentioned this anywhere.
Ok currently we had oil in production units, but that's been scrapped.

So how do factories use fuel??????????
 
er, how do Military factories and naval factories consume/use fuel?

You havn't mentioned this anywhere.
Ok currently we had oil in production units, but that's been scrapped.

So how do factories use fuel??????????

Presumably the ATA needs fuel to fly the planes to the front lines, the various companies ship goods to the factories via boat and automobile transport, the staff of the plants need to eat, sleep and move around to make the goods, the finished products are taken from the factories in multiple hops via multiple forms of transport.


Though I'm sure you can edit the files to make it "Push Button, Receive Panzer" if you like.