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HOI4 Dev Diary - Supply and Mulberry Harbors

Greetings all, and welcome to today’s dev diary on the huge supply system update coming with the Barbarossa update. Before we begin, I’ll leave a heads up that this will be the last dev diary before we break for summer, so don’t expect anything new until some time in August at the earliest.

Since we last talked about supply, a few things have changed. We found that the way truck need could take off and spike was hard to deal with and that watching out so you didn't overload individual supply hubs was a bit too intensive. We also felt that the way the mapmode worked made it very difficult to project how well supply was flowing.

The iteration we have now aims at addressing these shortcomings. It's now possible for divisions to supply from multiple hubs. Trucks are now less of a strict necessity, rather something you can assign to hubs to make sure they can project supplies further away. Finally, the mapmode has changed to better show the spread of supply as well as current status for divisions.

Supply flow

From each hub connected back to the capital, potential supply is projected outwards - adding up when overlapping. This is represented by the brighter colors below. For each province in distance that supply needs to travel from a hub, there is a reduction in the amount as some is lost. The amount depends on various factors like terrain, crossing rivers etc. The dark purple areas below are reduced to local supply only, and the highlighted red-orange areas indicate locations where there are units suffering from significant supply issues.

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In the picture above, the Ukraine/Caucasus front is mainly struggling because it is overextending before the captured rails have been converted, so a lot of the rail network there is not operating. When a railway is taken over there is a longer cooldown when it gets converted for use by you (representing a combination of repaired damage, gauge-alteration, and general maintenance), and without connected hubs supply won’t flow.

How much you can output from each hub depends on the level of railways leading back to the supply capital, and the total max there depends on your industrial base (so Luxemburg can not feed as many as soviet union, for example).

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Here, the clock indicates rails that are not yet converted, and the hub icons with red crosses indicate that they do not connect back to your network.

Motorization

To increase the range of a hub (perhaps to help supply the front above better) you can choose to improve the motorization level. The horse icon on the right indicates no motorized supply from the node, but you can opt to toggle it to a higher state of motorization. Be careful, as this will cost you trucks which are taken from the stockpile.

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It is also possible to set the motorization level on an army, in which case it will automatically toggle on motorization for hubs that it uses without requiring further interaction from the player.

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There are also some other options on a hub. The star icon lets you move your supply capital to a new location, provided that you have sufficient surrender progress. This lets you get around issues where your capital ends up cut off or surrounded, but also comes with a period of bad supply as the new location is prepared.

The blue flag next to it lets you control allied access to the node. This can be a great way to flag to an AI that you do not want them on your front, or to stop them from joining a tight landing situation.

The rail icon lets you quickly switch to construction mode and extend rails from there while the green plus will automatically queue up construction for rails to combat any bottlenecks your node may suffer from back towards the capital. The chevron icon lets you prioritize train allocation if you are running low.


Floating Harbors

As part of No Step Back, we’re introducing a new dimension to naval invasions. Floating, or ‘Mulberry’ harbors can now be constructed once the appropriate research has been completed.

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These weighty and expensive pieces of infrastructure (don’t look too close at the numbers above hehe) aren’t intended for every-day landings, but are instead intended to represent the equipment used in large-scale operations such as the Battle of Normandy.

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Naval invasions utilizing a floating harbor will be represented by harbor apparatus placed parallel province targeted by the invasion, and will immediately create a stocked supply hub at their location:

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Used carefully, one or more mulberry harbors can keep a sizable invading force supplied without requiring the immediate capture of an important enemy harbor. Of course, harbors should remain amongst the first targets of any successful invasion, and the supply hubs created by a floating harbor will be temporary; lasting a matter of weeks or months, depending on the strength of enemy air superiority and other factors.

Of course, there is yet more to cover regarding supply, and we'll have another diary on this subject in the future, but I hope you like what you've seen so far and we’ll be seeing you again after summer!

Oh, and one last thing - one of the new loading screens for NSB is this awesome Polish cavalry, so we figured we should share it as a summer wallpaper for you (fear not, there will be a soviet one eventually!)
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The vision behind the painting was to present a more historically accurate depiction of the Charge at Krojanty. This was an engagement in the opening days of WW2, where the elite Polish cavalry surprised a German infantry unit at rest, charged before it could prepare for defense, and dispersed it. They later withdrew when faced with German armored cars.

This battle is famous because it started the, often officially repeated, ahistorical view of Polish cavalry charging German tanks and we wanted to try and make something more accurate (ignore the backdrop. we couldn't resist an epic sunrise on a field, but I hope the feel is there).

We have attached 3 different aspect ration wallpapers for you, and we can't let this opportunity go without a shoutout to @CreamGene our talented 2D artist responsible for this artwork.
 

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Hmmmm.... maybe a "quick & dirty" abstraction would be to remove factories based on the military size.

Something like ...

IF # of Divisions > 50 disable 1 MIL and 1 CIV
IF # of Divisions > 100 disable 2 MIL and 2 CIV
IF # of Divisions > 150 disable 3 MIL and 3 CIV
etc, etc.
Done by divisions it wouldn't leave any scope for building "light footstep" divisions with low supply requirements, but I'd think you could do it on division total supply load.

I actually agree that it should be present, but unlike fuel transportation so is it a major balance change that needs a lot of work to get right.
Such as might be done in a major update that focusses on supply and logistics, for example? ;)

Can you rework the "No supply for AI" into a Priority system. So you could say: Prioritise supply for myself and/or ally #1 and then less people further down the priority list. That way minors can still say that their units get priority without preventing the AI from doing anything on their front. Also give the AI the insentive to prioritise players over other AIs on their soil (say you play USA and on d-day you don't have supply in France because the AI again floods your little foothold with units.
Even better would be some sort of system of "sectors" so that allies would assign units as expeditionary forces to enter specific zones. Maybe just the ability to "Request Expeditionary Units" by highlighting specific divisions? Then, divisions sent to a specific front could be incorporated into your own plans, ideally while fulfilling the ally's AI quota for that front.

That reminds me, horses aren't free either. Granted a "horsepower" resource is ridiculous, but the horse heavy german infantry divisions required a lot of extra feed. 10-15% of the divisional daily supply tonnage requirement went to feed horses alone.
So horse drawn logistic support, while not requiring fuel, should probably have a supply tax well in excess of the truck borne element.
Maybe they should take "Support Equipment" and manpower? Manpower for logistics, as discussed already, would be a major improvement (I currently reduce conscription percentages in Waltzing Matilda to allow for "logisitics train manpower", but explicit manpower for rails, supply bases and convoys would be even better).

They had a handful of torpedo boats as well, and had a crack at sending U-boats into the channel. They had some luck, but by this stage the Allies' strength on the sea and in the air meant they had a pretty hard time of it. Germany also used aerial mining, which took a toll, as well as some more exotic weapons like explosive motorboats and human torpeodes.
Several Kriegsmarine units from the French Atlantic coast tried to interfere, but several Strike Wings (with Beaufighter TFXs, mainly) that had been interdicting the conoys along the North Sea coast of Norway were relocated to Cornwall to attack anything trying such a move. These had munitions options including AP rockets, which could sink U-boats if they were caught near the surface.
 
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Maybe just the ability to "Request Expeditionary Units" by highlighting specific divisions?
That. Otherwise they stay home.
 
I think the ideal solution would be to catalog the various rail gauges worldwide, assign a unique value to each, and calculate a binary cost for converting railroads based on whether a local gauge is different from your national gauge.

If you're fighting a civil war, presumably the railroads you're fighting over are all the same gauge and can be quickly integrated into your network; if you're invading the Soviet Union, integrating the conquered railroads will take longer.

some nations use track gauges that are so different to standard gauge that transhipping to a train on a smaller/bigger gauge would just be easier. The Germans and the Soviets lucked out that the difference was just a few inches, once the track gauge difference is measured in feet then the cost/time to not just regauge the rails but also the rebuild tunnels, bridges, and possibly earthworks wider and taller just becomes too great.
 
The people on this board are a small, highly motivated subset of the community.

never doubt that a small and highly committed group of people can change the world, It's the only thing that ever does!!
 
I don't know history of Reichsbahn at all, but for some reason during WW2 Germans decided to change gauge of railways track in occupied areas of Russia rather than create bogie-change stations and assets. IMO it was a stupid decision - it looks much easier to me to create 5-10 stations way behind front lines and change bogies there rather than re-lay thousands of kilometres of rail track in bad weather (plus you get to use all captured rail transport without alterations). Maybe someone who is more knowledgeable on this can comment why Germans went this way and not the other.

Bogie changes require the rolling stock used to be set up for it, (having jacking points in the right place on every waggon) and changing the gauge of steam locomotives is a 'send it back to the works' sort of a job. The Germans planned to capture much more soviet locomotives and rolling stock than they did, and also ran some lines as russian gauge lines because the loss of capacity of taking those lines out of use for regauging would have been crippling to their current supply situation.
 
I'm looking forward to it, but still mad about the fact Finland doesn't get a focus tree in a DLC focused on the eastern front (when they actually participated in the eastern front in the Continuation War), but certain other countries do, who will only be ran for achievements then abandoned.
 
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Regarding the Tank Designer ...

Wonder how they will classify the Panther chassis. As a "medium" or "heavy"?
For those who are not aware ...
Tiger I ............ 54 tonnes
Panther ........... 44.8 tonnes
T-34 .................26.5 tonnes
Sherman .........30 to 38 tonnes

Will this lead to the recently requested mix of different tank classes in the same unit?

Or will we get a watered down Panther shoehorned into the medium class?

I do love the Soviet system, which dumbed it down for even us simple folks.
Above 40 tonnes you are a Heavy Tank. Below 20 tonnes, you are a Light Tank.
 
Regarding the Tank Designer ...

Wonder how they will classify the Panther chassis. As a "medium" or "heavy"?
For those who are not aware ...
Tiger I ............ 54 tonnes
Panther ........... 44.8 tonnes
T-34 .................26.5 tonnes
Sherman .........30 to 38 tonnes

Will this lead to the recently requested mix of different tank classes in the same unit?

Or will we get a watered down Panther shoehorned into the medium class?

I do love the Soviet system, which dumbed it down for even us simple folks.
Above 40 tonnes you are a Heavy Tank. Below 20 tonnes, you are a Light Tank.
Judging by the tank designer dev diary, the Panther is "unlocked" by researching the basic 3 "1943" or advanced medium tank techs. I understand your point, but the original panther as designed by MAN was not as up-armored as the production version. It was supposed to be ~35 tons, but of course you-know-who had to demand more armor. The armament and speed seem appropriate for medium classification...the actual production Panther could just be a +10 armored variant of the vanilla unlocked advanced medium. Reliability would be reduced, as seems historically accurate, at least for the initial production variant.
 
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For what it's worth I count the Panther as a heavy tank in Waltzing Matilda, because it was used like a heavy tank (single batallions mixed in with medium tanks in a division) and it cost (in various ways) as a heavy tank. As a result I am able to give the Panther some really hefty punch, also with reasonable speed, but at a steep cost - which seems reasonably representative of the history, to me.
 
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Oh, and one last thing - one of the new loading screens for NSB is this awesome Polish cavalry, so we figured we should share it as a summer wallpaper for you (fear not, there will be a soviet one eventually!)
View attachment 735832
The vision behind the painting was to present a more historically accurate depiction of the Charge at Krojanty. This was an engagement in the opening days of WW2, where the elite Polish cavalry surprised a German infantry unit at rest, charged before it could prepare for defense, and dispersed it. They later withdrew when faced with German armored cars.

This battle is famous because it started the, often officially repeated, ahistorical view of Polish cavalry charging German tanks and we wanted to try and make something more accurate (ignore the backdrop. we couldn't resist an epic sunrise on a field, but I hope the feel is there).

We have attached 3 different aspect ration wallpapers for you, and we can't let this opportunity go without a shoutout to @CreamGene our talented 2D artist responsible for this artwork.
What about this?

Charge of the Savoia Cavalleria at Izbushensky​


 
Such as might be done in a major update that focusses on supply and logistics, for example? ;)
But it's not something that they can just toss in and get done without either taking more time or removing some other features. The time aspect is dicier then one would think as it's not just a case of delaying the DLC, but only some people can work on this new feature, the rest also needs something to occupie them during that time or alot of money and time is wasted.
 
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But it's not something that they can just toss in and get done without either taking more time or removing some other features. The time aspect is dicier then one would think as it's not just a case of delaying the DLC, but only some people can work on this new feature, the rest also needs something to occupie them during that time or alot of money and time is wasted.
Yes, sure, but I was just saying that, if it were to be done, then a major overhaul of the logistics would be a logical time to do it :)
 
Something I would like to ask about. I have been reading a lot about Germany's Tanks in World War 2 and it seems clear that they had very bad reliability problems (at least after a certain point in the war). From my amateur understanding this was because of extremely rushed development, simplifications to the design to increase production numbers, and because of severe resource shortages requiring the use of inferior parts and inferior materials.

Are these things going to be modeled at all?
 
Something I would like to ask about. I have been reading a lot about Germany's Tanks in World War 2 and it seems clear that they had very bad reliability problems (at least after a certain point in the war). From my amateur understanding this was because of extremely rushed development, simplifications to the design to increase production numbers, and because of severe resource shortages requiring the use of inferior parts and inferior materials.

Are these things going to be modeled at all?
The simplifications to the design to increase production numbers actually improved the reliability and logistical system but everything else is right.

One of the major problems the German's were plagued by in the war were the number of different vehicles they used, captured and not and the fact that many of their own vehicles had slightly different parts.

It crippled their ability to repair and replace vehicles and this isn't actually modelled in game right now beyond "Need to assign more factories to the design"

There's currently no real downside to mass deploying captured equipment or having a hundred different designs beyond factory numbers.
 
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One of the major problems the German's were plagued by in the war were the number of different vehicles they used, captured and not and the fact that many of their own vehicles had slightly different parts.
Maybe we'll get lucky and for the armored vehicles, they will only supply native (ie your country) vehicles. Captured ones have to be converted, making them native (so they can be supplied). Or maybe even turning off allied supply at the depot will also not supply captured (not converted) vehicles.

As far as the parts, the mass production nations (US, Soviets, others?) should get a bonus spirit, that increases their equipment reliability.
 
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As far as the parts, the mass production nations (US, Soviets, others?) should get a bonus spirit, that increases their equipment reliability.
That spirit should also make variants more expensive, since that was the tradeoff.

Maybe make it a replaceable national idea, so that (for example) Germany could go cheap but study, or USA could go all variant-fussy.