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HoI4 Dev Diary - Subs and Convoy Raiding

Greetings, I am a game designer new to the HoI4 team. This is my first dev diary, so be gentle ;). Also, sorry for the late post today. I am an American and when it comes to WW2, we show up late.

Today’s diary entry covers our improvements to submarine convoy raiding. In past versions of HoI4, submarines have not really pulled their weight. We have sought to change that and make them worthwhile to build. I recently put these changes to the test by playing a Germany campaign.

My naval plan as Germany was to exploit the central Atlantic and Cap Verde Plain with a submarine wall. This would hopefully prevent England from getting necessary resources from the USA and the colonies. The biggest effect of this resource shortage would be the UK running out of fuel, crippling both their navy and air force. This would hopefully open the UK to sea lioning before the USA joins the war or at the very least, make winning the air war very easy and cause permanent damage to the UK’s fleet.

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We have previously mentioned the spotting system, and how naval task forces are revealed over time. This functions a little bit differently for subs. Spotting an enemy sub outside of combat is based upon chance. The chance for this to happen is based on how quickly the spotter will spot their target. However, it is possible for a submarine to have a large enough advantage in spotting that the submarine task force will not be able to be spotted. However, convoy escorts will still be able to fight against submarines once combat is initiated, even if subs are not normally detectable by enemy taskforces on the map.

This system creates a tech race between sub stealth and sub spotting, with subs having a better chance of getting an advantage in the early game. Previously, submarines would eventually be detected and killed no matter how good at hiding they were. This is no longer an inevitability.

Before beginning the war, I made sure to complete the German naval focus line down to “U-boat Effort.” Along with getting a research speed boost and some dockyards, the focus gives Germany access to a “Cruiser Submarine.” This sub is a sort of tech 2.5 Sub with extended range, some unique module options, including catapult planes, and the ability to be upgraded with a snorkel.

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Part of my plan for giving England a hard time included mining up the English Channel. I executed this plan with a cruiser sub equipped with naval mines and plane catapults. These plane catapults boost the sub’s surface detection, giving them an advantage in being detected and helping them remain invisible, at least for the first couple years of the war.

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I made a tech 3 sub-variant for minelaying the Eastern North Sea and a tech 3 raider-sub for Cap Verde Plain. When I demanded Danzig from Poland in August of ‘39 I had 79 Subs of various roles ready and much of the Trade Interdiction doctrine complete. This focus on raiding will give my subs a further detection advantage over other countries that have yet to complete their convoy escort doctrines.

Speaking of the naval doctrines, we have made some changes all around to account for the new combat system and apply a bit of balance. In particular, we have given some buffs to the Trade Interdiction doctrine to make it more attractive than it was previously. We have added additional survivability for submarines and more of an edge in surface detection values. Capital ships have received some defensive increases as well.

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Torpedo reveal chance is a new thing for subs. When subs are in combat, attacking no longer guarantees that a sub will reveal itself. Baseline, subs have a 50% chance to reveal themselves when launching a torpedo volley. This can further be improved through doctrines and admiral traits. This makes ambushing protected convoys safer and retreating when too many destroyers show up easier.

In my campaign, I capitulated France in early December of ‘39. To help with the Axis’s naval situation I formed Vichy France. Before France fell they had been contesting my raiding of Cap Verde Plain to the best of their ability, but I was still seeing some success. Forming Vichy France put more ships in the hands of the Axis and would further help to stretch the limits of what England could endure at sea.

With Vichy France on my side, early 1940 saw a massive spike in convoys raided as Cap Verde Plain and the Mid-Atlantic were now completely covered. By this point, I had ~20 dockyards producing subs for minelaying and raiding. All of my newest tech 3 Raiders were seeing great success in under the guidance of Karl Dönitz. Even when contested by British convoy escorts, they were able to get a respectable amount of kills and retreat. Naval bombers were also ramping up operations in the English channel.

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We have added a new effect to convoy raiding, war support reduction due to raiding. By mid-1940, Canada had been raided to 0 convoys and had their war support reduced to a point where they were no longer able to support War Economy. This helps to promote raiding and discourages blunt forcing convoys through an area where you are being raided.

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By early ‘41 the UK had been choked out of convoys and fuel and was unable to keep their navy running and were about open to a naval invasion. By mid ‘41 I had naval invaded the UK and was Setup for an attack on The USSR.

See you all next week!

Rejected Titles:
-Raiding and Reaving, 1940 edition
-Subs, they're not complete trash now!
-Under the sea, Darling its better
 
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There was this oil field discovered in England in 1940 or '41 or some such year and helped fuel British home operations during the convoy raidings and effectively saved Britain from invasion. Will this ever be implemented into HOI4?
 
There was this oil field discovered in England in 1940 or '41 or some such year and helped fuel British home operations during the convoy raidings and effectively saved Britain from invasion. Will this ever be implemented into HOI4?

The total amount of crude petroleum produced in all of UK during their peak in 1943 was 839 thousand barrels, compared to the global total of 2'231 million barrels. This means that in HoI4 UK could hope to extract roughly 1 unit of Oil in 1943 if historical decisions to prospect was added. I am pretty sure that such a small amount neither saved UK historically, nor would add enough to be meaningful to have in HoI4.

Source

What saved UK historically was all the tankers that kept on delivering fuel from USA and elsewhere despite the German submarines attempts to sink them.
 
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What petroleum the British had came from their companies in Iran and Burma. They also had a 23% share of the profits of the petroleum production in Iraq.

In the stream we saw that the Dutch begins with oil in the Antilles to represent Venezuelan oil refined by the Royal Dutch Shell Company. And in dev diaries we saw that Mexico's petroleum production is owned in part by USA.

The Devs should do something similar with British explotation in Iran as the gulf was quite important to supply the Royal Navy and the British should not pay civilian factories to get petroleum they owned in that time@podcat
 
What petroleum the British had came from their companies in Iran and Burma. They also had a 23% share of the profits of the petroleum production in Iraq.

In the stream we saw that the Dutch begins with oil in the Antilles to represent Venezuelan oil refined by the Royal Dutch Shell Company. And in dev diaries we saw that Mexico's petroleum production is owned in part by USA.

The Devs should do something similar with British explotation in Iran as the gulf was quite important to supply the Royal Navy and the British should not pay civilian factories to get petroleum they owned in that time@podcat

There was also some either refining or production in Trinidad or that neck of the woods (which iirc is already represented on the map), and British firms had concessions in Venezuela as well (and in a few other spots in the Middle East) - but there's no question that Iran was the biggest single source for them.

As @Alex_brunius well says, the domestic oilfield they found during the war wasn't really strategically significant. They did have some useful refining capability, but from Oil, a Study of Wartime Policy and Administration (relating to UK petroleum product management at the strategic level during WW2 - available on kindle at a pretty reasonable price for anyone that wants a fairly dry read :) ), crude petroleum output in the UK totalled 405,000 tons between 1939-1945, which would have lasted a dash under two weeks based on UK consumption alone (so doesn't count Middle East or Far East consumption) - the average weekly consumption of petroleum products over the period June 1940 to May 1941 was 230,500 tons. It might be a nice flavour thing, but there just wasn't that much oil in the deposit that had been found (at Eakring, in Derbyshire).
 
Historically the Japanese Imperial Navy had subs that had planes that could strike, in fact that was the plan when the Japanese sent a mission to bomb the Panama Canal with submarine Catapult planes (but had to back off because I believe the war ended). It would be nice if there was a small tech tree added for that.

I and some other community members would like to see this submarine in the game. I am more interested in the operational range of the submarine I400 class that was very big (enough to go to operate in almost any part of the world departing from Tokyo). If they implement the submarine one event of this attack could be made.

I hope paradox listen to us.

Could the community member who read this give your opinions about this, please? It would help us to know how many people would like to see this sub in the game.
 
There was also some either refining or production in Trinidad or that neck of the woods (which iirc is already represented on the map), and British firms had concessions in Venezuela as well (and in a few other spots in the Middle East) - but there's no question that Iran was the biggest single source for them.

Yes of course, by 1936 at least 90% of Venezuelan Oil was refined and exported from Curacao, Trinidad or directly in USA.

The thing here is that while Venezuela had a production that in the 30's outclassed Mexican or Iranian oil production the lions share of Venezuelan Oil went to American and Dutch companies.
 
This is all very nice but can we please get better tech and production sprites. Every aircraft carrier at every tech level for every country looking the same makes the game seem half finished. As a guy who makes a lot of custom graphics I know how comparatively little effort this would be. Get on it Paradox.
 
I honestly don't care about sprites.
 
The thing here is that while Venezuela had a production that in the 30's outclassed Mexican or Iranian oil production the lions share of Venezuelan Oil went to American and Dutch companies.

In terms of Dutch companies, it's worth keeping in mind that Royal Dutch Shell was a joint Anglo-Dutch company and, more importantly, many of it's international investments were in-effect available to the British as 'preference buyers'.

This was the last attempt to bring all the properties of the Royal Dutch/Shell Group under British financial control. It is doubtful, however, whether Britain lost very much, for in all its operations outside Dutch territories the Group continued to behave as a British company, working through British-registered companies controlled through the Anglo-Saxon Petroleum Company in London. The company’s expansion between the wars brought valuable holdings in Venezuela under British managerial control. By the eve of the Second World War these Venezuelan fields, which were regarded as reliable war-time sources, were producing about 11 -4 million tons of oil a year." (from "Oil. A Study of War-time Policy and Administration" by D J Payton - Smith, loc 496)

In this context, it's worth noting that between Mar 1940 and May 1940 the Caribbean accounted for 47.7 per cent of oil imported into the UK (with the US 17.0 per cent, Iran at 16.8 per cent and the Eastern Med (Iraq, more or less - there was a pipeline to Haifa) 11.0 per cent. Between Dec 1940 and May 1941, the share of the Caribbean had risen to 63.4 per cent. Once US imports got going it dropped to 41.6 per cent between Jun '41 and Nov '41 (although the net amount still rose a little), before both the share and the net amount dropped substantially later in the war.

All info from Oil: A Study of War-time Policy and Administration. Sorry to be boring!
 
It is not boring at all, in fact is quite interesting to learn how the great oil conglomerates worked. I hope someday we can see in the game how tight was the allied control over worldwide oil production.

In the game you can ask Iran, Venezuela or Iraq for petroleum if playing as Germany as long as you can protect the convoys. In real life that was not possible because even if their regimes were fond of Germany the oil production was in control of American, British and Dutch companies.
 
I and some other community members would like to see this submarine in the game. I am more interested in the operational range of the submarine I400 class that was very big (enough to go to operate in almost any part of the world departing from Tokyo). If they implement the submarine one event of this attack could be made.

I hope paradox listen to us.

Could the community member who read this give your opinions about this, please? It would help us to know how many people would like to see this sub in the game.
As long as it doesn't turn up until around mid 1945, it should be tied to the last sub tech, and require significant resources to produce. In reality it turned up too late to make any impact at all, only 3 were made before the end of the war and all 3 were sunk. As the player, if you wanted to rush research on a tech like this and see it operational much before Mid 45, you would have to ignore research in other areas, and even then, it should still take a fair chunk of time.
 
They're not sprites, either. They're 3D models.
Nope. I'm talking about the 2d imagines in the tech tree and production tab. I couldn't care less about the 3D models on the map. I prefer counters anyway. 5km tall german infantry striding across Poland looks pretty fucking stupid, but I guess Paradox has to appeal to the casuals or they wouldn't make any money.
 
As long as it doesn't turn up until around mid 1945, it should be tied to the last sub tech, and require significant resources to produce. In reality it turned up too late to make any impact at all, only 3 were made before the end of the war and all 3 were sunk. As the player, if you wanted to rush research on a tech like this and see it operational much before Mid 45, you would have to ignore research in other areas, and even then, it should still take a fair chunk of time.
U-boats with water-tight hangars to carry planes were produced in Japan as early as 1929 (J1M, I5, Junsen). Armed planes are available, at the very least, since 1941 (Yokosuka E14Y).
 
Nope. I'm talking about the 2d imagines in the tech tree and production tab. I couldn't care less about the 3D models on the map. I prefer counters anyway. 5km tall german infantry striding across Poland looks pretty fucking stupid, but I guess Paradox has to appeal to the casuals or they wouldn't make any money.

It's not that ridiculous, as a battle planner on a world map they had models depicting army groups, battalions etc. in real life, think about it. This is a grand strategy game not a C&C.
And saying Paradox wouldn't make money if they didn't appeal to casuals is arrogant and complete conjecture..
 
And saying Paradox wouldn't make money if they didn't appeal to casuals is arrogant and complete conjecture..
You're probably right. Everyone knows that the hardcore wargame HOI3 did every bit as well commercially as dumbed-down Hoi 4. I'm not saying one is better than they other either. I am just saying Paradox made a conscious decision to simplify a lot of the mechanics, make the interface less dreary, and generally expand their player base beyond hardcore gamers.