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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.

Untitled.png


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.

uboateffort.png


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.

Sub Minelayer.png


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.

WolfPacks.png


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.

casualties.png


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.

Canada War Support.png


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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Raiding and Reaving 1940 edition

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.

View attachment 428570

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.

View attachment 428585

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.

View attachment 428580

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.

View attachment 428583

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.

View attachment 428584

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.

View attachment 428586

By early ‘41 England 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 Russia.

See you all next week!

Rejected Titles:
-Raiding and Reaving, 1940 edition
-Subs, theyre not complete trash now!
-Under the sea, Darling its better
Two diaries in one week, you're spoiling me paradox. Really loving how the game is progressing so far.
 
Hello again,

in 1 of my former posts i already wrote about "auxiliary cruiser" but its maybe forgotten .

Handelsstörkreuzer (HSK) in fact the english wiki about german auxiliary cruiser does not exist but there were 10 of it . https://de.wikipedia.org/wiki/Deutsche_Handelsstörer_während_der_Weltkriege#Deutsche_Hilfskreuzer_im_Zweiten_Weltkrieg

no english wiki avaiable, use google translate

The total of ten equipped auxiliary cruisers were able to sink 133 ships with a total tonnage of 829,644 tons in the 43 months of their operation - almost twice as much as the tonnage sunk by conventional German warships.

They were also used for mine laying and nearly invincible cause they had merchant camouflage heres the story about Raider F (Pinguin) https://en.wikipedia.org/wiki/German_auxiliary_cruiser_Pinguin

Please just tell : Do you plan to add "auxiliary cruiser" to the HOI MTG DLC?

I wish so...............

(Those interested in movies may like the italy movie https://www.imdb.com/title/tt0054328/ about a german auxiliary cruiser made 1960 ) heres the trailer first 5min.
 
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Well as long as submarines don't try to go head on against enemy destroyers as their first target and get utterly destroyed in the process. They should be sneaking around to try and "backstab" battleships and aircraft carriers, otherwise they'll remain useless in fleet vs fleet battles
 
Please since an apparent bug with subs, they couldn't give naval superiority for manual invasion like couldn't do support to invasion.

I saw 2 times different cases when subs from green cape or Portugal give naval supremacy to get a invasion from argelia to barcelo na thought Gibraltar in enemy hands I agree they shield pad but can't work that way
 
nice additions. Used to hunt convoys with a surface fleet and while fun and effective it was a shame we could not use subs to its full potential.

Hope to heavily penalize players that ignore navy now :).
 
Ship designer question -- what dictates ship range, and can I make tradeoffs that increase ship range without spending too much more production? Primarily, the idea for ASW destroyer squadrons escorting out in the Mid-Atlantic Gap is that they don't need to be fast or strong, but they do need a lot of range to actually patrol out that far. Is my only option for improving destroyer range to accept the IC cost of later-model hulls?
 
One way to deal with some of these issues would be to implement the Civilian Factories mechanic for Convoys as well. The more civilian laws would use up a large percentage (30%? 50%?) of Convoys for Civilian Convoys. More militarized laws would reduce this, freeing up Convoys for strategic Resources, naval invasions, etc. The AI algorithm for spending PP would need to be adjusted somewhat, but IMHO it needs urgent attention anywhere as I keep seeing nations large and small that are hamstrung by spending their PP on generals and designers rather than laws.
This is a good idea, if they would have to be on the oceans, and prone to be sunk.
 
and plane catapults. These plane catapults boost the sub’s surface detection, giving them an advantage in being detected and helping them remain invisible
If sea planes/flying boats can be launched from the plane catapults, not just a increase in surface detection value, then it would make the convoy raiding and escort more vital and realistic as it is in history!
 
Hopefully AI will be capable to defend at least somewhat, as what I see here suggest it is not at all capable to defend itself.
1 sub lost vs 20 DDs, carrier and literally hundreds of convoys? UK AI even lost 8 subs of it own - That do not look like there was fight at all, just unopposed slaughter.

Besides, subs with planes in Atlantic is completely wrong, and in English Chanel, completely improbable.

Japan used them, but that's because Japanese subs were not supposed to hunt for merchant traffic - they were scouts for battle fleet.
On the other hand, subs in Atlantic would not have the comfort of using planes simply because it took a lot of time on surface to assemble and launch the plane. And while an hour may be acceptable in vastness of the Pacific, same hour in daylight on English Channel means a sub lost, essentially.
Not to mention, that a plane hangar is very bad for manoeuvring - making diving much slower (resulting in a much higher chance of successful air attack), turning underwater much harder, and increasing drag, resulting in a lower speed and shorter battery life.
Plus, in the weather in northern Atlantic, the hangar would interfere even with sailing on surface.

Essentially, a hangar is a last thing you would like to put on a raiding submarine.
 
If i play as germany and choose "Return of the Kaiser" iam 150% sure the Felix Graf von Luckner (9 June 1881 – 13 April 1966) would immediatly return as high rank officer to the german navy. https://en.wikipedia.org/wiki/Felix_von_Luckner

Same like Paul Emil von Lettow-Vorbeck (if returning Kaiser ) but for german navy

While Dönitz (who was a true Nazi) should NOT be avaiable if returning back the Kaiser.

Fix that as soon as possible

Thanks
 
All of those points sound more like "The German surface raiders made a good fleet in being that required the British care about them" than "The German surface raiders were a wise investment for raiding convoys to defeat a superior naval power in a struggle on the ocean."

Building a balanced surface fleet was not a wise investment for WW2 Germany. I do agree with you in the fact that submarines are far more efficient in raiding missions against a superior naval power than surface vessels since they have an easier time escaping and are cheaper to replace if sunk.

Now, that is not to say that the surface elements of the Kriegsmarine had no value as a raiding force. As I told you as an example the Scharnhorst and Gneisenau had a successful raid in the Atlantic as they sank more than 20 vessels while escaping from the Royal Navy.

If Germany and Britain had a more close ratio on ships as in WW1 I fully believe that surface raiding in the Atlantic would have been quite feasible for the Germans and actions like that would have been common. Japan for example has Operation C as an example of a successful surface raid against an "equal" opponent.
 
Or as the leader of the free world put it back in April 2017: “We are sending an armada. Very powerful. We have submarines. Very powerful, far more powerful than the aircraft carrier, that I can tell you”
 
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.

Hi Bobby, how this tech system fit with the numerous pre-war large cruiser submarine?
These kind of submarines were largely present already before 1936 (often from the WWI), now they seem only searchable after the start of the game with a special tech.

Examples; Surcouf, Narwhal-Class, Type U-139 and Type U-151, Type J1, Type B1, Type AM, XMS X1, Kaidai-Class, K-Class, Type IXD2, Cagni-Class, R-Class, Fieramosca-Class, Foca-Class.
 
Even with this changes, not sure I will every invest my research not just into new Submarine Models and Modules, but also a complete Doctrine Path (Naval). Especially in a MP I not sure if a competent UK and later USA will let their convoys get sunk so easily.

While I read this dev diary, I thought: Why do we even have to research doctrines? Shouldn't it be better, if we just chose a path, and alle three doctrine trees gets progessed automatically, without using one to three reseach slots?

Let different Foci boost the speed the progession for a while, and let it progress much faster when fighting in the correct category, similar like we can invest Army EXP in MtG for faster Landdoctrines.

Well I mean, that’s kinda the point, no?

Irl Germany couldn’t bring herself to prioritize this aspect of warfare, so should be the case for the player, unless their strategy differs from historical germany.

At least today, with these changes a submarine strat become viable. Previously it was never a choice never a decision.

I like that no country can do everything, that choice are made and sacrifices realized.