Hearts of Iron IV - 38th Development Diary - 18th of December 2015

Hearts of Iron IV - 38th Development Diary - 18th of December 2015

  • Pre order now!

    Paradox Development Studio brings you the sequel to one of the most popular strategy games ever made! Crusader Kings III is soon upon us and you can pre order it today!


    Releasing September 1st 2020

podcat

Oberkommando HOI4
Super Moderator
12 Badges
Jul 23, 2007
12.585
30.039
  • Europa Universalis IV
  • Hearts of Iron III
  • Semper Fi
  • 500k Club
  • Europa Universalis III: Collection
  • Europa Universalis IV: Pre-order
  • Hearts of Iron II: Beta
  • Europa Universalis: Rome Collectors Edition
  • Mount & Blade: Warband
  • Paradox Order
  • Hearts of Iron IV Sign-up
  • Hearts of Iron IV: Together for Victory
Hi everyone, its Friday which means its time for another development diary. This one is all about our underwater friends: The Submarines!

The role of the submarine in Hearts of Iron IV is the same as it was historically: To hunt down enemy shipping and not have to challenge a superior enemy fleet directly to hurt them. Its a particularly attractive choice as Germany who will likely be facing Britain and the massive Royal Navy.

Each nation can research 4 different submarine models, each more powerful and harder to catch.

It is also possible to create variants of these using field experience where you can improve their torpedo attack, stealth or engine speed.

Submarines, like the rest of your ships are affected by doctrines. Here is a screenshot showing the submarine focus branch in the Trade Interdiction doctrine.

It improves the ability of submarines to detect other ships and their organization, but most importantly it improves their coordination while convoy raiding. Whenever a submarine in the fleet detects and enemy convoy this coordination value will control how quickly other submarines can gather and help in the attack (and also get away when cavalry arrives) so it is important for someone focusing on getting the most out of their submarine force.

As mentioned earlier the goal of the submarine is primarily to attack your enemy's economy by preying on convoy routes. For example:
- Attacking convoys along an enemy trade route will deny them foreign resources.
- A nation split across the globe like Britain must convoy home resources to their capital area from many places in its empire to use them, making them vulnerable to submarine raiding.
- When receiving lend lease, convoys carrying equipment can be sunk and will be lost forever.
- When deploying troops on foreign theaters of war a nation must ferry supply and reinforcement equipment to them. By taking out these convoys their troops will be weaker and easier to defeat.
- Troops being transported or during a planned invasion may be attacked leading to them being wiped out or severely weakened. You always want to be very careful and guard your transport routes before sending troops somewhere in war time.

Each convoying route will have a visible efficiency shown in a tooltip indicating on average how much goes through due to attacks and other lack of convoys. Any convoy attacks are shown with indicators on the map that you can check out after battles with a report and will give you a hint on where the enemy is concentrating its raiders. Its advisable to put ships on convoy escort missions to help defend against submarines and other threats.


Most ships are not capable of effective sub hunting, especially not capital ships so having destroyers and light cruisers with a fleet is important for defense and being able to deal with the submarines. Submarines may also be spotted by aircraft so keeping your air superiority in areas will help as well.



In the naval battle above German submarines have managed to sink a large amount of convoys and are about to slip away into the night from the Royal Navy (who have arrived in time to save the last 5). Note that they have an indicator on them that tell you that the enemy does not know their exact location and can't attack them.

This was the last diary before Christmas and we will be returning again after much needed rest with diaries on January 8th!
 

DeclaredYuppie

Major
56 Badges
May 22, 2012
739
940
  • Arsenal of Democracy
  • Cities: Skylines - Snowfall
  • Stellaris - Path to Destruction bundle
  • Europa Universalis IV: Cossacks
  • Cities: Skylines - After Dark
  • Europa Universalis IV: Mare Nostrum
  • Stellaris
  • Cities: Skylines Deluxe Edition
  • Steel Division: Normand 44 - Second Wave
  • Warlock 2: The Exiled
  • Victoria 2: Heart of Darkness
  • Victoria 2: A House Divided
  • Semper Fi
  • Europa Universalis IV: Conquest of Paradise
  • Crusader Kings II
  • Crusader Kings II: Legacy of Rome
  • Crusader Kings II: Sons of Abraham
  • Darkest Hour
  • Europa Universalis IV
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Res Publica
  • Europa Universalis IV: Wealth of Nations
  • For the Motherland
  • Hearts of Iron III
  • Hearts of Iron III: Their Finest Hour
  • King Arthur II
  • Europa Universalis IV: Rights of Man
  • Stellaris: Digital Anniversary Edition
  • Stellaris: Leviathans Story Pack
  • Stellaris: Apocalypse
  • Hearts of Iron IV: Field Marshal
  • Steel Division: Normandy 44
  • Europa Universalis IV: Mandate of Heaven
  • BATTLETECH
  • Hearts of Iron IV: Death or Dishonor
  • Hearts of Iron IV: Expansion Pass
  • Stellaris: Humanoids Species Pack
  • Hearts of Iron IV: Colonel
  • Hearts of Iron IV: Cadet
  • Stellaris Sign-up
  • Steel Division: Normandy 44 -  Back to Hell
  • Stellaris: Galaxy Edition
  • Crusader Kings II: Conclave
  • Europa Universalis IV: Common Sense
  • Pillars of Eternity
  • Crusader Kings II: Way of Life
  • Europa Universalis IV: El Dorado
  • Prison Architect
  • 500k Club
  • Warlock: Master of the Arcane
Very cool, as always :)

How are convoy routes managed? Can the players decide where they want to ship from/to, and either spread out their shipments or condense them to one supply route? I'm thinking of the sense I got in 3 where there were several lines between America and England...
 

madprofmike

Major
29 Badges
May 28, 2006
701
3
  • 500k Club
  • Stellaris: Ancient Relics
  • Stellaris: Megacorp
  • Stellaris: Distant Stars
  • Stellaris: Apocalypse
  • Stellaris: Humanoids Species Pack
  • Stellaris: Synthetic Dawn
  • Stellaris - Path to Destruction bundle
  • Stellaris: Leviathans Story Pack
  • Stellaris: Digital Anniversary Edition
  • Hearts of Iron IV: Cadet
  • Hearts of Iron IV Sign-up
  • Stellaris: Galaxy Edition
  • Stellaris
  • Europa Universalis IV: Pre-order
  • Arsenal of Democracy
  • Victoria 2: A House Divided
  • Victoria 2
  • Semper Fi
  • Iron Cross
  • Hearts of Iron III Collection
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
  • Europa Universalis IV
  • Europa Universalis III: Chronicles
  • Darkest Hour
  • Crusader Kings II
  • Hearts of Iron II: Armageddon
cool
 

podcat

Oberkommando HOI4
Super Moderator
12 Badges
Jul 23, 2007
12.585
30.039
  • Europa Universalis IV
  • Hearts of Iron III
  • Semper Fi
  • 500k Club
  • Europa Universalis III: Collection
  • Europa Universalis IV: Pre-order
  • Hearts of Iron II: Beta
  • Europa Universalis: Rome Collectors Edition
  • Mount & Blade: Warband
  • Paradox Order
  • Hearts of Iron IV Sign-up
  • Hearts of Iron IV: Together for Victory
May i ask if its possible to tell the submarine-fleets to flee automatically, if its facing an enemy (war-)fleet, even if it has the mission to fight convoys?
a fleet on convoy hunting will prefer to hunt convoys rather than fight enemy fleets, but yes you can set your preferred engagement rules so they will avoid scary stuff
 

Denkt

Left the forums permamently
42 Badges
May 28, 2010
15.763
6.202
Each nation can research 4 different submarine models, each more powerful and harder to catch.
Their is no point in building low tech submarines (or other ships) as dockyards lack efficiency?

It is also possible to create variants of these using field experience where you can improve their torpedo attack, stealth or engine speed.
I guess you can also improve reliability, however are not submarines so weak that reability will not matter?
 
  • 1
Reactions: Axe99

Cpack

Field Marshal
33 Badges
Jan 16, 2003
2.980
708
  • Hearts of Iron IV: Expansion Pass
  • Hearts of Iron IV: Cadet
  • Hearts of Iron IV: Colonel
  • Hearts of Iron IV: Field Marshal
  • Cities: Skylines - Natural Disasters
  • Stellaris - Path to Destruction bundle
  • Cities: Skylines - Mass Transit
  • Hearts of Iron IV: Death or Dishonor
  • Cities: Skylines - Green Cities
  • Stellaris Sign-up
  • Stellaris: Apocalypse
  • Cities: Skylines - Parklife Pre-Order
  • Cities: Skylines - Parklife
  • Cities: Skylines Industries
  • Stellaris: Megacorp
  • Cities: Skylines - Campus
  • Hearts of Iron IV: La Resistance
  • Hearts of Iron II: Armageddon
  • Hearts of Iron IV Sign-up
  • Stellaris: Galaxy Edition
  • Stellaris: Galaxy Edition
  • Stellaris
  • Cities: Skylines - Snowfall
  • Cities: Skylines - After Dark
  • Cities: Skylines
  • 500k Club
  • Semper Fi
  • Europa Universalis III Complete
  • Europa Universalis III Complete
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
  • Europa Universalis III Complete
Are there also different stances for convoy attack like "stay closer together and strike as wolfpack more efficiently" or "spread out wide to get a better Chance on detecting, but then have less submarines in range of Engagement"?
 

EntropyAvatar

General
66 Badges
Dec 5, 2008
2.112
2.255
  • Darkest Hour
  • Stellaris - Path to Destruction bundle
  • Stellaris: Galaxy Edition
  • Europa Universalis IV: Pre-order
  • Victoria 2: Heart of Darkness
  • Victoria 2: A House Divided
  • Sword of the Stars II
  • Semper Fi
  • Victoria: Revolutions
  • Europa Universalis IV: Res Publica
  • Leviathan: Warships
  • Heir to the Throne
  • Hearts of Iron III
  • Crusader Kings II
  • Europa Universalis III
  • Europa Universalis III: Chronicles
  • Divine Wind
  • Europa Universalis IV
  • Hearts of Iron III: Their Finest Hour
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Wealth of Nations
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Call to arms event
  • For the Motherland
  • Hearts of Iron IV: Expansion Pass
  • Europa Universalis IV: Mandate of Heaven
  • BATTLETECH
  • Hearts of Iron IV: Death or Dishonor
  • Stellaris: Distant Stars
  • Age of Wonders III
  • Hearts of Iron IV: Expansion Pass
  • Europa Universalis IV: Rights of Man
  • Stellaris: Humanoids Species Pack
  • Stellaris: Apocalypse
  • BATTLETECH - Digital Deluxe Edition
  • Cities: Skylines - Parklife Pre-Order
  • Cities: Skylines - Parklife
  • Hearts of Iron IV: Together for Victory
  • Stellaris: Leviathans Story Pack
  • Stellaris: Digital Anniversary Edition
  • Hearts of Iron IV: Colonel
  • Hearts of Iron IV: Cadet
  • Stellaris: Galaxy Edition
  • Stellaris
  • Europa Universalis IV: Mare Nostrum
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Common Sense
  • Europa Universalis IV: El Dorado
  • Hearts of Iron IV: La Resistance
  • 500k Club
Say a group of submarines in a battle sinks an all the convoys going to some particular destination. Like supplies from UK to North Africa. How long will the supply to North Africa be disrupted from this one event, assuming the UK has lots of spare convoys?
 

Voigt

Lt. General
61 Badges
Mar 15, 2012
1.294
499
Very cool, as always :)

How are convoy routes managed? Can the players decide where they want to ship from/to, and either spread out their shipments or condense them to one supply route? I'm thinking of the sense I got in 3 where there were several lines between America and England...
The last post I know about this was:
You can't set convoy routes yourself, but you can exclude certain areas from the route. So you could in theory just exclude alot of seazones, to let the ships go your preferred way.
But I think this info was from GamesCom 2014, so pretty old.

Maybe @podcat could write if this is still the case or changed.
 
  • 1
Reactions: Axe99

Cpack

Field Marshal
33 Badges
Jan 16, 2003
2.980
708
  • Hearts of Iron IV: Expansion Pass
  • Hearts of Iron IV: Cadet
  • Hearts of Iron IV: Colonel
  • Hearts of Iron IV: Field Marshal
  • Cities: Skylines - Natural Disasters
  • Stellaris - Path to Destruction bundle
  • Cities: Skylines - Mass Transit
  • Hearts of Iron IV: Death or Dishonor
  • Cities: Skylines - Green Cities
  • Stellaris Sign-up
  • Stellaris: Apocalypse
  • Cities: Skylines - Parklife Pre-Order
  • Cities: Skylines - Parklife
  • Cities: Skylines Industries
  • Stellaris: Megacorp
  • Cities: Skylines - Campus
  • Hearts of Iron IV: La Resistance
  • Hearts of Iron II: Armageddon
  • Hearts of Iron IV Sign-up
  • Stellaris: Galaxy Edition
  • Stellaris: Galaxy Edition
  • Stellaris
  • Cities: Skylines - Snowfall
  • Cities: Skylines - After Dark
  • Cities: Skylines
  • 500k Club
  • Semper Fi
  • Europa Universalis III Complete
  • Europa Universalis III Complete
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
  • Europa Universalis III Complete
Is it possible to implement (mod) subhunting planes/ missions where the planes get a Mission in only "subhunting", not also naval attack?
In Hoi3, there were only one type of attack for planes (naval attack)

Separation here would be cool
 
  • 2
Reactions: Ibikyo and adski42

Sharp163

Major
28 Badges
Aug 3, 2015
688
1.746
  • Darkest Hour
  • Europa Universalis IV
  • Europa Universalis IV: Art of War
  • Europa Universalis IV: Conquest of Paradise
  • Europa Universalis IV: Pre-order
  • Crusader Kings II
  • Victoria 2: Heart of Darkness
  • Victoria 2: A House Divided
  • Stellaris: Apocalypse
  • Hearts of Iron IV Sign-up
  • Stellaris: Leviathans Story Pack
  • Stellaris - Path to Destruction bundle
  • Stellaris: Synthetic Dawn
  • Europa Universalis IV: El Dorado
  • Stellaris: Distant Stars
  • Stellaris: Megacorp
  • Imperator: Rome
  • Stellaris: Ancient Relics
  • Stellaris
  • Europa Universalis IV: Cossacks
  • Europa Universalis IV: Common Sense
  • Victoria 2
  • Crusader Kings II: The Old Gods
  • Semper Fi
  • Hearts of Iron III Collection
  • Hearts of Iron III: Their Finest Hour
  • Hearts of Iron III
  • For the Motherland
Hi everyone, its Friday which means its time for another development diary. This one is all about our underwater friends: The Submarines!

The role of the submarine in Hearts of Iron IV is the same as it was historically: To hunt down enemy shipping and not have to challenge a superior enemy fleet directly to hurt them. Its a particularly attractive choice as Germany who will likely be facing Britain and the massive Royal Navy.

Each nation can research 4 different submarine models, each more powerful and harder to catch.

It is also possible to create variants of these using field experience where you can improve their torpedo attack, stealth or engine speed.

Submarines, like the rest of your ships are affected by doctrines. Here is a screenshot showing the submarine focus branch in the Trade Interdiction doctrine.

It improves the ability of submarines to detect other ships and their organization, but most importantly it improves their coordination while convoy raiding. Whenever a submarine in the fleet detects and enemy convoy this coordination value will control how quickly other submarines can gather and help in the attack (and also get away when cavalry arrives) so it is important for someone focusing on getting the most out of their submarine force.

As mentioned earlier the goal of the submarine is primarily to attack your enemy's economy by preying on convoy routes. For example:
- Attacking convoys along an enemy trade route will deny them foreign resources.
- A nation split across the globe like Britain must convoy home resources to their capital area from many places in its empire to use them, making them vulnerable to submarine raiding.
- When receiving lend lease, convoys carrying equipment can be sunk and will be lost forever.
- When deploying troops on foreign theaters of war a nation must ferry supply and reinforcement equipment to them. By taking out these convoys their troops will be weaker and easier to defeat.
- Troops being transported or during a planned invasion may be attacked leading to them being wiped out or severely weakened. You always want to be very careful and guard your transport routes before sending troops somewhere in war time.

Each convoying route will have a visible efficiency shown in a tooltip indicating on average how much goes through due to attacks and other lack of convoys. Any convoy attacks are shown with indicators on the map that you can check out after battles with a report and will give you a hint on where the enemy is concentrating its raiders. Its advisable to put ships on convoy escort missions to help defend against submarines and other threats.


Most ships are not capable of effective sub hunting, especially not capital ships so having destroyers and light cruisers with a fleet is important for defense and being able to deal with the submarines. Submarines may also be spotted by aircraft so keeping your air superiority in areas will help as well.



In the naval battle above German submarines have managed to sink a large amount of convoys and are about to slip away into the night from the Royal Navy (who have arrived in time to save the last 5). Note that they have an indicator on them that tell you that the enemy does not know their exact location and can't attack them.

This was the last diary before Christmas and we will be returning again after much needed rest with diaries on January 8th!
Thanks podcat! This DD was certainly much awaited :D

Quick question: will we still have to assign subs/naval units to regions, or can we just tell them which supply line to attack (or to disrupt trade between two particular nations)?
 
  • 1
Reactions: Mouts