Hearts of Iron IV - 48th Development Diary - 11th of March 2016

[podcat]

Hi everybody, the topic for today is Naval Invasions.

The main design goal for naval invasions has been to make invasions something that requires a lot of preparation to make it possible to pull off, combat "gamey" tactics of sneaking troops in when others are not looking and make it clear how you go about defending yourself, something that requires both navy, air and land.

Let's start with what is required to do a naval invasion:

• You need to position troops at a starting naval base and draw up an invasion plan for where you want them to go.
• Before the invasion can be launched you need to prepare the invasion. This is first a matter of needing a certain amount of convoys available (which the invasion plan will grab) and a time. Both these depends on just how big this invasion is. Small invasions can be planned and executed quickly but large amount of divisions will require plenty of preparation time.
• For each strategic area you pass through with the invasion plan you must have sufficient Naval Supremacy. You get that by having sufficient amount of ships on patrol and by controlling the skies (air superiority). If you do not control these things you won't be able to invade (no sending your whole army to suicide). This makes it pretty clear now to defend as well. For example as UK - as long as your fleet is strong and stationed around the island and your air force is up and about you can feel safe from naval invasions.

There are also things you can do to improve your chances of successful invasions:

• Use special troops - Marines are much better than other troops for securing the beach.
• Make sure to always have ships set up as escorts. Even if you have sufficient naval supremacy to launch the invasion - if the enemy rallies their whole fleet after the invasion is already under way there is still a chance some of the convoys could get intercepted.
• Station battleships in the destination coastline. They will support the invasion with naval bombardment which will help your guys get the edge when fighting on the beaches.
• Use a commander with the Invader trait, he will help speed up the preparation as well as speed up to time it takes to get invading troops ready for fighting.
• And finally: make sure to research transportation technologies. The really useful ones are only available from 1940 (unless you research ahead with the penalties for that), but you can improve things like: Needing less transports to carry out invasions, halving the preparation time required, get extra defense from damage taken during invasion and speed up the time it takes for your troops to get out of the ships and on to the beach where they can fight.

The actual invasion combat has some special rules. Once troops land they first need to unload from ships and during this time they are unable to fire back effectively. If you have the right technologies researched troops will actually get some extra protection during this time, but still it's something you want to do as quickly as you can. Once on the beach they can fire back, but will still be suffering from naval invasion penalties.

Next week we'll talk about nukes!

 

[sermaciej]

Great diary, can't wait for the nukes!

 

[Price21]

YAS

 

[vector1]

I'm actually very interested in how much supply is secured when landing on a beach/harbor. A rough guide would be nice since a lot of forces were lost in WWW to supply issues after landing!

 

[BaReLy.]

Will convoys be locked for invasion plans or can you just not execute the order if you're lacking convoys?

 

[Boozdeuvash]

Sounds more structured than in previous games, and that's nice.

How does one integrate airborne troops into the whole thing?

 

[CheesySnake]

As well as marines can we land amphibious tanks and the like? Or only infantry?

 

[EleventhAvenue]

The actual invasion combat has some special rules. Once troops land they first need to unload from ships and during this time they are unable to fire back effectively.

Just a random thought: Would this mean that it might be worthwhile to make ''Coastal Artillery'' units, consisting of large amounts of artillery and maybe a battalion of infantry, with really high Soft attack but practically no defensiveness/organization? Just to take use of the phase where the attackers can't fire back. Weak countries with a lot of coastline, such as Sweden, are probably not going to be able to effectively defend every part of their coastline with proper divisions, but giving the enemy forces a good wallop while they're landing might weaken them and make it easier for regular army divisions to defeat them when they arrive. I imagine, that even with a port captured, an invading army will most likely be in a much worse situation supply-wise than the country being invaded.

 

[ruzen]

tactical nukes ... next week.

 

[PlacidDragon]

yay, thanx podcat

*takes notes for Japanese playthrough*

 

[Daffius]

combat "gamey" tactics of sneaking troops in when others are not looking a...

• You need to position troops at a starting naval base and draw up an invasion plan for where you want them to go
  
• Before the invasion can be launched you need to prepare the invasion. This is first a matter of needing a certain amount of convoys available (which the invasion plan will grab) and a time. Both these depends on just how big this invasion is. Small invasions can be planned and executed quickly but large amount of divisions will require plenty of preparation time.
• For each strategic area you pass through with the invasion plan you must have sufficient Naval Supremacy. You get that by having sufficient amount of ships on patrol and by controlling the skies (air superiority). If you do not control these things you won't be able to invade (no sending your whole army to suicide). This makes it pretty clear now to defend as well. For example as UK - as long as your fleet is strong and stationed around the island and your air force is up and about you can feel safe from naval invasions.

Will the enemy get notification of the plans? If not, how exactly is it different to what is in HoI3 from say Germanys perspective. They will not have naval superiority in most of the cases and the attack will be just as suprising to them as it is now. Or am I missing something?

Will withdrawal also need a plan?

 

[RolandRahn]

Thanks for the info!

I hope that this means that sealion is no longer an option for the German player?

In HOI3, sealion was so easy that as a German player against AI, it was gamey to do it.

 

[BeauNiddle]

Can naval invasions be part of a multi stage plan - i.e. land here then advance to this battle line?

Will they get the full planning bonuses whilst sitting in port?

Or is it the invasion is just the landing and you need to plan the break out separately (once you are already at your destination)

(I'm fairly certain it can be multistage but we only saw invasions with no breakout in the WWW streams)

 

[paranoidsteve]

Is there any range limitation to invasions? Or could I invade from New York landing in Singapore?

When doing a long range invasion can I move the route taken (like I can the axis of advance in an army plan), so as to avoid areas I don't want to pass through? i.e. in this invasion could I go around the cape of good hope rather then through the med. and suez?

 

[tedski]

I'm assuming I can delegate a lot to the AI like HOI3? In fact apart from diplomacy and telling the theatres what to do it was all AI.

The AI for theatres was good but not really good at naval invasions.

I play HOI3 like this a lot and still get excellent enjoyment out of it.

 

[Porkman]

Will submarines affect naval supremacy?

Historically, the Japanese lost a lot of ground troops to us submarines as they were in transit, even in 1942-43 where the Japanese still had naval supremacy in the West Pacific.

 

[SpermCube]

Can only battleships be used to support naval invasions?

 

[Subbak]

Do coasts get special terrain modifiers for naval invasions? For example doing a naval invasion in the point of Brittany would probably be lead to a longer time before troops are in fighting shape (rocky coast, harder to run across). The presence of a cliffside next to the beach would also presumably be a big problem.

 

[Porkman]

Also, how are sealifts between friendly territories handled?

I'm worried that someone could plan a lightning 1 division invasion with minimal prep and then land 10 divisions behind. Not unlike the old hoi2 exploit of taking plymohth with paras and then having transports preloaded with the entire 6th army sneak in.

 

[Daddl]

Will the enemy get notification of the plans? If not, how exactly is it different to what is in HoI3 from say Germanys perspective. They will not have naval superiority in most of the cases and the attack will be just as suprising to them as it is now. Or am I missing something?

Will withdrawal also need a plan?

It was said some time ago that you could get a notification about an invasion while your enemy is still preparing it if you have enough intel, giving you time to react. Don't know if thats still a thing though. Other than that, if Radar works the same as in HoI3, you might notice a few dozen divisions standing in a port for some weeks.

There were quite a few withdrawals in the WWW, and they were so fast, I don't think a plan was needed for that.