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HOI4 Dev Diary - Amphibious Vehicles and Research

Hi everyone! Another wednesday means its diary time! Today we will be talking about some quite big balance changes to tech as well as some new... watery toys :)

Amphibious Armored Vehicles

With Man the Guns we are adding two new classes of vehicles. Amphibious Tractors (AMTRACs) and Amphibious Tanks. AMTRACs were built in large quantities and used both in the Pacific by US Marines with good success as well as in Europe during major river crossings such as the Allied crossing of the Rhine. An AMTRAC is a amphibious tracked vehicle that offers soldiers protection, and depending on model, firepower when conducting landings.

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For heavier armor and firepower, amphibious tanks were developed. The allies used quite a lot of the Duplex Drive Shermans during D-Day. The idea was that the tanks would swim to the beach, then drive on to assault the German fortifications. The Sherman DD itself had some design problems, as it was designed for only 30cm high waves… which aren't exactly rare at sea. Many of them were also unloaded from their landing ships much too far out and sunk in the waves. Some beaches had good results, but for example Omaha beach was a disaster where most of them were lost. The Germans also planned for tanks for Operation Sealion, but experimented with snorkels and driving along the bottom instead. These were instead used during Barbarossa. The Japanese went more in the direction of attachable “flotation parts” with the Ka-Mi and Ka-chi tanks, making them look like tiny little warships. They never got the same large scale testings as the American tanks, but to me at least, seem to have been a more reasonable technical solution.

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These things combined means that you can design divisions to punch through heavily defended landing sites. Quite useful late game! These divisions are also great for when the enemy has fortified across a large river. On the flip side they are quite expensive to make, less fuel efficient and a little slower for what you get so you should have some plan for them before investing. Amphibious vehicle battalions also use your special forces limit, just like marines.

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Man the Guns comes with 10 unique 3d models for the amphibious tanks:
mtg_amphibious_eng_sov.png

mtg_amphibious_ger.png

mtg_amphibious_usa_generic.png

mtg_amphibious_jap.png


The mechanized infantry AMTRACs can be found in the Infantry tech tab while the Amphibious tanks are a branch of light tanks (the tier 2 amphibious tanks are close in stats to the 1939 medium tanks):

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Research Changes
We are changing up some things when it comes to technologies as well. Because we have been steadily adding more, and are adding a bunch more with Man the Guns, we will be adjusting the base research speed to be faster. Probably something like +10%, but we haven’t locked that down yet.

We are also changing how the formula works for calculating how long it takes to research things. Instead of a research bonus lowering the cost of the research, bonuses now affect the speed of research. This means that an old -50% cost modifier is roughly the same as a +100% speed modifier now. I say roughly because speed modifiers stack a lot better and in less odd ways when there are many of them. This essentially means that you can no longer get instant techs by stacking various modifiers, just really fast research.

We have also changed how ahead of time works and the Ahead of Time Bonuses from focuses etc. no longer give you a percentage off, but a number of years off. This is important because it makes certain tech rush strategies where you simply bypass much of the tree by chaining ahead of time bonuses not work. We feel that these things will make things play a lot saner, and stop ahead of time researching to be banned in some MP groups ;)
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The other change we are doing is to allow certain techs to get a bonus from XP. All doctrines as well as certain modules like torpedoes get a research boost when spending XP on them. This does two things for us: On the one hand we are not happy that one of your research slots is basically always locked to land doctrine research, and also the fact that we don’t really want nations to have maxed out their doctrines by the start of the war. So doctrines now get a bit slower to research, but by spending XP (benefitting the nations we want to have an edge here, like the axis) you will be researching faster than before. The other thing is to model certain stuff that were notoriously hard to get working right, like torpedoes, which for some periods of time had something like a majority failing to actually detonate when hitting a target. We want nations who get to see action here or dedicate training time on it to have a bit more of an edge.
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That’s it for this time! Do not miss that we are starting streaming of Man the Guns gameplay today, so tune in to see the new USA tree at 16:00 CET at https://www.twitch.tv/paradoxinteractive
 
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Wonderful job all round, a great addition. Something I'd been hoping for this patch. Should make the pacific war a little more varied and interesting. Also finally a reason to build armour as Japan.
 
Nice ideas here, although unsurprisingly I can't quite grasp how the new research balancing will play out. Time will tell. Please be careful how you apply XP to research bonuses, because experience mining is quite easy in this game. That would produce instant breakthroughs via another route.

And it would be nice if the reliability rating of those amphibious tanks were set at an appropriately low level!
 
@podcat

This stream just indicated exactly why you should add a 1-2 second non-click timer on event options!
 
Will it be possible to convert outdated light/medium tanks to amphibious tanks? If the Schwimmpanzer historically was a converted Panzer II, it would make sense to have it be convertible in game.

Also, really boring title for the Dev Diary. Didn't you have any alternative suggestions?
 
Will it be possible to convert outdated light/medium tanks to amphibious tanks? If the Schwimmpanzer historically was a converted Panzer II, it would make sense to have it be convertible in game.

Also, really boring title for the Dev Diary. Didn't you have any alternative suggestions?
Or maybe, a 4th variant for a tank. Possibly worse than base model overall and worse at seaworthiness than specific-built equipment, but cheaper to research and produce.
 
I think it's more likely refining techs, since it branches off from synth tech.
Yeah, you're right. I kinda forgot it's building fuel tanks that increases the stockpile ceiling.

Also, Mexico had a civil war in the stream so looks like the other minor getting a focus tree is indeed Mexico.

EDIT: Ninja'd.
 
Will the factions of past DLCs (Hungary, Romania, Yugoslavia and Czechoslovakia for DoD, etc.) get unique 2D art for their ambhibious tanks as well?

I'm not aware that any of them had an amphibious tank project. Two of them are landlocked nations that don't even have a navy!
 
I'm not aware that any of them had an amphibious tank project. Two of them are landlocked nations that don't even have a navy!
B-b-but muh Danube gunboat navy! Grand Admiral Horthy demands floating Turáns!

Also Air is Our Sea! Flying tanks for Czechoslovakia!!!
 
Here is the full list of vehicles (3d models are as you can see in the picture in the diary):
LVT-1(A)
Sherman DD
LVT-2
LVT-4
Type 2 Ka-Mi
Type 3 Ka-Chi
Type 4 Ka-Tsu
Schwimmpanzer II
Tauchpanzer III
Land-Wasser-Schlepper
Land-Wasser-Schlepper II
T-40
PT-76
Valentine DD
Cromwell DD
Terrapin

No DUKW? Bostonians will be horrified.
 
@podcat The dev diary is not showing on steam again and also great work this stuff it looks amazing!