• We have updated our Community Code of Conduct. Please read through the new rules for the forum that are an integral part of Paradox Interactive’s User Agreement.

Hoi4 Dev Diary - Naval Treaties and Ship Refits

Hello, and welcome back to another exciting dev diary about ship design!

As many of you noted last week, ship design in the interwar years was heavily restricted by the Washington Naval Treaty and the First London Naval Treaty. During and after the Great War, naval planners the world over were drawing up plans for new battleships that made use of new technologies, with ever bigger guns requiring ever stronger armor meaning increasingly large ships that were becoming even more expensive. At the same time, Britain and France were at the edge of bankruptcy from the debts they had accumulated during the Great War and could not afford another naval arms race with the fairly untouched nations of Japan and the US.

The result was the Washington Naval Treaty of 1922, which forbade any new battleship construction for a period of 10 years and restricted the maximum size of ships as well as their gun armament. In 1930, the signatories of the Washington Naval Treaty came together and negotiated the London Naval Treaty, which limited the construction of cruisers and stipulated strict restrictions on their size. In early 1936, the London Naval Treaty was up for renegotiation and that, as they say, was when the trouble started.

These restrictions forced the designers of warships in the interwar period to come up with some interesting compromises, and although we can’t possibly model all the interconnected ways in which these restrictions impact design - the Nelson class baffled American designers who were trying to comprehend why the British would build a ship like that - we did want to model some of the impact and also represent the diplomatic effects of the naval treaties.

picture_naval_treaty.jpg


All the signatories of the 1930 London Naval Treaty will start with a national spirit that restricts the maximum cost of their capital ships. As I said last week, we originally played around a bit with tonnage as a restricting value for ship design, and obviously this would have tied in neatly with the Naval treaties, but the design was changed later to instead focus on slots and construction cost. We also thought about simulating the restrictions in gun caliber etc. through restricting modules, but in the end decided against it because it would disincentivize the player to engage with the ship designer - imagine researching a new heavy battery and then finding out that you can’t install it because it would violate the treaty! It still means that in ship design, you can’t just build the best possible ship on day one as the cost restrictions are quite harsh.

treaty_bs.jpg


When you start the game in 1936, you will notice a mission ticking down reminding you that the Second London Naval Conference is currently underway. If you don’t decide to bail, you will automatically sign the Second London Naval Treaty. Bailing from the treaty is at first only available during the London Conference, costs some political power, but less for fascist nations. However, fascist nations can stay in the treaty and later decide to cheat use creative accounting to measure the true displacement of their ships, which means they have reduced restrictions while, presumably, lying through their teeth when asked about the curiously large cruisers they are building (the Head of Ship Design for the Royal Navy during the 1930s once remarked that the other side was either building their ships from cardboard or lying when presented with the official numbers for a new cruiser!).

Screenshot_8.jpg


Once world tension hits a certain level, the decisions to leave the treaty are once again available for everyone. Should any country have left the treaty, either during the initial conference or afterwards, a timer starts ticking down for the remaining countries that activates the historical “escalator clause”, which will ease the restrictions slightly, allowing even the signatories of the treaty to build more powerful ships. As a fascist country you therefore have an incentive to stay in the treaty, as it will restrict your opponents more than it restricts you while denying them the escalator clause.
escalator_clause_2.jpg

If a country outside the treaty reaches a certain percentage of the British size in capital ships, they can be invited into the treaty. Should the nation decline and continue to expand their navy until near parity, the treaty nations can try to force them to disarm up to 80% of the number of capital ships. A refusal to disarm may lead to war. If a signatory nation exceeds the allocated amount of capital ships, they immediately get a mission to reduce the number of capital ships, at the threat of major stability loss.

So you will probably want to make sure you have the most capable ships you can as you are quite limited in numbers as well as size. One of the more annoying parts of the old variant system was that a capital ship might well be obsolete by the time it hit the waves, with no chance of ever being modernized. It made even less sense in the context of the ship designer, where the upgrades between the ship classes were supposed to be more gradual. Enter the refit feature, which will allow you to upgrade your ships and otherwise tailor them better to your needs as the situation changes - from upgrading the AA on your battleships to removing one of the torpedo sets on your destroyers to make room for more depth charges.
refit.jpg


All modules have a production cost, of course, but in addition they can (and usually do) have a conversion cost as well as a dismantling cost. The conversion cost determines how much it costs to, well, convert that module from another module. This means that it is usually cheaper to upgrade, say, Anti-Air from Level 1 to Level 2 than it is to rip out the rear turret and put some AA in there. There are some exceptions to this, mostly for historical immersion: upgrading the engines is a major effort that historically required very long yard times (you basically have to cut open the hull to get the old engines out and get the new engines in, then patch it up), so it is almost always not worth it (upgrading the engines on an old battleship gets you about 2 knots of speed at the cost of a modern light cruiser), but we wanted to give you the option. As a general rule, it is never cheaper to build a lower tier and then refit to something more modern.
picture_refit_aa.jpg

If there is no specific conversion cost scripted in, you have to pay the dismantling cost for the old module and the construction cost of the new module. Modders will be pleased to hear that you can script in dismantling resource costs so you can actually gain resources back from scrapping certain components.
C_class_refit.jpg

To refit a ship, you create a variant and then select the ship you want to refit, then order it to refit to that variant. The ship will detach to go to the nearest naval base and become an item in the production queue with a few special mechanics: because it is technically still on the map, it can be bombed and damaged, which reduces build progress. If the province it is in is overrun by the enemy, it will be captured and may end up serving your enemies.
c_class_carrier_refit.jpg

You usually can’t refit between ship hulls (so a 1936 destroyer can only be refit to other 1936 destroyer variants), but otherwise you have a lot of freedom on what you can refit into what and are only really restricted by cost (for historical examples, see the Japanese Mogami class becoming heavy cruisers after being built as light cruisers). A special case are carriers, where cruiser and battleship hulls can be converted into certain carrier hulls. These are generally not as capable as purpose-built carriers, but if you have some old ships lying around…
picture_carrier_conversion_finished.jpg

Lastly, some of you have noticed that one of the German ships we showed last week looked a little different. The Admiral Scheer is at game start the Pride of the Fleet for Germany, giving Germany a small (5%) war support bonus and the ship itself some bonuses to defense against critical hits (ahistoric in case of HMS Hood, certainly) and bonuses to experience gain. It also has some interesting synergy with admirals that have the Media Personality trait: they will gain bonuses when commanding a fleet with a Pride of the Fleet in it.
Germany_panzerschiff.jpg

Assigning a ship as Pride of the Fleet is free if you don’t have one already. Changing your Pride of the Fleet costs some political power (and presumably makes the crew of the old one very sad, you monster). You can only make a capital ship the Pride of the Fleet, and you should choose wisely - losing it gives a painful penalty to war support for a while.
potf.jpg

That’s all for today, remember to tune in at 1600 hours for our stream, when we will show off some gameplay for Mexico!

Rejected Titles:

With a large enough pocket, every battleship is a pocket battleship

The Italians actually were building their cruisers out of cardboard as it turned out

What really is a heavy cruiser, anyway?

Get your discount cruisers

You can now play with your LEGO-ships even after you have built them!

Personally I think armor is overrated anyway

The C-Class Carrier Conversion has nothing on the T-Type Torpedo Transformation or the M-Model Machinegun Makeover!
 
  • 1Like
Reactions:
Retrofitting is the best part of the naval rework imo. So you mention it's possible to convert BBs etc. into moderate carriers as was done historically, but is it similarly possible to convert battleships into battleships with heightened aviation abilities? The Japanese navy did this on several BBs, namely the Yamashiro, Fusou, Ise, and Hyuuga. Finally, will it be possible to convert "convoys"/passenger ships into military ships as was attempted with the RN Sparviero?

You can refit battleship hulls into full carriers (think Lexingtons), but the Aviation Battleship isn't possible on account of it being stupid. Modders, of course, are able to change that but will have to content with my silent judgment.
 
You can refit battleship hulls into full carriers (think Lexingtons), but the Aviation Battleship isn't possible on account of it being stupid. Modders, of course, are able to change that but will have to content with my silent judgment.
Serious question, can we refit carriers back into battleships/cruisers? i.e. Courageous, Lexington
 
Also the Ibuki and, if I remember correctly, the Seydlitz. Being able to invest some convoys for a carrier wouldn't be bad either - see Kasuga Maru, Shin'you, Aquila, and Sparviero - but beggars can't be choosers.
More than a few Carriers started off as civilian ships. Jun'you and Hi'you can join that pile as well.
 
Hm. Not right now. Let me talk to some people.
I beg you: make it so. Quite a few of the carriers around in 1936 were battleship and battlecruiser conversions - it would be awesome if we could convert them back (or indeed future carriers).

It may be - for example - that battleship losses during the war mean that there's a imbalance in battleship-carrier ratio, and it may be expedient to try converting an old carrier (back) into a battleship rather than laying down new hulls.

Either way it would be cool to have, even if not everyone intends to use it. I for one would definitely convert the Lexington and Furious back into battlecruisers!
 
the Aviation Battleship isn't possible on account of it being stupid.

Aviation Cruisers worked well. The battleships... well, it was probably the best they were useful for by that point.


Modders, of course, are able to change that

Only to a very limited degree, for the same reason that they can't really do SSBNs, helis, or cruise missiles from ships to any decent degree in various modern(ish)-setting mods. Can't draw distinctions between one "carrier" configuration and another. Floatplanes and flying boats are the exact same thing as cat-and-trap deals.
 
Probably just better to build new battleships as battleships age quite quickly in HOI4 and converting old hulls from Carriers into battleship may just be a waste of resources. The probalem is that once the newer battleship hulls outrange and outspeed the older hulls the battles quickly turn onesided. Also the later battleship hulls probably have much better armor layout which make them hard to damage with anything but most high Tech guns. More slots also mean they can carry heavier AA armament which reduce the damage airpower can deal to them while making air attacks more costly.

Old battleship hulls will eventually become to weak and to vulnerable to be competitive, even with upgrades they are still probably far inferior. Like the 1940 hull Iowa class may be superior while being cheaper than the older 1936 Yamato hull and the technology difference in Equipment would likely shift the advantage even more towards the newer ships.

Light hulls and cruisers would probably be the same, the more modern hull would have better base stats and allow for more modules. The late 1940s ships and 1950 ships was simply far beyond the capability of ww2 technology. In 1940s guns started to become completely automatically reloaded which allowed for doubling more even higher fire rate. AA guns see massive improvement with proximity fuses and stuff such as 1947 40 mm gun which is wastly superior to the older 1936 40 mm. Fire Control and radar allow ships to damage their opponent from further distance and geting the first hit probably generally decided the victor because hits could often disable the radar which basically make the ship blind.
 
Last edited by a moderator:
I'm getting mental ideas similar to Stellaris's ship builder.
I love it. I'm always playing in that builder, trying to make the best Titan ship so now in HOI4; my Super-Battleships will have the same love and treatment!
 
You can refit battleship hulls into full carriers (think Lexingtons), but the Aviation Battleship isn't possible on account of it being stupid. Modders, of course, are able to change that but will have to content with my silent judgment.
What does "stupid" mean in this context? I don't know anything about WW2 ships. Do you mean it weakened the battleship somehow, that it was too difficult to build, that it didn't exist at all?...
 
What does "stupid" mean in this context? I don't know anything about WW2 ships. Do you mean it weakened the battleship somehow, that it was too difficult to build, that it didn't exist at all?...

They were barely usable as carriers because they didn't have a full flight deck. What flight deck they did have heavily restricted the heavy guns. It was a trade-off that achieved nothing.
 
@podcat @Archangel85 will you use one day a similar system for army limitation like Treaty of Versailles ? (I know that in 1936 this Treaty wasn't respected by Germany anymore but there's probably other use to be found, or at least it could be useful for modders)
yess please! but is more complicated, versalles is not only limiting (easy part) the reduce the number of existing units (dh had it, but in hoi iv is more complicate becose you have tanks that are equipment, manpower fielded, you should reduce the number of untis in fiel based in tamplates and later scrap equipment and then restrict and mybe erase tamplates) if its only limit the producction of fielding is relative easy and i didnt saw it but some psudosystem idea-event chain could control some part (getting +100000 ic cost for tanks if you field too much in peace but with out a ai backgruond it will not work fine)
 
They were barely usable as carriers because they didn't have a full flight deck. What flight deck they did have heavily restricted the heavy guns. It was a trade-off that achieved nothing.
True, but super-heavy tanks were similarly stupid - mobile artillery platforms that could not move to most places because of their weight - and they are in game.
 
Great work you have done there! I'm really looking forward to the update. But please make plane training a thing, since you do it for ships, it would only make sense to do it for planes as well.
You mentioned in the diary that scrapping ships could give you ressources. Those this mean you are introducing stockpiling for all ressources? This would be amazing and a great addition!
 
I really hope, that the DLC will come with some more 3D Models we can choose from.
Because I don't want all my Battleships look the same and the Light and Heavy Cruisers too.
It really would not be nice for an Admiral Hipper to look like a damn Königsberg-Class Cruiser! :D

But it is just immersion. The rest looks really nice. I hope we don't have to wait too long!
 
Hello, and welcome back to another exciting dev diary about ship design!

As many of you noted last week, ship design in the interwar years was heavily restricted by the Washington Naval Treaty and the First London Naval Treaty. During and after the Great War, naval planners the world over were drawing up plans for new battleships that made use of new technologies, with ever bigger guns requiring ever stronger armor meaning increasingly large ships that were becoming even more expensive. At the same time, Britain and France were at the edge of bankruptcy from the debts they had accumulated during the Great War and could not afford another naval arms race with the fairly untouched nations of Japan and the US.

The result was the Washington Naval Treaty of 1922, which forbade any new battleship construction for a period of 10 years and restricted the maximum size of ships as well as their gun armament. In 1930, the signatories of the Washington Naval Treaty came together and negotiated the London Naval Treaty, which limited the construction of cruisers and stipulated strict restrictions on their size. In early 1936, the London Naval Treaty was up for renegotiation and that, as they say, was when the trouble started.

These restrictions forced the designers of warships in the interwar period to come up with some interesting compromises, and although we can’t possibly model all the interconnected ways in which these restrictions impact design - the Nelson class baffled American designers who were trying to comprehend why the British would build a ship like that - we did want to model some of the impact and also represent the diplomatic effects of the naval treaties.

View attachment 417599

All the signatories of the 1930 London Naval Treaty will start with a national spirit that restricts the maximum cost of their capital ships. As I said last week, we originally played around a bit with tonnage as a restricting value for ship design, and obviously this would have tied in neatly with the Naval treaties, but the design was changed later to instead focus on slots and construction cost. We also thought about simulating the restrictions in gun caliber etc. through restricting modules, but in the end decided against it because it would disincentivize the player to engage with the ship designer - imagine researching a new heavy battery and then finding out that you can’t install it because it would violate the treaty! It still means that in ship design, you can’t just build the best possible ship on day one as the cost restrictions are quite harsh.

View attachment 417601

When you start the game in 1936, you will notice a mission ticking down reminding you that the Second London Naval Conference is currently underway. If you don’t decide to bail, you will automatically sign the Second London Naval Treaty. Bailing from the treaty is at first only available during the London Conference, costs some political power, but less for fascist nations. However, fascist nations can stay in the treaty and later decide to cheat use creative accounting to measure the true displacement of their ships, which means they have reduced restrictions while, presumably, lying through their teeth when asked about the curiously large cruisers they are building (the Head of Ship Design for the Royal Navy during the 1930s once remarked that the other side was either building their ships from cardboard or lying when presented with the official numbers for a new cruiser!).

View attachment 417603

Once world tension hits a certain level, the decisions to leave the treaty are once again available for everyone. Should any country have left the treaty, either during the initial conference or afterwards, a timer starts ticking down for the remaining countries that activates the historical “escalator clause”, which will ease the restrictions slightly, allowing even the signatories of the treaty to build more powerful ships. As a fascist country you therefore have an incentive to stay in the treaty, as it will restrict your opponents more than it restricts you while denying them the escalator clause.
View attachment 417604
If a country outside the treaty reaches a certain percentage of the British size in capital ships, they can be invited into the treaty. Should the nation decline and continue to expand their navy until near parity, the treaty nations can try to force them to disarm up to 80% of the number of capital ships. A refusal to disarm may lead to war. If a signatory nation exceeds the allocated amount of capital ships, they immediately get a mission to reduce the number of capital ships, at the threat of major stability loss.

So you will probably want to make sure you have the most capable ships you can as you are quite limited in numbers as well as size. One of the more annoying parts of the old variant system was that a capital ship might well be obsolete by the time it hit the waves, with no chance of ever being modernized. It made even less sense in the context of the ship designer, where the upgrades between the ship classes were supposed to be more gradual. Enter the refit feature, which will allow you to upgrade your ships and otherwise tailor them better to your needs as the situation changes - from upgrading the AA on your battleships to removing one of the torpedo sets on your destroyers to make room for more depth charges.
View attachment 417605

All modules have a production cost, of course, but in addition they can (and usually do) have a conversion cost as well as a dismantling cost. The conversion cost determines how much it costs to, well, convert that module from another module. This means that it is usually cheaper to upgrade, say, Anti-Air from Level 1 to Level 2 than it is to rip out the rear turret and put some AA in there. There are some exceptions to this, mostly for historical immersion: upgrading the engines is a major effort that historically required very long yard times (you basically have to cut open the hull to get the old engines out and get the new engines in, then patch it up), so it is almost always not worth it (upgrading the engines on an old battleship gets you about 2 knots of speed at the cost of a modern light cruiser), but we wanted to give you the option. As a general rule, it is never cheaper to build a lower tier and then refit to something more modern.
View attachment 417606
If there is no specific conversion cost scripted in, you have to pay the dismantling cost for the old module and the construction cost of the new module. Modders will be pleased to hear that you can script in dismantling resource costs so you can actually gain resources back from scrapping certain components.
View attachment 417607
To refit a ship, you create a variant and then select the ship you want to refit, then order it to refit to that variant. The ship will detach to go to the nearest naval base and become an item in the production queue with a few special mechanics: because it is technically still on the map, it can be bombed and damaged, which reduces build progress. If the province it is in is overrun by the enemy, it will be captured and may end up serving your enemies.
View attachment 417609
You usually can’t refit between ship hulls (so a 1936 destroyer can only be refit to other 1936 destroyer variants), but otherwise you have a lot of freedom on what you can refit into what and are only really restricted by cost (for historical examples, see the Japanese Mogami class becoming heavy cruisers after being built as light cruisers). A special case are carriers, where cruiser and battleship hulls can be converted into certain carrier hulls. These are generally not as capable as purpose-built carriers, but if you have some old ships lying around…
View attachment 417610
Lastly, some of you have noticed that one of the German ships we showed last week looked a little different. The Admiral Scheer is at game start the Pride of the Fleet for Germany, giving Germany a small (5%) war support bonus and the ship itself some bonuses to defense against critical hits (ahistoric in case of HMS Hood, certainly) and bonuses to experience gain. It also has some interesting synergy with admirals that have the Media Personality trait: they will gain bonuses when commanding a fleet with a Pride of the Fleet in it.
View attachment 417611
Assigning a ship as Pride of the Fleet is free if you don’t have one already. Changing your Pride of the Fleet costs some political power (and presumably makes the crew of the old one very sad, you monster). You can only make a capital ship the Pride of the Fleet, and you should choose wisely - losing it gives a painful penalty to war support for a while.
View attachment 417612
That’s all for today, remember to tune in at 1600 hours for our stream, when we will show off some gameplay for Mexico!

Rejected Titles:

With a large enough pocket, every battleship is a pocket battleship

The Italians actually were building their cruisers out of cardboard as it turned out

What really is a heavy cruiser, anyway?

Get your discount cruisers

You can now play with your LEGO-ships even after you have built them!

Personally I think armor is overrated anyway

The C-Class Carrier Conversion has nothing on the T-Type Torpedo Transformation or the M-Model Machinegun Makeover!
Funny, that I can easily imagine sinking an AI pride of the fleet over and over, thereby really messing with their war support. When you build and deploy a capable fleet, the enemy loses ships like there is no tomorrow.