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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.

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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!).

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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.
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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.
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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!
 
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Now you can put a maximim of 5 naval factories for heavy ships in a single line. So as far as I know Australia can build one battleship or carrier just as fast as the United Kingdom, the only advantage of the British is that they can have more production lines and build more battleships at the same time.
Make me thinking if there should not be any other limitation to building battleships such as a minimum amount of total factories.
 
Make me thinking if there should not be any other limitation to building battleships such as a minimum amount of total factories.

You have some kind of limitation in the fuel usage of a Battleship. Small nations such as New Zealand or Denmark should not have the capacity to maintain several battleships or carriers.

Even Japan with all its power could have all kinds of problems to maintain their heavier ships.

You also have tech, I suppose that you have to invest in better guns, better radars, better armour. When you're Mexico with only two tech slots is difficult to research all of this
 
i see vary hard dominions could build more than a cl
 
i see vary hard dominions could build more than a cl

Building a Battleship would be ruinous, but possible for the best of them. For example, Canada had six destroyers, four minesweepers and a few auxiliar ships in 1939.

By 1945 Canada had more than 400 ships, most of them small corvettes and destroyers made to protect convoys but still quite the large fleet.

I think a minor with such industrial power as Canada could build a pair of good battleships if they wanted to. Now, not only the supply requirements of those behemoths are quite big, but also their construction would take recourses that would see better use elsewhere (even in-game)
 
400 cheap ships may be alot cheaper than a couple of battleships.

Corvettes were cheap (Flower class corvettes were about 90,000 pounds) but not that cheap :). A KGV class BB cost about 7,400,000 pounds, which comes to about 82 Flower class corvettes (of which Canada actually made 114), and Canada also made the larger Castle class corvettes (12 - I'm afraid I don't have a cost) and River class frigates (70, at least 240,000 each - more than the value of two KGVs all by themselves)).

That said, it's more than a question of cost - developing the plant to build the armament, armour and machinery from scratch is a lot of effort, and it's much easier to scale up to corvettes and frigates, than it is to BBs and aircraft carriers, but in ways that aren't fully captured in cost (the first KGV built in Canada, if it was their first BB, would likely cost far more than 7.4 million pounds because of the steep learning curve involved).
 
I think there is also a question about their role in the war. If the first objective of Canada was to help Great Britain with the battle of the Atlantic then 80 corvettes had more strategic value than a single battleship.

Anyway, what you say is true. But for good or bad reasons the game does not handle that level of detail. Here a factory can build submarines, battleships and destroyers just the same
 
I have a few questions about the capturing of ships, will that apply for any ships that are in port using dockyards for oh say repair? Cause a ship that is having its broken propulsion system replaced shouldn't be able to escape. And will there be an option for germany to attempt to seize the french fleet after the armistic, as they planned to do that before the british decided to prevent this from happening. Lastly, when a peace deal comes around, will we be able to acquisition our defeated foes boats, or will the only way to retain a nations navy be to puppet them?