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HOI4 Dev Diary - New Naval Combat

Hi everyone! Since forums were all down yesterday the diary is coming today instead :) Today we are going to look at core changes to naval combat coming in 1.6 Ironclad. We have already discussed how missions are changed as well as basics of the new spotting system in a previous diary and a future one will be fully dedicated to submarines so I will only cover them a little for how the interact with regular fleet battles today. So lets charge in!

Its best to start by looking at problems in the old system so you can see how we have tried to solve them and iterate. We identified the following:
  • Battles are extremely decisive so tiny mistakes have bad consequences
  • Combats tend to snowballs as everyone and their mother’s fleet pile in
  • A big fleet was always better, together with the above point promoting doomstacking
  • The interface gets very confusing as ships close with each other. Distance overall is very hard to show and balance.
  • It is easy to miss a combat happening while busy elsewhere.
  • Its “simulation nature” made balancing an incredibly hard problem. Resulting in things like the all-battleship fleets performing well.
“Battle-lines”
battle.jpg


To deal with distance and screening issues we have split up the battle in 4 areas per side to represent position and distances.

Screens - Your screen ships go here. Screens are the closest to the enemy and protect the ships behind them (details below).
Battle line - This is where your big guns sit. Heavy cruisers, Battleships etc. Anything with heavy long range guns. These guys also help to protect carriers and convoys behind them.
Carriers - Furthest back are carriers protected by the other two lines. This is also where convoys will be if part of the combat (say during invasion or a convoy raid battle).
Submarines - Under the sea. This area is actually two as we separate located submarines (which can be engaged with depth charges) from unlocated submarines.

By splitting things up in discrete distances unlike the old system we can more easily capture the impact of distance and positioning, and keep it easier to see what is going on at a glance.

The area they are assigned to depends on the weapons they have, which makes things tie in neatly with the ship designer. Rules for combat are now largely depend on how different weapons interact with the areas, so it is important to go over them before we continue. We also show these summarized at the top of the combat screen for quick information and to help you evaluate the combat situation:
stats.jpg

Light Guns - These are smaller caliber guns. The armament on destroyers/light cruisers and secondary armament on heavier ships. Their job is to hit and kill smaller fast moving ships. They generally do not have the armor piercing to lay down serious hurt on capital ships. Light guns attack ships one line over. So screen ships can shoot other screen ships, and when there are no more shoot the enemies capital ships. Capital ships with secondaries can fire from behind the safety of the screens at the enemy screen.

Heavy Guns - These are hard hitting armor piercing guns designed to take out big ships. They have trouble hitting small fast ships, but when they do it is for significant damage. Heavy guns have the range to fire over one of the enemy lines. So they will be hitting the enemy battle line even if it is screened.

Torpedoes - These are the big capital killers. They ignore armor, and have big damage but are terrible at hitting fast/small ships. Torpedoes can hit any line as long as it is not screened properly. So if your screening is down to 50% then half of the enemy torpedoes can be fired at your battle line, and if the battle line is also weak some torpedoes can slip through and hit carriers or convoys.

Anti-air - AA works a bit different. When firing back at enemy planes a ship will also get a part of the fleet’s AA armament to help it, so it’s quite nice to make sure your support ships (or battleships if you focus on carriers) are stacked with as much AA as possible.

Depth Charges - This is the only weapon that can hurt subs, and it only works versus revealed subs.
Carrier Planes - Carriers can carry different kind of planes. Naval and dive bombers help attack other ships and fighters help protect yourself. The whole air model in naval combats is now more in line with the rest of the game and takes place in the airzone as you would expect. So can now be disrupted etc. This fixed a bunch of issues we had with the interaction between land based air and carriers.

sub.jpg


Next to the weapon summaries we also display the side’s positioning value. This is a value simulating how well positioned your task forces are. A low positioning could for example mean that all your screens are scattered in a storm and your capital ships are wide open to attack. Positioning affects screening directly and a low value will directly hurt the fighting abilities of the ships as they wont be in optimal range, have another ship fouling the range etc. A big effect on positioning is the relative sizes of the fleets. So the bigger fleet will have an inherent penalty to its positioning versus a smaller, more easily controlled force. An admiral’s maneuver skill helps with this though. There are also traits like Lone Wolf and the Capital Ship Raiders tech from the Trade Interdiction doctrines that help increase this penalty for the enemy. The idea is to make smaller capital raiding forces more competitive if you tech right and have a trained Admiral in charge.

screening.jpg


Tooltips for ships now give great breakdown on where the damage is coming from so you can see how well (or not) a particular weapon type is doing, there are also totals summarized in the top of the interface.
dmg.jpg



Entering and exiting combat
After the initial battle starts, further task forces can join. When they do they get put in the “Incoming” box, much like before. The time spent there depends on their org levels. The lower the longer they have to wait to join. Org is affected by moving, but also by giving manual orders to fleets (we want you to plan ahead, not react for max efficiency). Whenever ships are called to a combat, they will take an organization hit, which slows down their joining. Similar delays also apply for missions like convoy raiding or escort at suboptimal efficiency so it’s harder to bring all your power to bear at the same time.

On the flip side, if you take out the enemy side before the incoming ships arrive, the battle ends and you can run away (or the sides have to re-spot each other if they still want to fight), the idea is to help subs and other raiders out by allowing fast hit-and-run battles.

run.jpg


As for exiting combat that is both something you can order directly and something that happens when ships take enough damage (remember, you set up aggression levels to control how risky you want your task forces to be). Retreating is a process that takes some time. It is affected by doctrines, traits, weather, terrain, and the speed of the ship. We show it as a progress bar so you can bite your nails as the enemy pride of the fleet slowly gets away. Note that we also now have critical hits which will slow down ships and making it harder to run - a ship with a jammed rudder has a wooping 90% penalty to escaping. Escaping is an important part in keeping battles from being too decisive.

This is also where submarines come in. They follow normal torpedo rules, but also free to circumvent them when it comes to escaping ships. So if you have subs hiding in your battle they can engage the enemy capitals as they start to run (of course this reveals them, depending on doctrine levels, leaving them open to return fire from anti-sub vessels).

See you next week for a look at submarines :)

image.png


Rejected Titles:
- Sinking inside the box for a change
- Bravely retreating in the face of underwhelming odds
- Man, those guns!
- "Stop writing dumb titles and post already podcat!"
 
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if daniel doenst stop and look a complete naval engagement i gonna go creazy!
 
Big fan of the critical hit weighing against escape concept. I'm not looking for every battle to be decisive, however, if a certain enemy tub is barely afloat, I have a hard time watching it consistently evade pursuit. So bring on the jammed rudder mechanic. Good step in the right direction!
 
Question for the Dev's:
Will the new naval combat allow plotting naval invasion routes?

I recently invaded Nagasaki from Taiwan, and the invasion plotted all the way around the north end of the island of Kyushu, traversing all of the seas adjoining the island.
Is there a current way to correct the plot?
 
Speaking to this: unless it was early war American or British carriers which cruised in independent formations rather than jointly as a battlegroup, it would be really hard to "target" a single ship. As the war continued, the benefit of multiple carriers "sharing" a ring of AA cruisers/destroyers and their accompanying CAPs became obvious.
No it didn't. Different navies actually had different doctrine. In the battle of Midway, for instance, IJN carriers sailed far away from each other, so that attacking planes sometimes spotted one or two, but never all CVs. IJN also didn't employ close ship formations for AA sharing, but actually kept capital ships away from each other to allow for free evasive maneuver. USN used a much closer formation with mutual AA support. CAs were certainly not the only factor in AA, there was much more AA in BBs and DDs also had significant AA impact.
Anyway, naval doctrines would be a cool mechanic to actually impact how naval war functions: if you go the IJN route, then all ships get much better evasion, but much less mutual AA support, while for USN it would be the other way around. Historically there was no one perfect way, each doctrine had advantages and disadvantages.

I'd imagine that targeting should be focused on what the attackers can "see" rather than getting that nitty-gritty. From my reading, Japanese pilots (for example) didn't care what ship they were necessarily attacking, just that they attacked the ship... which is why those picket destroyers were really pummeled.
IJN pilots were very good (until the highly trained ones got killed) and they were certainly capable of following orders. Your statement is wrong and possibly influenced by the difficulty of locating capital targets in the vast ocean. If you got a flight of dive bombers and there's no carrier in sight and you got to turn back due to low fuel then it's better to drop the bombs on the lone enemy CA than into the empty sea.

I'm a bit afraid that including submarines into the naval battle mechanics will produce weird and non-historical situations. Subs were not parts of ww2 battlefleets due to their low speed. They could not keep up with the rest of the fleet. Also, due to their low speed they were seldom in the right place at the right time. There were attempts to lay ambushes with subs but fast battlefleets with screen DDs usually avoided those easily. Subs should be lurking for passing ships and there should be a low chance to hit capitals, which should be much lower when they are screened, but they were mostly hitting slower merchant shipping. In any case subs were not part of the battle line.
 
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Also as a player with over 1000 hours in HOI4, I really hope AI naval invasions will be fixed. So far AI does moronic pointless invasions, wasting huge resources while landing dozens of divisions into provinces with no logistic support, where they can be encircled and destroyed at ease. Mines are a welcome addition, but I hope that the AI won't simply throw it's troops into minefields, but do something more historic and focused.
 
you need 4-1 ratio screens for max efficiency
I am surprised. This was posted in December. until yesterday the wiki said 3 to 1.

edited to add:

hoi4 wiki
page: Naval_warfare
section: Strategy Fleet Composition
first line, now that I edited it
"Have 4 screen ships for every capital ship in a battle fleet."
prior to my edit last evening
"Have 3 screen ships for every capital ship in a battle fleet."
 
Man i hate looking back at this after thousands of hours of modding and realizing you've literally met none of your development goals to fix, and you've left out so many possible defines to fix it. Doomstacking is still, and always has been the meta, positioning is flawed and impossible to fix due to lack of defines, such as a submarine fundamentally counting towards the same positioning penalty as a battleship and no way to mod that(lol), to removing the old define for how many ships can engage each other at once when you relased this new dlc. I mean come on, how can you say you're trying to make navies realistic and remove doomstacking and then remove important defines like that, and leave out crucial modding support for all the others. And as for one sided battles, that isnt fixed either! There's 3x the modifiers, and 10x the amount of SWEAT that can go into creating a ship with modules now, and soft exploiting maximum values like light attack and speed, both of which are absolutely broken in the base game. And you never touched the sea zones or how they fundamentally function with large fleets, so you're going to have two player doomstacks in a single sea zone, why not make it so multiple little battles could take place instead of a giant one if this is going to end up being the result? If you made it so your smaller realistic fleet could engage in a smaller battle with PART of the 200+ ship ARMADA that the average UK player doomstacks, that alone could fix major underlying problems with naval combat in hoi4. It's just depressing, i really don't even care for a discussion, i just felt like posting this. At the very least if a developer sees this, maybe they will add back in a gangbang define for ships that was there when the game came out after they are done finishing up their Estonian focus tree....
 
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Thank you for writting this, reflection is important and the original goals should not be forgotten, there are so many good ideas in that diary and a lot of potential, its just sad for all of us who enjoy the naval game to see the state its in now.
 
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