Hi everyone, welcome to another dev diary! Last week we talked about changes to frontlines (both UI & backend and AI) and today I want to talk about some of the other fixes and changes we have been up to.

1.7 ‘Hydra’ is a chance for us to rewrite and improve some pesky systems and to step up and go 64-bit, so this diary is going to get a little technical

64-bit
1.6.2 will be the last 32-bit build of HOI4 and we will be leaving it (and older as normal) on steam for those who still want to access it (and make sure to mark the build). We also will not be converting any of the old versions to 64-bit. It would simply be too much work. Because of this we have decided to up the big decimal on our version number to 1.7. 1.7 ‘Hydra’ will be fully 64-bit supported on Linux, Mac and Windows and it has been a big undertaking. There are many reasons for this change. Some platforms like Mac are phasing out 32-bit quite aggressively and we don’t want to end up with people not being able to play on there. 64-bit lets us use newer compiler features and a lot more possibilities code wise in the future. It is also about time, because it felt like a lot of the industry did this over 5 years ago

As a player you won’t notice a huge difference. We haven’t seen any big performance improvements for example, although I wouldn’t say that it’s impossible some areas might improve as our investigations have been pretty shallow. 64-bit is tricky in that on one hand we get access to the possibility of more optimized code, CPU registers etc, but it also takes up more memory, and memory is often highly impactful on speed too. We see it as an investment into the future where we know we can start taking advantage of things now that the foundation is in and make it easier for us to work.

We have already seen some of this internally where we during this work have been able to replace a lot of basic code structures dating back to the Year of our Lord 2003

Convoy system
The old code system keeping track of your favourite little boats has long plagued development, and after 1.6, when we still had some issues, we decided it was simply best to take it out back and shoot it. 1.7 comes with a new system rewritten from scratch. The old convoy system was operating in a way where everyone could control it, and by association, everyone could also break it at any time. It would also swap convoys in between the country’s supply and the assignments at every single tick, swapping them around all the time, and convoys getting lost because there was no sense of ownership and control over the convoys. It was a nightmare.

The new system is a centralized system where each country has one instance of a class that has full ownership and control of convoys, and any other gameplay code that needs convoys can request them from this system but never have real control over them. This “magically” fixes bugs with convoys disappearing from the game because it’s not possible to write code like that anymore. It’s stability by design along with the other great and exciting stability changes that we are bringing to you with this patch.


Naval Balance Changes
We have been looking at convoy escorting, subs, detection and raiding and making improvements:

• Subs can now fire also while withdrawing
  • Convoy escort missions were too binary. Either you have protected the convoys in time or not. Arriving on time provided too much of an advantage to the escort and thus made sub raiding less viable. Subs will now get an extra volley or two in most combats, making raiding with high-quality subs against low-quality escorts more viable.
• We increased submarine detection chance from passive detection (hi bitmode) and lowered detection chance from firing torpedos. Detection chance from passive sweeps now scales parabolically so that large differences in detection and visibility will be much more pronounced.
• We gave carriers passive sub detection and gave them a detection increase in doctrines. This makes them more viable in their historical roles in the Atlantic.
• We also increased detection values on some later radars and a bit on sonar, to make detecting subs a bit easier.

We have also been looking at various issues related to convoys and how they defend themselves against naval bombers. There were many different problems:

• Unit transports died too easily vs naval bombers, this was extra bad for the AI which generally suffered more to this than a player would.
• In small naval bombers vs transports as above, we also had way too high casualties for the planes
• Because convoys are not “real” units they would heal up after battle, so unless you sunk them there was no real damage to the enemy.

To deal with this, we have made several changes:

• Troop transports get a special defensive boost in the particular case of being attacked directly by naval bombers
• The anti-air formula for ships shooting back has changed so that partial damage is taken into account. We now essentially roll a dice for partial damage allowing it to kill planes. Before, weak ships like convoys that got hit a lot had much to big an impact, and early naval bombers didn't really deliver. This should be a lot nicer now.
• At the end of battles we add up all the damaged convoys and for a fraction of them we roll a dice based on the damage to see if they sunk from that damage. The kills get attributed to the last to strike them during the regular battle.

When it comes to regular combat we wanted to help out carriers and capital ships a bit and we felt the more realistic way of doing that was to give them a time at the start of the combat when they are the only ones active. Carriers and aircraft are active straight away. Some ticks later capital ships and subs get to fire and last screens. This gives a bit of a boost to those bigger ships and represents their longer ranged weapons better.

Script-Side Performance Improvements
1.6 came with a number of new script features to improve performance for targeted decisions. Previously these decisions would check every country in the world every day, and with some of the more complex triggers that could amount to quite a bit of number crunching. With the new features, we can pre-restrict the list of targets to reduce the necessary number of checks. Unfortunately, the new script features came too late in development for us to utilize these features in the initial release and other bugs took priority.

Thankfully, a member of the community by the name of Antoni Baum (aka “Yard1”) did make the effort to go through our script and fix all the places where the new features would make a difference (as well as a few triggers where a small reordering of script checks resulted in better performance). This work has been merged into 1.7 with permission. While it is difficult to measure the immediate performance effect of these changes, we saw a performance improvement of about 5-10% depending on the overall gamestate, number of wars etc.

We planned to put 1.7 out as an opt-in beta tonight but we hit some snags (which is why this diary is a bit late ) but we think we should have the open beta tomorrow with patchlog for those brave enough to help us test it

See you again next week!

 

[Pandia]

It got removed in MtG didn't it?

Yes, they removed the Super Heavy Battleship II

 

[Axe99]

Channel Dash, when Scharnhorst, Gneisenau and Prinz Eugen in 1942 sailed thru the English Channel without losses, shows that sometimes land-based fighter cap gives good protection. But that was a rare occasion.

It also outlines the situations where it can work.

Land based CAP could be successful when:
- Planning and coordination before.
- Enemy not being aware.
- Very short distances with ships basically hugging the coast.
- Short fast operations since it lacks endurance of Carrier CAP.

I'm not entirely sure it was in place by then, but I wouldn't be surprised if Germany didn't have some radar directed fighter-direction capability by that stage (the definitely did by 1944). Radar and a system for using it to direct land-based fighters made a huge difference to the effectiveness of land-based air cover. It still wasn't perfect, and there could still be gaps in the cover when different flights were 'changing the guard' (particularly when there were substantial distances from the airstrip used for the air cover), but prior to radar-directed fighter control, land-based air over ships was borderline useless.

 

[Parabola]

It's concerning seeing reports of strange Ai behaviour in historical mode. Seen several people saying Romania is joining japan's faction rather than Axis. And some saying Germany not declaring on USSR and others saying British AI doing odd paths. Hope it's all fixed before patch goes live or else i'll have to wait til 1.7.1 or 1.7.2.

 

[kentsfield]

If your land based fighters have fuel to stay in the air for say 7 hours and need to spend 3 hours hours flying to the taskforce + 3 hours to get home they will struggel to maintain an effective aircover due to needing ~8 fighters for each one fighter that is permanently in position ( assuming 1 hour lost for cycling planes or combat fuel ). That is also assuming the land based fighters are able to locate the fleet at all and that the admiral of the fleet is willing to restrict their movement to stay within range.

Again, air forces were willing to go through that effort to protect strategic bombers. If they were willing to protect bombers that could be churned out once every hour on an advanced production line, they should certainly be willing to protect ships that took years to construct.

​

A good historical example of the efficiency of land based air cover / CAP is the sinking of Prince of Wales and Repulse. Not a single of the land based fighter tasked with protection of the fleet appeared until after the attack was over and the ships were sinking.

Now you're just being disingenuous. Ten obsolete Brewster Buffalo fighters are not what I would call robust air cover. They certainly weren't going to deter much of anything even if they had arrived.

- Very short distances with ships basically hugging the coast.

That was dictated by the poor range of Bf 109s, would have been different if they had a large quantity of P-51Ds instead. Also, not every naval battle in HoI 4 has to take place on extreme ranges on the vast sparseness of the Pacific.

 

[Goliathe]

It got removed in MtG didn't it? (unless you use console commands to unlock all tech)
The idea being it's a choice between powerful early but no upgrades vs. eventual supremacy IIRC

The super heavy battleship still gets engine uprades from the regular battleship. In previous editions SHBS II was extremely overpowered if you had a single 100x battleship research bonus. Research the super heavy, and then you can go 100% to get the heavy II incredibly early.

The SHBS still a strong ship by the way.

 

[Alex_brunius]

That was dictated by the poor range of Bf 109s, would have been different if they had a large quantity of P-51Ds instead. Also, not every naval battle in HoI 4 has to take place on extreme ranges on the vast sparseness of the Pacific.

Why not show us a historical example then of a Taskforce far out at sea that was successfully defended by land based fighters against enemy air attacks?

Surely there must be loads of examples from history if it was as easy as you claim!

 

[kentsfield]

Why not show us a historical example then of a Taskforce far out at sea that was successfully defended by land based fighters against enemy air attacks!

Because the only potential examples would be Japan against the US, and Japan was foo inept in too many categories to be a valid comparison.

The closest comparison to make is the strategic bombing campaign over Germany. There you had scrambling German fighters that were decimated by long endurance fighters that faced the faced the disadvantage of hostile radar and AA

 

[Alex_brunius]

Because the only potential examples would be Japan against the US, and Japan was foo inept in too many categories to be a valid comparison.

Not true. Both UK and Germany as well as Commonwealth minors operated fleets far from shores fairly frequently as well as Japan and USA. Especially for UK which already had a global network of bases and the best fighter directors/radars in the world such a doctrine of land based air for fleet air defense must have been very promising if it could have worked.


Instead UK relied on Carriers for fleet air defense and gave them the best armor, fighter direction and early warning air radars they could get their hands on.

Despite closing the airgap in the Atlantic with long range bombers in 1943 the allies choose to build hundreds of escort Carriers to bring airsupport and airdefense directly to the convoys where it could quickly respond.



Comparing to strategic bomber escort is a relevant compairson the day the battleships that should be escorted take off from the same airbases, moves at 200+ knots and have limited range which is comparable to long range fighters with droptanks when heavilly loaded.

 

[donofwar3]

So playing Red Skull organization China still sucks Japan still kill that Sino war. AI USA cant hold nothing. The Pacific war Japan a beast in that. U.S.A Still Sucks. D-Day is a joke. The Order of Battle is terrible. that need to be address. For some Reason Germany population can surpass Soviets even thought there fighting on many fronts. It probably different if you playing as Germany. Still the game has unit spamming. to much axles buff. Hail Hydra 1.7

 

[Captured Joe]

How disappointing.

Have you noticed any improvements in the game's performance (particulary late-game)?

 

[Axe99]

Not true. Both UK and Germany as well as Commonwealth minors operated fleets far from shores fairly frequently as well as Japan and USA. Especially for UK which already had a global network of bases and the best fighter directors/radars in the world such a doctrine of land based air for fleet air defense must have been very promising if it could have worked.

(I'm agreeing with you here in case my comments ambiguous at face value, although they shouldn't be)

One other thing to consider about the disadvantages of land-based air cover is the time taken to react to changing situations. Even with the best radar-directed fighter control, if the fleet is 45 minutes away from the supporting airstrip, then if an unexpectedly large strike comes in, then there's nothing to be done, while carrier-based airpower can be a bit more flexible (noting that it's not trivial suddenly launching more planes than planned, but iirc carriers often had a number of fighters 'ready to go' in case of trouble if they were in a situation where it might be expected, and there weren't other landing or launching operations going on).

While HoI4's mechanics don't surface the concept that clearly, an aircraft with 300km range is only going to spend a tiny amount of time at the 300km point, and most of their time flying to and from it (and actual air combat burns fuel pretty quickly) - so land-based air needs to take off, form up, travel however far to the fleet, find the fleet, and be linked in with the fighter controllers of the fleet (and another factor - carrier-based air is likely to be far more experienced at working with the fighter controllers than aircraft from a land base that the fleet just happens to be sailing past). The time to react to new information or changing situations is far less, and the number of aircraft needed to maintain a CAP was lower (and the safety of the aircrews, who are more likely to ditch near ships in the case of technical problems with their aircraft, was higher).

Carrier-based air takes off and even if they haven't formed up yet, they can usefully intercept incoming aircraft (although until height-finding air-defence radar shows up, there's still the chance they may not be at the right altitude - but that's an issue for land-based air as well).

 

[xtfoster]

It's concerning seeing reports of strange Ai behaviour in historical mode. Seen several people saying Romania is joining japan's faction rather than Axis.

That has been possible for a long time now, but does seem to happen more often. Basically, when Romania gets to the point it can join a faction, it looks for one with the same ideology (Fascism). At that point there are 2 (Japan and Germany) and if neither asks them to join it will pick one and ask to join.

 

[VitaminK]

How disappointing.

Have you noticed any improvements in the game's performance (particulary late-game)?

Think we'll have to wait and see, OP says minimal seen in their testing but that their testing was pretty limited.

 

[pete_ts]

Hail Hydra!

 

[uberjedi]

Is the beta available yet?
I cant see it in Steam.

 

[uberjedi]

Nevermind. I found it.

 

[kentsfield]

Not true. Both UK and Germany as well as Commonwealth minors operated fleets far from shores fairly frequently as well as Japan and USA. Especially for UK which already had a global network of bases and the best fighter directors/radars in the world such a doctrine of land based air for fleet air defense must have been very promising if it could have worked.

Neither the Commonwealth or Germany had aircraft with sufficient range, combat performance and quantity to even attempt it.

Despite closing the airgap in the Atlantic with long range bombers in 1943 the allies choose to build hundreds of escort Carriers to bring airsupport and airdefense directly to the convoys where it could quickly respond.

Yes, I get you want to have an exact replay of history, but my central point is that decapitating the CAGs of a carrier group with land based fighters should be a plausible strategy. Don't distract from that.

an aircraft with 300km range is only going to spend a tiny amount of time at the 300km point, and most of their time flying

That might be a limit on biplane relics from WW1, but the range of late and post war aircraft dramatically increases from early WW2 aircraft.

e.g. :
La-11: 2235 km
Mig-15: 2520 km
F-82: 3650 km
P-51H: 2465 km
CF-100: 3200 km
Vautour IIA: 5400 km

Such ranges clearly influenced Soviet thinking into placing a low priority on carriers as land based air could cover much of their needs.

 

[SlinkyTWF]

Naval coordination with land-based air was abysmal throughout the war. One chief reason that is being overlooked by some: to make this happen, the fleet has to be in constant radio communication with the airfields and CAP. The next thing you know, your TF is besieged by enemy forces who now know exactly where they are, and at the range needed to maintain land-based CAP, your bingo fuel level is too low to be of mush use (even in a P-51). Therefore, it did not happen, and if it did, it was the exception, not the rule.

 

[Axe99]

That might be a limit on biplane relics from WW1, but the range of late and post war aircraft dramatically increases from early WW2 aircraft.

e.g. :
La-11: 2235 km
Mig-15: 2520 km
F-82: 3650 km
P-51H: 2465 km
CF-100: 3200 km
Vautour IIA: 5400 km

Such ranges clearly influenced Soviet thinking into placing a low priority on carriers as land based air could cover much of their needs.

Even if (and it's a big if) the training and protocol can be put in place to ensure that the aircraft find the fleet and know how to operate effectively with it, that doesn't take away from the point that you're spending an awful lot of flight hours in-transit, and that the air cover reaction time is however long it takes to fly from the airfield in question.

It's true that in the post-war environment the USSR (which initially post-war effectively had a coast-defence navy, even if it aspired to more) could rely on land-based air coordinating with local forces (the USSR inherited a coast-defence navy mentality from its doctrine in the 1930s, although Stalin's battleship fetish confused this a bit, and also influenced post-war Soviet build programs until his death in (I think - going from memory, but around then) 1954) but this isn't much help at all for power projection (and carriers are a power-projection tool - if you only want to defend your coastline, you don't need them). Say, for example, you want to send a fleet into the Central Med as the USSR? Your air power is either carrier-based, or it has to come from Sevastapol or similar, a distance of 1500-odd km. The ranges you've quoted above are almost definitely 'optimum ranges in optimum conditions', and you'll find 'effective combat radius' figures are likely to be far smaller (as the weather may not play ball, and the aircraft may want to get to the conflict zone at faster than cruising speed, burning fuel inefficiently - once in the combat zone, it's pretty much guaranteed aircraft won't be burning fuel at cruising speed rates but rather chewing through it much more quickly).

For example, and I'm taking these figures from Shattered Sword, while the range of an A6M2 Zero was 1,675 nautical miles (page 479), the book quotes it as being able to 'operate as far as 300 miles from the carrier'* (page 78, both figures are with drop tanks). Further, it's maximum speed was 331mph. So if there's an incoming strike against a fleet 300 miles away, even if it as the juice to travel that far and fight at maximum rather than cruising speeds, it's going to take an hour to get there and spend a very large proportion of its time airborne travelling to and from the fleet, rather than providing actual air cover. This second point is important - say your La-11 has a combat radius (as opposed to optimum maximum range) of 500km, its top speed of 674km (taken from a quick-and-dirty look at wiki, sorry if this is off) means it'll take 45 minutes to get their from the airbase, and at tat distance is unlikely to able to spend much time actually over the fleet - so for ten fighters on a carrier with the fleet, you might need 50-100 fighters at an airbase to achieve the same level of coverage. Should those fighters become damaged and unable to make the flight back to base, rather than being able to land on a carrier they may well have to ditch, losing the aircraft altogether.

I do agree a fleet in a coastal zone should be able to be put under serious pressure by land-based air, but I was under the impression it could (but am a little distracted from HoI4 atm, I'll be back playing it soon, but I don't only play one game, and if you're seriously into ships, there was another release in the last couple of weeks that may have got your attention ).

* Source not clear on whether nautical or not, hopefully it is.

 

[obren]

Carrier-based air takes off and even if they haven't formed up yet, they can usefully intercept incoming aircraft (although until height-finding air-defence radar shows up, there's still the chance they may not be at the right altitude - but that's an issue for land-based air as well).

Pre-radar, that is not at all certain, especially against dive-bombers. The Japanese carriers at Midway launching extra fighters to combat the dive bombers failed to get in position in time to disrupt the attacks, while late 1930s Royal Navy thinking assumed that fighters could not intercept attacking bombers in time, and hence lead to powerful AA and armoured decks for those carriers designed for the European theatre. The 1941 attack that crippled Illustrious illustrated the point despite her having radar, the Ju87s were detected only 28 miles away and like Midway the CAP was out of position attacking torpedo bombers, while the relief fighters ready for launch were too late to intercept.

I do agree a fleet in a coastal zone should be able to be put under serious pressure by land-based air, but I was under the impression it could (but am a little distracted from HoI4 atm, I'll be back playing it soon, but I don't only play one game, and if you're seriously into ships, there was another release in the last couple of weeks that may have got your attention ).

I would suggest that land-based air not trained to operate in anti-ship missions are overstated in HOi4.

A contentious example is the Luftwaffe's failure to stop the Dunkirk evacuation, with the anti-shipping trained units being much more successful than the standard bomber units. The arrival of land-based fighters in time to watch the main units of Force Z sink beneath the waves is a classic example of land-based defence never being in the right place at the right time, while the successful Japanese bombers were specially trained in anti-ship operations. Operation Cerberus is an impressive example of a successful defence due to excellent organisation and training, but I suggest is an exception rather than the rule, and at least partially due to it being a special operation rather than part of an ongoing campaign. The Regia Aeronautica was of limited effectiveness against the Mediterranean Fleet, with their SM79/SM84 Torpedo Bombers being the stand-out performers during the war by actually achieving some success. The RAF supporting the Eighth army was not all that effective at stopping Axis supply ships when you compare them to the strike rates on Axis transports by the small numbers of FAA Swordfish operating from Desert aerodromes. Another interesting case is the USAAF operating from North Africa trying to intercept and sink Axis transports reinforcing Tunisia - they basically failed to achieve much until they teamed up with the FAA, which dramatically increased their effectiveness.

I suggest that a fleet operating in coastal waters is in not that great a danger from air units that are not trained in anti-ship operations, but are at serious risk from units that are. Even if you look at the more modern example of the Falklands War, the Argentine aircraft that were most lethal to the Royal Navy were the most antiquated Skyhawks in the Argentine arsenal, but as they were trained to operate from the Argentine carrier, they were specifically trained for anti-ship strikes, unlike the other squadrons that had been re-deployed from inland airbases.

I am playing a HOI4 1.7beta test game as Germany and after the fall of France I was sinking 1+ destroyers each and every day in the English Channel for a couple of months while I prepared SeaLion. The attacking aircraft were 200 Naval Bombers, with an additional 800 Medium Bombers added later (that basically doubled to tripled the slaughter). That is far more effective than the actual Channel Convoy attacks in the opening phase of the Battle of Britain.

If we assume that torpedo carrying medium bombers such as the He111H6, G4M Betty and SM79 are represented by Naval Bombers, then I contend that HOI's Medium Bombers are overstated in their anti-ship capabilities and find naval targets too easily. The Fliegerkorps X Ju87s that attacked Illustrious were a specialist anti-shipping unit, and maybe would be better represented as carrier based dive bombers rather than CAS to illustrate their specific training, in which case the land-based CAS' ability to find naval targets is also rather overstated.