Dev Diary #8 - Naval Combat - 29.October 2009

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  • Hearts of Iron III
Welcome to this weeks issue of our AoD Development Diaries.

Today’s topic is Naval Combat and what we’ve changed and added in the maritime area, as well. Before I go into the changes of the combat system, let me tell you that we added a new unit class, called heavy subs. They are buildable around 1939-40, and try to model the large Japanese submarines, some of which were capable of carrying up to 3 airplanes (some may have already heard of “submersible carriers”).

In fact, this is a very neat special unit with mostly better overall stats than regular subs and a huge range of operation, which gives you opportunities to operate early in the game in faraway parts of the world.

In terms of interchangeability between regular convoys and transports, destroyers and escorts, we made them in one way convertible. You can now always choose to use your DDs or TPs in regular trade relationships. But once they are converted, you won’t get them back.
To avoid exploits we integrated some conversion rules: how many escorts you get from one destroyer flotilla depends on the current tech level of the destroyer. So you will, for example, get 1 Escort from an old fashioned DD-1, and around 5 from a shiny new DD-5.

We also made attachments detachable and attachable at ports, so now you can refit your ships to your own needs. Nevertheless, we also integrated a whole lot of new brigades: from Heavy-Artillery Secondary Armament, Reconnaissance Planes up to Smoke Launchers and Camouflage Equipment for low Visibility, you now have a broad selection range of attachments for your ships. After you research the Nuclear Propulsion tech for ships, you may as well fit them with an engine based on nuclear technology.

In the combat system you are now allowed to define a minimum engagement time. We set it to 8 hours, which turned out to be pretty good. Single units of a fleet in combat now also have a small chance to escape the battle against an overwhelming enemy before the end of the minimum combat time– their underlying counter colour will turn grey in case of success. Target selection and the overall mechanics of engagement, detection, and positioning have been tweaked and modelled to achieve outcomes which are now generally in-line with historical and realistic dimensions. Former “Second-Class Stats” like Speed, Visibility or Detection values now play an enormous role in combat itself, and are for some smaller units even more important than the big ones, like “Sea Attack” or “Sea Defence.”

The combat mechanics have been tweaked to eliminate and/or avoid the known exploits, like “fleet-beaming” or “transporter blocking.” We also did a lot in terms of balancing and, of course, we have done a lot of research and added historically correct ship attachments to each scenario for the major nations.

Visibility is now a cat-and-mouse game where each opponent is trying to maximize its own assets.

Don’t expect BBs to be able to fire 30km anymore without some form of long-range detection. Radar/scout planes now are vital to finding the enemy. It’s really a bad thing for a proud ww1 fleet to be taken out from a distance - never being able to find the ships that fire because of their advanced radar technology.

Also it is largely affected by weather conditions... So BBs now also use night cover to close in on CVs. Of course, the closer the BBs, get the higher the chance of detection... prepare to get pummelled in the clear sky at daybreak if you didn’t make it close enough. CVs get ORG and small STR damage on its attacks where the surface ships defend themselves against the fighters.
This system also makes subs behave more naturally, as they remain hidden and wait for their chance to strike... As electric subs and later have good speed and very low visibility, they can attack and hide without the outdated DDs ever knowing what hit them.

Also, as always, the combat mechanics have been totally remodelled, and defence now actually protects the host from a portion of the damage, while having superior firepower against low-defence targets does extra damage. So now even a fleet of 30DDs with their machine gun will not make a big dent in the armor of a SHBB... while the other way around... well, not a pretty sight....

Convoy Raiding with single raiders is now also very efficient; BC’s have become specialists in this task when the proper doctrines have been researched. Detection through Reconnaissance Planes (as attachment called “Spotters”) and radar or cover through smoke-launchers is now absolutely crucial to the outcome of a fight.

I hope we’ve given you some small insight into the revised naval system. Stay tuned for next week’s diary, when I will go into detail with the all-new Radar, AA and Air-Combat Systems.

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Think you've just made a lot of people even happier :D

Has the relative cost / time to get all these new brigades come down - or is it a case of hard choices to make?
 
Could you make it so that Carrier Taskforces are naturally smaller? Would really be the top of the cake for me. :)

Very good work with naval combat, but I only want to see fixes of the sizes and I am perfectly happy. :D

EDIT: I mean the stacks, of course.
 
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Good update, good job on the game. I have a question regarding the 30 DDs vs a SHBB: I'm not sure that the odds are all in favour of the battleship but it could be possible that I have miserunderstood; could you please disclose the matter further on?
 
Nice DD.
Can't wait to play with the new heavy subs (like the French Surcouf?).
 
Good update, good job on the game. I have a question regarding the 30 DDs vs a SHBB: I'm not sure that the odds are all in favour of the battleship but it could be possible that I have miserunderstood; could you please disclose the matter further on?

A second question is on the hit that a CV takes because the embarked airplanes suffer losses. You know and understand better than me that one matter is even the complete loss of the embarked airplanes and another is the loss of the carrier. In the building this is considered in fact you can build a carrier separately from the airplanes and you can add a CV without any plane to a fleet (even though that ship is essentially useless).

Could you please keep the two matters (above mentioned) separated?

Another point is the time of engagement: as far as I know naval combat could range from a sporadic encounter to very intensive and quick fight to a longer combat. How this is reflected in the minimum time of 8 hours is difficult for me to understand.

What, in my opinion is faulty in the HOI, is that a transport that fares 8 knots can easily escape from a fleet which fares 33 knots.

Last but not least the big submarines were not an invention in WWII, they were first designed (and built) by Germans in WWI in order to transport strategic goods like rares.
 
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Looking GREAT so far.

I ment to ask earlier, if there was any chance you fellows could include the ablity to convert old BB into early carriers?
 
O MYLANTA. The dd's keep getting better. I really hope that the defence changes kill the dd death star fleets one of the biggest flaws of the original was it was better to build tons of cheap outdated ships then new more advanced.
 
I'm not sure how many models the Heavy sub will have. But the I-400 class was built in 1944.

I would suggest that Type-B1 is chosen for the 1939 model instead. It was historically IJNs first heavy submarine carrying 1 float-plane spotter per sub and 20 of them were constructed between 1940 - 1943.

This page have a good summary of Japanese submarine classes:
http://www.combinedfleet.com/ss.htm

Historic trivia: The Type-B1 class was very successful. During 1942 two submarines managed to damage USS CV Saratoga and sink USS CV Wasp. The second attack sinking Wasp must be one of the luckiest torpedo salvoes launched during the war since the stray torpedoes also managed to damage a US Battleship and sink a Destroyer. 3 ships hit with one shot!


Edit: I also hope a Carrier cannot sink itself by launching fighters and having them shot down! Very nice solution for submarines allowing ships to stay hidden even when in range.
 
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I like the nerf on DD fleets, but I don't really like the 'heavy submarine' concept. Still, pretty nice overall.
I think Its a nice addition, Japan for example built no less then 33 submarines capable of launching float-plane spotters. And heavier versions of Submarines existed in most other navies too, like the French Surcouf or US Narwhal/V-Boats.
 
Good update, good job on the game. I have a question regarding the 30 DDs vs a SHBB: I'm not sure that the odds are all in favour of the battleship but it could be possible that I have miserunderstood; could you please disclose the matter further on?

Well Balesir would be the perfect one to give you a historical answer.
But i will try my luck...

First the background theory:
Armore penetration is not linear.
Either a shot has enough speed to penetrate the armor or it hasnt.
Of course there are a lot of factors playing in like distance and angle, but that is the general concept.

A late war DDs composition:
• 5 × single 5 inch/38 caliber guns guided by a Mark 37 Gun Fire Control System with Mk25 fire control radar linked by a Mark 1A Fire Control Computer stabilized by a Mk6 8,500 rpm gyro.
• 6–10 × 40 mm Bofors AA guns (early ships carried 4 × 1.1 inch/75 caliber guns),
• 7–10 × 20 mm Oerlikon cannons,
• 10 × 21 inch torpedo tubes (2×5),
• 6 × K-guns,
• 2 × depth charge racks

Now Think about a BBs armor lets say 300mm,and multiple layers to protect against topedoes.
A quick look into my armor penetration table tells me that a 200mm high velocity would have big trouble breaking through even at below 2.000m distance...
So in short No weapons that can / have practically mounted on a DD where big enough to make a dent in the armor. However their torpedoes still pose some threat.
So the BB will not escape unharmed if that is what you are looking for....
However please look at a prewar BBs armament in comparison
8 × 380 mm/L52 SK C/34 (4×2)
12 × 150 mm/L55 SK-C/28 (6×2)
16 × 105 mm/L65 SK-C/37 / SK-C/33 (8×2)
16 × 37 mm/L83 SK-C/30
12 × 20 mm/L65 MG C/30
8 × 20 mm/L65 MG C/32 (8×4)


Now... Both main and secondary weapons here could kill a DD in a few shots.
And there are at least 10 independant cannons tracing enemies(each with 2 cannons)... You do the math!

However....
All is not lost for the lucky ones:
In AOD we have implemented a critical hit chance.
So a lucky hit from the DD can cause up to 10* the normal damage...
A single hit would not become life threatening to the BB (as the normal damage would be rather low per shot), but a few of those can definetly make or break the combat.
 
Well. In reality 30 DD flotillas (90-150 destroyers) going up against a single Battleship (no matter what size) would end very badly for the Battleship very quickly.

Remember that only the main guns and engine were protected by thick armour. Normally battleships used an "All or Nothing" Layout having either full protection, or no protection.
The entire superstructure on a battleship for example were generally not more protected then that off a smaller ship. It's also possible for lucky hits and damage from fires or smoke to hit the rangefinders, knock out the radars and basically prevent any of the Battleships larger guns from shooting, making it blind.

The small guns on a Battleship had just as much protection as those on the Destroyers (In fact they were identical on many occasions).

The only other difference is Torpedoes, 90 DDs x 4 = 360 or more off them to be exact.

If someone wants to visualize you can imagine a shoal with hundreds of piranhas fighting a single shark.
 
I have two questions related to the naval matter:

- Did you do something to solve the unlimited fleet range issue for AI? It's critical for a correct simulation of the war in the Pacific and it shouldn't be that difficult to remove, is it?
- About convoy raiding, when you sink a convoy the supplies that were transported are actually lost or you still have to sink ALL the convoys of the nation in order to make them starve?
 
Well. In reality 30 DD flotillas (90-150 destroyers) going up against a single Battleship (no matter what size) would end very badly for the Battleship very quickly.
Since no battle of ~100 DDs against a BB took place, what would happen is largely conjecture, but in AoD I'm not sure I would be happy as either side. What is happening is that attackers with armament significantly "lighter" than the defender's armour inflict less damage - but not no damage. There will be danger to both sides; the DDs will assuredly take heavy losses, but the BB cannot feel 'safe'.

On top of simple armament/armour considerations, though, there are other factors in play. For one thing, BBs tend to have better radar and maybe a spotter or three - but they are also easier to see and target. DDs, meanwhile, tend to be faster. All these factors are relevant - both in real life and in AoD...

So - who would win? Depends who gets surprise/gets lucky; depends on the weather; depends on the details of the ships' designs (are we talking old, WW1 tubs or current models?). It also may well not end with all of one side sunk - running away is eminently possible in the system we have - depending on speed, weather, night time, etc., etc.
 
I ment to ask earlier, if there was any chance you fellows could include the ablity to convert old BB into early carriers?
'Fraid not. It is really not that far different from a rebuild - and those that were converted mid-build mostly (not quite all, I know, but we have to make some sacrifices) happened pre-1936. In the same vein the radical overhauls of the Italian BBs cannot be done by 'conversion', either - but again it's not so very different from a rebuild.
 
Since no battle of ~100 DDs against a BB took place, what would happen is largely conjecture, but in AoD I'm not sure I would be happy as either side. What is happening is that attackers with armament significantly "lighter" than the defender's armour inflict less damage - but not no damage. There will be danger to both sides; the DDs will assuredly take heavy losses, but the BB cannot feel 'safe'.

On top of simple armament/armour considerations, though, there are other factors in play. For one thing, BBs tend to have better radar and maybe a spotter or three - but they are also easier to see and target. DDs, meanwhile, tend to be faster. All these factors are relevant - both in real life and in AoD...

So - who would win? Depends who gets surprise/gets lucky; depends on the weather; depends on the details of the ships' designs (are we talking old, WW1 tubs or current models?). It also may well not end with all of one side sunk - running away is eminently possible in the system we have - depending on speed, weather, night time, etc., etc.

Is it possible, in terms of game mechanics, that by chance a couple of torpedoes can sink the battleship?
 
Since no battle of ~100 DDs against a BB took place, what would happen is largely conjecture
Correct, I forgot to add the word "probably" :p

~100 DDs would also represent 150,000ton or more combined. And probably cost more to make then any Single Battleship. So In a balance aspect, they probably should win too.

The advantages of Battleships start to mount as you gather a few of them together. This should be true in HoI2 & AoD aswell because off how stacking works. Then no amount of Destroyers would be happy approaching them since their combined fire can sink the DDs faster then they can close in.

Only when night or weather can conceal the DDs easier then the BBs should they be dangerous.
Really looking forward to the next DD, hope Radar will have an impact in these situations too perhaps by reducing night or weather penalties.


Edit: Another small concern, why are the 4concealed ships in the top screen shot firing but not the two German ships that are spotted? I think it would feel more natural if fire would reveal your position and the two ships not firing right now should be able to stay hidden easier instead?
 
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