Air Attack/Defense in naval battles

[bip]

How does this work in MtG? So my fleet has a combined Anti-Air value (displayed in the naval battle screen). How does it affect the attacking enemy planes and the damage they deal to my ships in a naval battle? Can anyone give a good explanation, especially since the wiki is incomplete and seems to be outdated on this.

 

[sekelsenmat]

The ship being attacked can kill attacking planes. The rest of the fleet AA value decreases the damage done by the attacking planes, it "suppresses" them.

Read all the stuff here:

Naval battle - Hearts of Iron 4 Wiki

hoi4.paradoxwikis.com

and here:

Is naval AA worth it or not, trying to do some math?

I think this is an interesting question. Naval AA do two this, shoot down Aircrafts and reduce damage Aircrafts deal on your ship. According to the wiki, only the ship attacked will have a chance to shoot against the Aircrafts (so AA cruisers is...

forum.paradoxplaza.com

especially since the wiki is incomplete and seems to be outdated on this.

I think it isn't outdated.

 

[Riekopo]

Basically it works in a really dumb way that makes Ship AA totally weak and underpowered and pointless to build AA Cruisers like in real life. Only the exact ship being attacked can shoot down enemy planes.

 

[ecpgieicg]

Basically it works in a really dumb way that makes Ship AA totally weak and underpowered and pointless to build AA Cruisers like in real life. Only the exact ship being attacked can shoot down enemy planes.

Well, area AA was never a thing in WWII. It wasn't a thing until basically now and still isn't for many countries. Not convinced? Ask the Sheffield that is in the bottom of Atlantic how effective it found its AA suite was.

Escorts with good AA can block avenue of approach and in general serve as a magnet for attack. The latter is the case in HOI4 and you can say the former is reflected because the latter is.

 

[ecpgieicg]

Basically it works in a really dumb way that makes Ship AA totally weak and underpowered and pointless to build AA Cruisers like in real life. Only the exact ship being attacked can shoot down enemy planes.

Ofc, I see that you disagree. But on what basis do you think otherwise? What is the historical evidence that escort AA was able to provide area AA coverage?
Opinions are worthless without facts.

 

[bip]

Thank you for the replies. The wiki page says that it was last verified for 1.8, that's why I thought that it was outdated. So, do I understand it correctly that there are basically two steps for an attack by planes in a naval battle:
1. planes select a ship to attack and that ships AA value determines how many planes get shot down,
2. planes attack the ship and the damage dealt is calculated based on that individual ship's AA value as well as the whole fleet's AA value ?

Does step 2. mean that I can still significantly reduce the damage done to my ships by planes by putting a lot of dedicated AA ships into the fleet?

Another question: if I have a carrier in my fleet how will the planes from that carrier affect enemy planes attacking my ships in the naval battle?

 

[ecpgieicg]

Thank you for the replies. The wiki page says that it was last verified for 1.8, that's why I thought that it was outdated.

The core mechanics hasn't changed. The version tag is more of an advisory warning. It takes manual verification to update the tag. So you see it can take a long time before the tag is updated even if the information is up to date.

2. planes attack the ship and the damage dealt is calculated based on that individual ship's AA value as well as the whole fleet's AA value ?

Yes

Does step 2. mean that I can still significantly reduce the damage done to my ships by planes by putting a lot of dedicated AA ships into the fleet?

Yes, in theory. But why would you have dedicated AA ships (implying that they can't do other things)? Don't AA sit on separate slots and cost minimal amount of IC?
The real corollary is new ships with good AA can somewhat protect old ships without AA in the same engagement.

Another question: if I have a carrier in my fleet how will the planes from that carrier affect enemy planes attacking my ships in the naval battle?

(I see the question. Don't know the answer.)

 

[Axe99]

Well, area AA was never a thing in WWII. It wasn't a thing until basically now and still isn't for many countries. Not convinced? Ask the Sheffield that is in the bottom of Atlantic how effective it found its AA suite was.

Escorts with good AA can block avenue of approach and in general serve as a magnet for attack. The latter is the case in HOI4 and you can say the former is reflected because the latter is.

Ofc, I see that you disagree. But on what basis do you think otherwise? What is the historical evidence that escort AA was able to provide area AA coverage?
Opinions are worthless without facts.

Actually, even prior to WW2 the RN had a doctrine of its destroyers using their main armament to provide "umbrella" AA fire over the capital ships. Can't recall off the top of my head what the USN or Japan did, but supporting AA Fire was absolutely a big thing in WW2, from the start, and it only developed further with radar. The best book I'm aware of is Norman Friedman's Naval Anti-aircraft Guns and Gunnery - I highly recommend it to anyone interested in the issue. If you think I'm blowing smoke, let me know and I'll ferret through and dig out some quotes and similar.

Another question: if I have a carrier in my fleet how will the planes from that carrier affect enemy planes attacking my ships in the naval battle?

Quite differently to in a normal air battle. In the defines, you'll see that carrier aircraft have much greater capacity to disrupt incoming aircraft in a naval battle (that those carrier aircraft start in, on carriers). I'm in the middle of doing some tests to both look at exactly how it works (at the moment, the degree to which carriers disrupt seems to make smaller carrier forces easily overwhelmed by large ones, in a way that at least wasn't near as reliable as looks to be happening in the tests), but there are definite benefits to carrier aircraft vs land-based aircraft. Carrier bombers (in the actual battle) also get bonuses to naval strike.

 

[ecpgieicg]

Actually, even prior to WW2 the RN had a doctrine of its destroyers using their main armament to provide "umbrella" AA fire over the capital ships. Can't recall off the top of my head what the USN or Japan did, but supporting AA Fire was absolutely a big thing in WW2, from the start, and it only developed further with radar. The best book I'm aware of is Norman Friedman's Naval Anti-aircraft Guns and Gunnery - I highly recommend it to anyone interested in the issue. If you think I'm blowing smoke, let me know and I'll ferret through and dig out some quotes and similar.

I am aware of the theories in RN and USN (not IJN) in the interwar period that discusses how to best do AA coverage and support. Yes they would try to position in such a way that AA coverage of individual ships support each other and dead zones covered by one another. It does not mean they succeeded in doing it. All that doctrinal preparation has nothing to do with whether in reality the AA fire of one ship can deter attack on a different ship.

Tell the dive bomber attacking your battleship or carrier several thousand yards down south that they should care about your 20mm AA fire.
Do you have actual sources that point to AA kills on planes attacking friendly ships? Not doctrine. Not intention. Reality.

 

[Axe99]

I am aware of the theories in RN and USN (not IJN) in the interwar period that discusses how to best do AA coverage and support. Yes they would try to position in such a way that AA coverage of individual ships support each other and dead zones covered by one another. It does not mean they succeeded in doing it. All that doctrinal preparation has nothing to do with whether in reality the AA fire of one ship can deter attack on a different ship.

Tell the dive bomber attacking your battleship or carrier several thousand yards down south that they should care about your 20mm AA fire.
Do you have actual sources that point to AA kills on planes attacking friendly ships? Not doctrine. Not intention. Reality.

Absolutely - in terms of the AA used for support though, it wasn't the 20mm or 40mm, but the large-calibre AA - the British doctrine was to have 40 degree (iirc, about that, I can look up - and it got higher later in the war) elevation on their main guns precisely so they could provide supporting AA fire above the capital ships of the fleet. There are some great photos from Operation Pedestal showing this in action. Many British ships were also fitted with barrage fire directors - the point of which was to provide a wall of heavy AA fire at a fixed point on the perimeter of the fleet (so it was an area-based approach) that enemy bombers had to fly through. The effective range of the 4in, 4.7in, 5in and 5.25in AA guns was measured in kilometres, and was well long enough to provide supporting AA fire. 40mm Bofors could provide some supporting fire to ships close by (2pdr AA less so, but still a bit), and 20mm's and lower effective range was so small that it was really only for own-ship defence).

Indeed, some nations (Brits and Japanese) designed their cruiser-calibre guns (and the Japanese, their BB-calibre guns!) to provide AA fire support that was applicable at the fleet level.

If you read the account of the attack on Prince of Wales and Repulse in British Battleships of World War Two, you'll see clear reference to the large-calibre AA being used by both ships on attacks on either (so PoW fired on aircraft attacking Repulse, and vice versa), and it's all through accounts of Operation Pedestal. I don't have time to look up now (off to work), but if you still don't believe me (and don't feel like reading the Reports of Proceedings or similar yourself to get up to speed), reply again and I'll swing by this evening and take some photos from the books mentioned above and post in here

 

[Secret Master]

and the Japanese, their BB-calibre guns!

The Yamato famously fired bee-hive rounds from her main batteries when she was attacked during Ten-Go.

Yamato's AA fire was also famously bad during that engagement, thanks to a lack of RADAR and US planes running in waves and patterns designed to confuse or neutralize AA defense.

 

[ecpgieicg]

Absolutely - in terms of the AA used for support though, it wasn't the 20mm or 40mm, but the large-calibre AA - the British doctrine was to have 40 degree (iirc, about that, I can look up - and it got higher later in the war) elevation on their main guns precisely so they could provide supporting AA fire above the capital ships of the fleet. There are some great photos from Operation Pedestal showing this in action. Many British ships were also fitted with barrage fire directors - the point of which was to provide a wall of heavy AA fire at a fixed point on the perimeter of the fleet (so it was an area-based approach) that enemy bombers had to fly through. The effective range of the 4in, 4.7in, 5in and 5.25in AA guns was measured in kilometres, and was well long enough to provide supporting AA fire. 40mm Bofors could provide some supporting fire to ships close by (2pdr AA less so, but still a bit), and 20mm's and lower effective range was so small that it was really only for own-ship defence).

Indeed, some nations (Brits and Japanese) designed their cruiser-calibre guns (and the Japanese, their BB-calibre guns!) to provide AA fire support that was applicable at the fleet level.

If you read the account of the attack on Prince of Wales and Repulse in British Battleships of World War Two, you'll see clear reference to the large-calibre AA being used by both ships on attacks on either (so PoW fired on aircraft attacking Repulse, and vice versa), and it's all through accounts of Operation Pedestal. I don't have time to look up now (off to work), but if you still don't believe me (and don't feel like reading the Reports of Proceedings or similar yourself to get up to speed), reply again and I'll swing by this evening and take some photos from the books mentioned above and post in here

I believe you. If you don't find it too consuming, I'd love to see the passages nonetheless. It's always nice to learn and have a good read.

 

[sekelsenmat]

Basically it works in a really dumb way that makes Ship AA totally weak and underpowered and pointless to build AA Cruisers like in real life. Only the exact ship being attacked can shoot down enemy planes.

I bet the captain of the Prince of Wales was also saying this: Real life is totally dumb, I have state-of-the-art AA:

16 × 133mm DP guns and 32x 40mm AA guns! Why I only shot down 4 planes? Who wrote this real life?

And the planes sank a battleship and a battlecruiser, despite being escorted by 4 destroyers??? Naval Bombers are totally OP!!!

Sinking of Prince of Wales and Repulse - Wikipedia

en.wikipedia.org

AA was pretty crappy before proximity fuzes (for the allies) or radar controlled large guns for the Axis, and after that it was still only modestly successful. The USA shoot down numbers have to take into consideration that shooting down Kamizakis is much easier since their are coming straight to you all the way in.

This doesn't mean that the game is perfect: In the game I wonder why convoys are so good at shooting down planes, anyone know the define which sets their AA power? In reality convoys did have a lot of AA, but it should scale with tech: With early AA, even if they had a lot, it should still be crappy. With higher tech AA it should be like it is now.

Another problem is that the ship has a +/-75% chance of hitting zero planes, which increases as the game goes on (since plane agility goes up) and it doesn't scale with the Nr of planes attacking. It is obviously easier to hit something if more planes attack. There is a modelling error here. They should roll a small chance to hit each separate plane.

 

[sekelsenmat]

I am aware of the theories in RN and USN (not IJN) in the interwar period that discusses how to best do AA coverage and support. Yes they would try to position in such a way that AA coverage of individual ships support each other and dead zones covered by one another. It does not mean they succeeded in doing it. All that doctrinal preparation has nothing to do with whether in reality the AA fire of one ship can deter attack on a different ship.

Tell the dive bomber attacking your battleship or carrier several thousand yards down south that they should care about your 20mm AA fire.
Do you have actual sources that point to AA kills on planes attacking friendly ships? Not doctrine. Not intention. Reality.

Book "Six Victories", page 40: "At 5th Nov 12:30 ... 8 Blenheim (British heavy fighters) attacked at mast height the steamers Anna Zippitelli & Ascianghi ..... sinking Anna Zippitelli. The torpedo boat Calliope shot down two Blenheim"

So Heavy Fighters bombed convoys and a torpedo boat shot down two of them, because it was their escort and was next to them. Hvy Fighters should be allowed the Naval strike missiong by the way.

On the other hand it is probably hard for the game to decide which ship is next to which one and can give cover....

 

[Riekopo]

Ofc, I see that you disagree. But on what basis do you think otherwise? What is the historical evidence that escort AA was able to provide area AA coverage?
Opinions are worthless without facts.

What? LOL. You think aircraft had a magical force field that prevented them from being attacked by any ships other than the one they were directly attacking? lol....

 

[Axe99]

I believe you. If you don't find it too consuming, I'd love to see the passages nonetheless. It's always nice to learn and have a good read.

No worries - I'm a bit buggered, so here are a couple of quick paras (Prince of Wales and Repulse easy, as I only read the book in question a little while ago, but Pedestal was ages ago, so you'll have to settle for PQ18 here). In spoilers to keep the post smaller for everyone else . Naval AA in the period is actually super-interesting (and very deep) - I first read Friedman's book on Kindle, and then got a hardcopy version as I wanted to be able to "flick through".

Spoiler

16 × 133mm DP guns and 32x 40mm AA guns! Why I only shot down 4 planes? Who wrote this real life?

Naval AA gunfire during the period is actually a really interesting and deep topic, and a lot more complicated than "AA was rubbish" (even Prince of Wales and Repulse was more complicated than that, and while their sinking is popularly seen as the clear sign of 'the obsolescence of the battleship', a more nuanced reading of the events of WW2 suggests otherwise (although it does suggest that surface ships should steer clear of heavy concentrations of enemy aircraft if they don't have their own fighter defences - something the British knew well already from Crete*). It's worth keeping in mind that Germany developed the FX-1400 radio-guide bomb and the Hs-293 specifically so aircraft could attack ships outside of AA gunnery range - I've read (but I'm afraid there's no way I can remember where from, maybe Friedman?) comments from the German side to the effect that the build-up of close-in AA on ships was making dive-bombing less and less feasible over time (it's also worth keeping in mind that we only read about the successful air attack sorties, but for every air attack where aircraft hit something, there were oodles (I've got no idea of exactly how many, or even where to start with the stats) where they were just shot at, maybe lost a plane or two, and achieved nothing).

* On this, HMAS Yarra's commanding officer, CDR Hastings Harrington, considered that the German air attacks in the Med were actually better than the air attacks he faced while serving in South-East Asia around Singapore, although he may have faced IJAAF rather than IJNAF flyers. But the point being that the kind of attention Prince of Wales and Repulse got was not a surprise, nor the kind of thing the RN hadn't already dealt with before more successfully, by any stretch.

 

[Meglok]

@Axe99 gentle reminder, proximity fuses. The anti-aircraft theory in the pre-war and early war using escorts in box formations to protect capital ships was there, they just lacked the tools to make it really effective. The development of proximity fuses and radar guidance made ship AA truly deadly, esp as the doctrine was implemented and defined by the USN from 1943 on.

 

[sekelsenmat]

comments from the German side to the effect that the build-up of close-in AA on ships was making dive-bombing less and less feasible over time

Maybe the brits were already using proximity fuzes?

(it's also worth keeping in mind that we only read about the successful air attack sorties, but for every air attack where aircraft hit something, there were oodles (I've got no idea of exactly how many, or even where to start with the stats) where they were just shot at, maybe lost a plane or two, and achieved nothing).

The book "Six Victories" has nearly every british and italian/german anti-ship air attack between November 41 and March 42 in the mediterranean. Yes, there were plenty of flops in the attacks, where only planes got shot down, or even noone was hurt on both sides. Maybe there are other books for other theaters.

 

[Axe99]

@Axe99 gentle reminder, proximity fuses. The anti-aircraft theory in the pre-war and early war using escorts in box formations to protect capital ships was there, they just lacked the tools to make it really effective. The development of proximity fuses and radar guidance made ship AA truly deadly, esp as the doctrine was implemented and defined by the USN from 1943 on.

Absolutely - this started as a general point noting that other ships did support each other with AA (which predates proximity fuses by many years). However, while proximity fuses were huge (not for you as I know you're well aware of this, but for others reading, one of the big challenges of AA fire control was setting the time fuse for the shell to explode - even with a radar-supported tachymetric system, there were still errors, and not every AA system had automatic fuse-setting (so the delay between getting the fuse setting, and setting it on the shell, added further error to an equation that was trying to hit a target moving at perhaps 300kph from a platform pitching and rolling moving (and possibly turning) at maybe 40-60km an hour - the proximity fuse did away with all of this, making things significantly easier) that was reasonably accurate, the time it took to set the fuse slowed , but the German concerns with British AA predated their use of proximity fuses (which were very limited in the European Theatre) - proximity fuses had a huge impact on the number of "rounds per bird" (RPB) it took to shoot down an enemy aircraft, but even before their introduction, large-calibe AA fire could be dangerous - I've included a table of US AA results from the September 2014 edition of Warship International below - note that in 1944 and 1945, more aircraft were shot down by 40mm fire (which didn't have proximity fuses) than 5" (VT (proximity fuses for those new to it) and common (time fused)) combined, and that the while proximity fused shells were more than about twice as good as time-fused shells, the time fused shells continued to account for plenty of aircraft shot down.

US Ammunition Performance by year (Warship International 51/3, Sep 2014, p. 248)
	5" Comp.	5" VT	40mm	20mm
Total for 1942
Rounds	15110​		5576​	155603​
Kills	60​		2​	86​
RPB	252​		2788​	1809​
Total for 1943
Rounds	27242​	9128​	114889​	697955​
Kills	46​	61​	81​	116​
RPB	508​	155​	1320​	6017​
Total for 1944
Rounds	72902​	32826​	432680​	1103028​
Kills	63​	78​	183​	118​
RPB	1157​	421​	2364​	9308​
Total for 1945 to August 14
Rounds	108516​	75961​	718699​	1308370​
Kills	173​	207.5​	476.5​	297.5​
RPB	627​	366​	1508​	4398​

Maybe the brits were already using proximity fuzes?

Not the radar-based one - they did use some (iirc - I'm going from memory) with photoelectric proximity fuses on rockets, but these were not as effective.

The book "Six Victories" has nearly every british and italian/german anti-ship air attack between November 41 and March 42 in the mediterranean. Yes, there were plenty of flops in the attacks, where only planes got shot down, or even noone was hurt on both sides. Maybe there are other books for other theaters.

Thanks for your thoughts O'Hara is very good (although I haven't read this one - but I'm sure it's tops - he's written more about the Med than anywhere else, so I can't see him fluffing it), but there will still be plenty of gaps (there just aren't enough pages in the book to cover all the attacks to the level of detail required to know what happened ) but generally speaking even going down to Reports of Proceedings isn't enough to get all of the attacks and detail. I would expect any robust study would require the records of the air units attacking as well, which for every attack on every ship is a lot of records (and for Japan, I imagine many will have been destroyed) in a few different languages. I am keeping a record of the attacks I do read about though, but it'll take years of reading to have any idea whether that will be indicative (it'll be great for a record of damaged and sunk ships, but getting the total attacks by number of aircraft (by type) targeting each ship, and the outcome (including for the aircraft), is the tricky bit).

Either way, O'Hara's books review very well. If you ever read Struggle for the Middle Sea, don't pay too much attention to the strategic stuff (he's off by a mile), but his accounts of individual accounts are top-drawer

 

[sekelsenmat]

I've included a table of US AA results from the September 2014 edition of Warship International below - note that in 1944 and 1945, more aircraft were shot down by 40mm fire (which didn't have proximity fuses) than 5" (VT (proximity fuses for those new to it) and common (time fused)) combined, and that the while proximity fused shells were more than about twice as good as time-fused shells, the time fused shells continued to account for plenty of aircraft shot down.

Ok, your data seems to prove that proximity fuzes were not such the game changer for naval AA that I thought they were. Going from 20mm to a good Bofors 40mm was as larger improvement it seems.

Maybe in game terms, the 1940 AA could be Bofors (or equivalent) 40mm and the last tier AA (43 or 44? don't remember) would be proximity fuzes.

I think it would have made a bigger difference for the germans who were targeting Heavy Bombers. For ships level bombing is not a big threat and the rest (torpedo bomber, dive bomber, mast-height attack) can be countered with light AA. Although radar range finding was effective enough to bring down heavy bombers. Somewhere I read that the japanese developed a good computer fire-control and shot down some B-29s (or other model) with it, but the americans just learned to go around this particular strongpoint. Can't find the link to that now, however.

Thanks for your thoughts O'Hara is very good (although I haven't read this one - but I'm sure it's tops - he's written more about the Med than anywhere else, so I can't see him fluffing it), but there will still be plenty of gaps (there just aren't enough pages in the book to cover all the attacks to the level of detail required to know what happened ) but generally speaking even going down to Reports of Proceedings isn't enough to get all of the attacks and detail...

All true. I am also doing something like this, although much, much more modest. Just wanted to roughly get statistics of the chance of a naval attack or sub attack to sink a convoy, and of a plane being shot down. And I was planning to just use the info from that book. It takes already plenty of time like that.

Here is what I have so far:

Date​	Convoy​	Recon (U=Ultra, R=air recon)​	Destination​	Attacker​	Result​
25 Oct​	2 ships 1 DD Strale​	U​	Benghazi back to Brindisi​	Force K 2 CL+2DD (?)​	K sortie found nothing​
31 Oct​	2 ships 1 TB​	U+R​	Benghazi​	4 Wellington TAC​	hit nothing​
1 Nov​	2 ships 1 TB Procione​	U​	Benghazi​	Force K 2 CL+2DD (?)​	K sortie found nothing​
3 Nov​	2 ships, 1 TB Calliope​	R​	Africa->Benghazi​	8 Blenheim Hvy F + 1 Wellington​	1 convoy sunk, 2 Hvy F shot down​
7 Nov​	2 ships, 1 TB Pegasus​	U+R​	Benghazi​	Wellington+Swordfish​	found nothing​
​	​	same convoy​	​	12 Blenheim Hvy F​	1 sunk, 3 shot down​
9 Nov, Beta Convoy​	​	​	​	Force K​	https://en.wikipedia.org/wiki/Battle_of_the_Duisburg_Convoy​
Page 53​	​	​	​	​	​
11 Nov, 2 ships​	​	​	Trapani -> Tripoli​	​	no action​
14 Nov, 2 fast motorships Citta 19kts, 2 DD​	​	U​	Benghazi​	​	no action​
14 Nov, 2 ships​	​	R Cant Z506​	Gibraltar->Malta​	1 S.79, 2S.84​	both sunk​
Lots of East Mediterranean allied convoys, no attacks, 10 DD shipping stuff from Cyprus​	​	​	​	​	​
Page 58​	​	​	​	​	​
15 Nov, 2 ships, 1 TB​	​	U​	Benghazi​	6 Blenheim Hvy F​	mast height, damaged both, aborted convoy​
20 Nov, 2 fast citta 19kts, 2 DD​	​	U​	Benghazi​	6 Blenheim Hvy F​	3 shot down​