Anti-Air strange behaviour

[MaB1708]

Hello all,
still ramping up with HCE I made these observations in GIUK: Gauntlet that I would like to share with you for comment, for me to better understand:
Situation is I am playing blue and when attacked by the Nanuchkas the following behaviour shows: In a direct line between the Nanuchkas and the merchants is the Boone. Nanuchka is directing some Sirens towards the Boone and some towards the merchant. Almost same bearing, some missiles aimed at merchants do directly pass over the Boone. However what happens is that Boone seems to only react (through these RIM missiles) against those Sirens that appear to be aimed at herself, while Boone constantly ignores all Sirens passing the ship towards the merchants.
In staff options, both Surface SAM rate and AAW Auto-fire are set to Heavy, Optimum resp.
This behaviour is strange, I cannot believe this is prototypical, the merchants are the HVUs in this scenario.
Is this a bug, or a design flaw in the scenario or will I see this unusual anti-air behaviour throughout HCE? Any thoughts, comments, etc welcomed as always.
Bests,
Martin

[Warhorse64]

Are the Boone and the merchant in the same group? Generally groups will not fire SAMs in defense of other groups.

[MaB1708]

Thanks, Warhorse, good point. I might understand that groups do not fire SAM to protect other groups (which I assume is far from being prototypical), but in my little Gauntlet scenario all surface units remain within the same group.
Bests,
Martin

[VictorInThePacific]

Maybe the captain of the Boone owes money to the captain of the freighter?

Seriously, though :

How exactly did the Sirens arrive? Were the ones targeted on the FF ahead or behind those targeted on the freighter? It may be that the ones in front get shot down first, especially if they are targeted on the FF. The FF has a certain rate of fire, and if it uses that up in defending itself, the missile launcher may not be available in time to defend the freighter.

I also have had problems getting my SAMs to shoot, admittedly in an earlier version of the game, so personally I would not let the Nanuchkas get within 60 nm of my freighters.

I have a solution to this scenario which I will post in a few days. Perhaps you can test it to see if it works with the current rules as well.

addition: i just noticed that mackb has posted a solution to this scenario, which i generally agree with, but i think i can add some refinements.

[mack2]

Doesn't the SAM fire rate at heavy indicate firing 2 or 3 missiles at every incoming missile? Meaning the ship might not have enough to fire at the other missiles?

[MaB1708]

Thank you both for your thoughts, IIRC neither rate of fire nor capacity were an issue here. But I will doublecheck. Maybe some comment from the dev/support corner wether we should expect units (here even in the same group) to defend other frienly units.

Bests,
Martin

[CV32]

MartinB, I ran a couple of test scenarios (using the GIUK battleset). Tony and I were in IRC channel at the time I ran the tests, to discuss the results.

In the first scenario, one warship was attached as an escort to a group containing merchants.

In the second scenario, the warship was in a group by itself, but traveling in close proximity to a group containing only merchants.

In both scenarios, the warship acted to defend both itself and nearby friendly ships from incoming missiles. Air defense settings did not affect this behavior.

So, I didn't see the problem you are reporting. Can you get a savegame and send it to hc3@harpgamer.com?

[VictorInThePacific]

Some more detailed analysis.

Martin, perhaps you can see if your situation fits with the following.

The 2 Nanuchkas have a maximum of 12 SS-N-9 Siren missiles, which have a maximum range of 60 nm, although really the practical range may be as low as 20 nm, which is the range at which the Nanuchka radar detects a "silent" surface target. (The Soviets tend to have much worse detection capacity than the NATO forces, and this can be used to good effect.) Due to this short range, the NATO forces should be able to do a number on the Nanuchkas.

The Sirens travel at 600 kn (www.warfare.ru/?lang=&catid=312&linkid=2560) = 6 s per nm.

The NATO FF Brave has 2 Sea Wolf launchers and 12 missiles.
range 3 nm, speed 1300 kn (?), hit 80%, 15 s cycle time.
It should be able to shoot down 1 missile per cycle time with guns.

The NATO FF Boone has 2 SM1 launchers and 36 missiles.
range 20 nm, speed 1300 kn (?), hit 60%, 15 s cycle time.
Its Phalanx gun should be able to shoot down 1 missile per cycle time.

Assume that all the Sirens are launched in one batch at the Brave (you can arrange this by putting the Brave in front). The Brave will have 3 x 6 = 18 s, which gives 2 shots, killing about 3 Sirens, plus one for the guns. The Boone will have maybe 15 nm (90 s) to respond, so it will get off 6 shots, killing about 7 Sirens. One should get through, which may or may not hit the Brave. A hit will sink the Brave. This calculation is inaccurate for 3 reasons: the results will typically give more or less hits than the average result, the Boone tends to fire late, and the computer tends to spread out its Siren fire.

If all the Sirens are launched in one batch at the Boone, the Brave won't get to shoot. The Boone should now respond over 20 nm (120 s), so it will get off 8 shots, killing about 10 Sirens, plus one for the gun. One should get through, which may or may not hit the Boone. A hit will sink the Boone.

If the Sirens are launched at both NATO frigates, none of them should be hit.

In none of these scenarios do the NATO ships use up all their missiles, but in some cases they ARE limited by the launcher cycle time.

What is clear from this calculation is that if one Nanuchka is sunk before it gets to launch Sirens, the other one will have no chance of hurting the NATO ships.

Now let's consider under what circumstances the freighters might get shot. Are the freighter radars OFF? They should be. Then the Nanuchkas will really need to close to 20 nm before they get to shoot, in which case the Boone gets less time to respond (the Brave won't participate in this situation). Also, the gunners on the Boone might be asleep (sorry, I mean the computer fire control system might fire late). So it could easily be possible for the Boone's standard missiles to be overloaded, and while the Boone doesn't get hit, some Sirens will hit the undefended freighters.

Summary: If all the Sirens are launched in one batch at one NATO ship, there is a good chance that that ship will be sunk. If all the Sirens are launched in one batch at any combination of NATO ships except the Brave, there is a good chance that at least one ship will be sunk. If all the Sirens are launched in one batch at the Brave (good point defense) plus one other NATO ship, it is unlikely that any ship will be sunk. If half the Sirens don't get launched, it is unlikely that any ship will be sunk.

THEREFORE you should sink at least one Nanuchka before it gets to fire, which can pretty much be guaranteed. Alternatively, you can use the superior NATO detection to just avoid the Nanuchkas and sneak into Narvik.

[NefariousKoel]

I'd think that the Boone, being a Perry class frigate and having a single rail one-armed bandit, is being restricted by it's ROF.  Especially since the Sirens are small targets flying at Low (or is it VLOW for SS-N-9? Can't remember - think they're seaskimmers) meaning they won't be detected and targetable until they're extremely close to the Boone. While OHPs have some "area defense", it's not very good and certainly not very capable at volume fire.

A mixture of being detected at very close range and the rate of fire for the single SM1 launcher on Boone is the culprit, methinks.

[VictorInThePacific]

One more thing.

Martin, it occurs to me that you might be experiencing a phenomenon similar to what I discuss in my thread "naval SAMs don't shoot", where the area defense (Boone) does not start shooting at maximum range and as a consequence gets overwhelmed.

[NefariousKoel]

Also keep in mind that the launching vessel needs to have the target detected by it's own sensors for those SAMs.  If the fire control directors for those radar-guided SAMs can't see the targets that your AWACS is telling you are there, it can't shoot at it. [;)]

For instance, the radar horizon from a small ship to a small sea-skimming missile is something like 4-8nm. Though your SM1s can reach out to 20nm, it can't until the target is being painted by your radar.

[Warhorse64]

Actually, per the H4 paper rules, the radar horizon from a small ship's mast height to a target at VLow altitude is 22nm. The SPS-55 radar on an OH Perry frigate would start rolling to see an SS-N-9 missile at 16nm. The SPS-49 would start rolling at 15nm due to a restricted ability to look that low.

[VictorInThePacific]

Also keep in mind that the launching vessel needs to have the target detected by it's own sensors for those SAMs. If the fire control directors for those radar-guided SAMs can't see the targets that your AWACS is telling you are there, it can't shoot at it.

Thanks, Nefarious, for clarifying that. I wasn't sure if that was required.

[FransKoenz]

Really exiting topic. People take time to compare game with reality.
Carry on![;)]
 
Greetings,
Taitennek
 

[NefariousKoel]

ORIGINAL: Warhorse64

Actually, per the H4 paper rules, the radar horizon from a small ship's mast height to a target at VLow altitude is 22nm. The SPS-55 radar on an OH Perry frigate would start rolling to see an SS-N-9 missile at 16nm. The SPS-49 would start rolling at 15nm due to a restricted ability to look that low.

Ahhh yes. You are right. If that first detection is missed, it would be very close indeed.

And your welcome, Victor. There's a lot to learn from Harpoon. I've tinkered with it for a couple decades in various forms and it's taught me a lot. Very fulfilling. [8D]

[MaB1708]

All,
I have no savegame available for what occured in my game. If I am able to reproduce it I will be happy to send it over.
BUT:
Many thanks to the comments and replies here in this threat, as it is said above, there is so much to learn and all your posts helped me a lot in better understanding the sim.
So my "issue" might be bug or feature, but this thread for me was definetely worth it, as so many advanced simmers enlarged my knowledge of game mechanics.
Cheers,
M