Submarine Warfare

[PoorOldSpike]

I'm by no means a sub expert so I'm running a series of tests to educate myself and might as well post the results in this thread for good measure, they're all pure vanilla 7.1.8, clear weather.
Feel free to comment and also correct me if I've overlooked anything
The sub is a US Balao class which was the most numerous US type in the Pacific.

SUB MOVEMENT
The surfaced sub can move 3 hexes



But it can only move 2 hexes when submerged (below). You can stretch it to 3 hexes if you like but the icons around the perimeter warn you it'll surface at the end of its move-

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SPOTTING
The surfaced sub moves along the blue arrow and spots a Jap destroyer (Akizuki 1943) at 4 hexes.
The destroyer can't see the sub even though it's on the surface.



If the sub was submerged (below), the spotting range drops to only 2 hexes (periscope range) limiting the subs spotting range.



The sub continues moving on the surface to within 3 hexes of the destroyer, but although the ship is pinging, it still hasn't detected the sub-

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DESTROYER SPOTS SUB
I move the surfaced sub to within 2 hexes of the destroyer and the sub spots it at last with a combination of pings and eyeballs, and opens up with its guns. (For the record the guns inflicted 5 damage per turn on the sub in this and subsequent tests)




In this next test I submerged the sub and moved it to within 2 hexes of the destroyer and the destroyer detected it by pings and began firing "hedgehog" type projectile depth charges at it.
(Sometimes hogs inflicted 5 damage per turn, and sometimes 3 damage, so obviously they're not as effective as guns, therefore attacking while submerged will possibly reduce damage to the sub)

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SUBMARINE ON THE ATTACK
In the previous tests I held the subs fire, but now it's payback time..
Below: I move the surfaced sub into torpedo attack range (2 hexes) and launch a torpedo attack, but the destroyer wasn't even scratched (note the very poor combat odds) because destroyers were historically much harder to hit than fat juicy tankers and supply ships etc.




In the test below I move the sub into a deck gun attack range (1 hex) with the surfaced sub but the combat odds are appallingly bad, the japs must be rofling like crazy. In both this and the previous sub attack, the sub cannot move after firing its gun and torpedoes, so it just has to sit there as the jap throws everything at it during the jap turn..

[PoorOldSpike]

SUB TORPEDO HITTING POWER, 2 hexes range

In the editor I placed a submerged US Balao sub at the centre of a ring of Jap ships. Its periscope range is 2 hexes so they're all visible, but they can't see him because the destroyer hasn't started pinging yet, and the sub hasn't given away its position by launching any torpedoes yet.
This first eye candy screenshot is just to let us admire the jap types graphics while munching our popcorn-





Below: this screenshot shows what the projected 2-hex range torpedo combat results would be (but of course with the 'Combat randomizing' option setting 'on', the actual results may vary slightly)
Note the destroyer is the toughest to hurt, while the others could take varying degrees of damage up to 2+.
So generally speaking a single sub doesn't have the punch to sink any ship in one turn (unless the ship is already badly beat up), so the best it can hope for against a healthy ship is to inflict some damage then evade the destroyers and hopefully make further attacks (but its torpedoes take several turns to reload, so it could surface and use its deck gun instead if the tactical situation allows it) to keep whittling down the targets strength, (and several subs operating as a "wolfpack" would of course inflict much more damage)-


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SUB TORPEDO HITTING POWER, 1 hex range
Torpedoes usually do more damage at this range, (the submerged US Balao sub is in the centre of this composite screenshot, but of course I moved it around to take 1 hex readouts)-

[PoorOldSpike]

SUB DECK GUN HITTING POWER
The surfaced US Balao's gun versus jap shipping is not quite as powerful as torpedoes, but it can fire every turn, whereas torpedoes take several turns to reload-

[GabeKnight]

Note that torpedo damage is higher the closer you are to the target.

[PoorOldSpike]

Note that torpedo damage is higher the closer you are to the target.

Thanks mate, I've just edited a screenshot of 1-hex range combat readouts into my earlier post.

[LNDavoust]

Note that torpedo damage is higher the closer you are to the target.

Yep, I also noticed that. What I am no so sure about is if there is any difference between shoot befor (not) moving or moving and then shoot.

[bru888]

Based on this SUB TORPEDO HITTING POWER data, I'm starting to feel better about vanilla subs (sorry Gabe). I know, IRL, that a single torpedo could sink any ship in WW2 but in OOB, I have a feeling that this may in fact be not reproducible without throwing naval warfare way out of balance in this game. Anyway, how many single-shot torpedo kills were there IRL? I would think three or more torpedo hits would be needed to sink a carrier, battleship, or cruiser whereas a couple may be enough for a transport, supply, or merchant ship. By the way, Spike, these are on 0 experience for the sub? I wonder what happens to the battle result odds when considerable experience is added or a commander is assigned.

[Horst]

This is not about instant-killing everything with subs or generally with torpedoes, but at least inflict something like 1 damage instead of 0 or 0+ every 3-4 turns or what vanilla usually does with subs versus combat ships.
I know that subs were historically mainly used against slow, unarmored merchant ships but only few (official) scenarios offer that.

Torpedo damage, like default ranged naval-attacks, versus naval targets is susceptible to target-distance and -movement. Own movement, or rather the change in distance to the target, doesn’t deteriorate for the torpedo damage unlike the surface ranged attacks.
After my complain about instant-sinking freshly embarked land-units, it looks like it was changed that all naval units enjoy their maximum-move defense on the first scenario turn or after units embark to a degree but not sure due lack of AI embarking possibility.
On their next turn, they are more vulnerable again if naval units don’t move, but luckily no instant-sinking anymore.
So keep in mind when testing naval/torpedo damage output in the game, and less theorizing in game files, that the first turn gives the maximum-move defense while from second turn on the idle/no-move defense. And also remind yourself that there is a cooldown for torp attacks, so these should do somewhat more damage than any other default attacks that are available every turn.

I’ve been playing with similar sub/torpedo attack values and cooldowns like in the GabeMod for a while and had no real annoyance with that. I guess it all depends what you are used to or expect from the game and/or reality/history.
I’m rather annoyed by the terrible battery-recharging rule for subs. I’d rather like to fully recharge in a single turn surfaced, so especially AI subs won’t stutter constantly in surface-mode anymore and become easy prey. The AI always tries to destroy something nearby with most AI tasks, therefore you won’t see much patience with this battery-recharge rule either. It’s the same silliness like AI air and land units returning with 1 strength back to the front lines.

[PoorOldSpike]

..By the way, Spike, these are on 0 experience for the sub? I wonder what happens to the battle result odds when considerable experience is added or a commander is assigned.

Yes all the tests are with experience '0' for subs and ships, vanilla OOB, no mods or tweaks,no commander, v. 7.1.8.
You raise an interesting point about experience so I just ran this test below with a maximum-exp 5-star Balao submerged sub (circled) against '0' exp ships at 1-hex torpedo range. (I moved him around and took 1-hex range composite screenshots)
The results show that 5-experience gives the torpedoes greater hitting power against only 3 ships (Cruiser, Supply ship and Merchant ship), Conclusion- Experience does inflict greater damage, but only against the 3 ships mentioned.
(Of course, exp might also affect other abstract things 'behind the scenes' like the subs spotting range and improved resistance to torpedo attack etc)
PS- how do I assign a hotshot commander to the sub to see if he has an effect?

SUB EXPERIENCE '5-star' TESTS, torpedoes at 1-hex range

[Erik2]

You assign commanders in the editor using the 'Unlock Commander' effect.

commander.jpg (51.7 KiB) Viewed 4654 times

[PoorOldSpike]

You assign commanders in the editor using the 'Unlock Commander' effect.

Thanks, I just put him in command of the sub, and also gave him 5-star experience for good measure, but he had absolutely no effect on the combat results, have I done something wrong? (sniffle)
Below: His stationary submerged Balao sub is in the middle and I order it to make torpedo attacks on the surrounding ships, but the projected combat readouts are exactly the same, regardless of whether he's aboard or not (I ran further tests to double-check and confirm it)

[PoorOldSpike]

..What I am no so sure about is if there is any difference between shoot befor (not) moving or moving and then shoot.

Not sure I understand what you mean mate. Torp range is 2 hexes so the sub has no choice but to move to get within range to fire.
PS- these ongoing sub tests are the most difficult tests I've ever done because there are so many variables and factors to be taken into account, but eventually I hope to be able to condense everything into one post called something like 'Summary of Sub tactics'..

[PoorOldSpike]

THE 'TORPEDO IMPROVEMENTS' SPECIALISATION
(US 'Balao'-class sub, static, submerged, 1 hex range, v.7.1.8 )

This first pic is without the Specialisation-





And this second pic is with the Specialisation, notice how the hitting power has increased against all the ships except the destroyer-



Summary- so, based on this test and earlier tests, the best way to get maximum torpedo hitting power is-
1- Use the 'Torpedo Improvements' Spec.
2- Fire at 1 hex range

Note: Giving a sub any Experience level has no effect on combat
Also, assigning a Commander has no effect either.

[Mojko]

Thanks, I just put him in command of the sub, and also gave him 5-star experience for good measure, but he had absolutely no effect on the combat results, have I done something wrong? (sniffle)
Below: His stationary submerged Balao sub is in the middle and I order it to make torpedo attacks on the surrounding ships, but the projected combat readouts are exactly the same, regardless of whether he's aboard or not (I ran further tests to double-check and confirm it)

Your commander has no effect on the torpedo attack value which is the actual attribute which is used in this combat calculation (as opposed to naval attack (small or large)). Also, note that the target is using torpedo defense attribute (as opposed to naval defense (small or large)). You can easily check the torpedo attack and torpedo defense stats in the Unit Navigator.

Submarine uses naval attack attributes only when attacking with a deck surface gun.

[PoorOldSpike]

..note that the target is using torpedo defense attribute (as opposed to naval defense (small or large)...

Sorry, what does that mean? I didn't give the enemy AI ships any attributes at all.

[bru888]

I think Mojko is pointing out that what we are seeing here, with your subs submerged, is torpedo attack versus torpedo defense rather than naval (surface) attack and defense. Also, he mentions that commanders have no effect on torpedo attack values, which is revealing and probably could be considered a game flaw due to it having been overlooked. That is, there should be some provision for having a few commanders who lend value to submarines and apparently there are none.

Indeed, if you look through commanders.txt, there are plenty of references to "naval_attack" and "naval_defense" but not "torpedo_attack" or "torpedo_defense." So, here's an assignment if you choose to accept it, Spike. :

Save your original commanders.txt file someplace. Next, choose a naval commander with "weapon" naval attack ratings and substitute the word "torpedo" for "naval." Disregard the "small_" and "large_" attack factors (there are no corresponding torpedo values in units.csv) and just go with "weapon = torpedo_attack, 2" (no quotes, of course).

Test that commander attached to one of your subs and see if it boosts the attack odds any.

[prattaa]

What's missing is the chance of scoring a critical hit. It was a great feature of Pacific General back in the day. That would really make submarine and naval operations in general shine and add a needed bit of realism. I know OOB is not a Panzer General clone but sometimes a good idea is just a good idea.

pacgen.jpg (598.56 KiB) Viewed 4449 times

[Horst]

I don’t get it either why there is a torpedo-defense bonus (submarine_defense) for commanders but no bonus for torpedo-attacks (naval/air). Submarine_attack is the depth-charge attack bonus. It won’t help against surfaced subs.
The naval_defense bonus also helps versus depth-charges… not that someone would ever consider putting a commander into a submarine.

[PoorOldSpike]

..if you look through commanders.txt, there are plenty of references to "naval_attack" and "naval_defense" but not "torpedo_attack" or "torpedo_defense."..

Interesting, I suppose I could tweak files to see what effect it has, but I never do that because I prefer to always stick with out-of-the-box vanilla OOB with no tweaks or mods etc of any kind so people will know I'm singing from the pure vanilla songsheet and nothing else..
"I am constant as the northern star,
Of whose true-fix'd and resting quality
There is no fellow in the firmament."
Shakespeare: Julius Caesar (III, i, 60 – 62)

[bru888]

I don’t get it either why there is a torpedo-defense bonus (submarine_defense) for commanders but no bonus for torpedo-attacks (naval/air). Submarine_attack is the depth-charge attack bonus. It won’t help against surfaced subs.
The naval_defense bonus also helps versus depth-charges… not that someone would ever consider putting a commander into a submarine.

Good eyes, Horst! Yes, indeed, there is one commander with submarine_defense but, as you pointed out, it seems to be for a surface fleet commander only, versus submarines:

Image0089.jpg (169 KiB) Viewed 4456 times

You say that you know of a submarine_attack bonus and it, too, is for surface fleet commanders and depth-charge attacks? Somewhere you have indicated how you know of such things, so I will take your word for it.

So, do you know if there is a torpedo_attack bonus as well? If so, I am sure that we can persuade Spike to temporarily overcome his vanilla scruples in the interest of research and the advancement of OOB knowledge.