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Torpedo Damage and You

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If you expand the Survivability tab of some ships, you may have noticed something called Torpedo Protection listed in it.



Torpedo protection here refers to torpedo bulges, bulkheads, and the like.


As for how it works, well the tooltip seems straightforward enough... or is it?

Lets give it a test.



Here we have the Smith, equipped with 3x1 Bliss Leavitt Mk7 mod. 0 torpedoes. For many reasons, it is my favourite DD, one of which is that I can use it to test torpedoes by launching them one by one instead of sending multiple torpedoes in one salvo. It makes conducting SCIENCE!!!!! easier.


Looking at the stats of its torpedo armament we see that the maximum damage it can deal per torpedo is 6033. However, it is not telling the whole story.


I will elaborate on this later, but for now lets just take it at face value and assume that when it hits the midsection of a South Carolina (Hull B) its Torpedo Protection, rated at 19% damage reduction, will bring the damage down to ~4887.



4445 damage. 442 HP difference. Close, but no cigar. That's more like ~26% reduction. If I shoot at at the same spot multiple times I will still inflict 4445 damage per hit until the ship sinks, So what gives?


Datamining to the rescue! Torpedoes actually have two hidden stats, alpha damage and base damage. For the Bliss Leavitt Mk7 mod. 0 in particular, its alpha damage is 16300 and its base damage is 600. But how does this translate to the 6033 figure we see in-game? Well the formula is as follows (thanks to IKU19): alpha damage/3 + base damage

Why this convoluted way of displaying torpedo damage in-game? I can only speculate, but it's not really important right now.


In any case, the alpha damage is the "true" maximum damage of the torpedo. Except that you would never deal maximum damage with it. Torpedo damage works in a similar manner to damage inflicted by shells. In case you don't know the details or have forgotten, you can read up on it in the damage mechanics thread.


Basically, a penetrating hit (and torpedoes will always penetrate) will deal 1/6th of the projectile's damage to the section it hit and another 1/6th to the body section (which is the whole ship). So in total, 1/3rd of the torpedo's alpha damage would be inflicted upon hitting any part of a ship that is not covered by Torpedo Protection. Using the Smith's torpedo again, we can calculate it as 16300/3 = 5433.33 damage. Now reduce it by 19% due to South Carolina's torpedo protection and we get 4401 damage. There's still a very small amount of damage unaccounted for, which seems to be a common occurrence in other tests against other ships using the same torpedo.


Against Kawachi (both hulls 13% damage reduction)

Expected damage = 4727

Actual damage = 4775


Against Wyoming (hull A 13%, hull B 16%)

Expected damage (hull A) = 4727

Actual damage = 4773

Expected damage (hull B) = 4564

Actual damage = 4584


Against Myogi (hull A/B 0%, hull C 34%)

Expected damage (hull A/B) = 5433

Actual damage = 5469

Expected damage (hull C) = 3586

Actual damage = 3627


Against Montana (37%)

Expected damage = 3423

Actual damage = 3475


Against Yamato (55%)

Expected damage = 2445

Actual damage = 2492


The extra damage seems to be consistently around 30~50 HP. I can only hope it's due to rounding error.




Anyway, who cares, just as long as it reduces incoming damage, right?


But wait, there's more!


What if the best way to reduce incoming damage is to take the hit on a section that is not protected?


Sounds crazy, but those of you already familiar with damage mechanics, especially regarding damage saturation, probably already know what I'm getting at.


The bow and stern are not covered by the Torpedo Protection. Obviously, they should take more damage than the protected midsection. However, once the bow or stern turns black like in the image above the section is considered saturated, and the damage it receives from then on is halved. This is due to the section having run out of Hit Points, and only the Body section is left to take the damage. In other words, a blackened bow/stern will only take 1/6th of the torpedo's alpha damage. It's even possible for the Body section to also run out of HP before the ship sinks and further hits to the same section will result in 0 damage, but this is an extremely rare occurrence.


Furthermore, the bow and stern typically has very small HP pools. Even the mighty Yamato only has 7800 HP in its bow and 7300 HP in its stern. A single Type93 mod. 3 torpedo from a Shimakaze is enough to instantly deplete the HP of Yamato's bow or stern. In the case of Smith's much weaker torpedoes, it took 3 hits (5399 damage each) to deplete the HP before damage is halved to 2699 per hit.


In case you're confused about the maths, here's the breakdown for it:

  • Yamato's bow has 7800 HP.
  • Recall that damage is actually half to the bow and half to the body.
  • First hit deals 2699 damage (rounded) to the bow and 2699 damage to the body. Total damage that pops up is 5399. Bow now has 5101 HP.
  • Second hit pops up 5399 damage again, bow reduced to 2402 HP.
  • Third hit pops up 5101 damage, 2402 damage was inflicted to the bow reducing to 0 HP. Body continues to take 2699 damage as it has a huge HP pool.
  • Subsequent hits to the bow results in 2699 damage each time.


Once the bow or stern is saturated, it will keep taking 2699 damage per hit from Smith's torpedoes, which is slightly more than the 2492 damage it takes by getting hit in the midsection. Keep in mind however, that the Yamato has the best Torpedo Protection currently available in-game. Most ships with Torpedo Protection don't even come close to what Yamato has.


If we use the Montana as the test subject instead (with 37% damage reduction, which is still quite respectable), torpedo hits from the Smith to its saturated bow or stern will also result in 2699 damage. Which is 724 less than a hit on its protected midsection. So it appears to be a good idea to take hits on the bow or stern instead as long as you're not using the Yamato.


There are other good reasons for taking torpedo hits in the bow or stern instead of the midsection. 50% of torpedo damage inflicted to the bow or stern can be recovered by the Repair Party consumable*. A torpedo hit to the midsection on the other hand actually inflicts almost all of its damage to the citadel! For battleships, damage to citadels is only 10% repairable, for cruisers it is only 33% repairable. A hit on the midsection may also incapacitate the engines.

*A small caveat: once repaired, a section that was saturated can be damaged again


There is however one advantage to taking torpedo hits in the midsection. The Torpedo Protection also helps to reduce the chance of flooding to occur, so if your Damage Control Party consumable is on a cooldown, it might be a safer bet to take it in the midsection.


It goes without saying that ships without Torpedo Protection, especially destroyers, should avoid getting hit in the midsection at all costs.




In the end, one has to ask what is the practical use of all this information.

To be frank, not much. But at least you'll know the why and how of it.


If I could choose where to take a torpedo hit, I'd choose to not get hit at all in the first place. In an actual battle, if you are forced to take a hit, you would have very little control in determining where the torpedo will connect.


So what's the point of this thread?

I guess I just love wasting people's time.



Stay safe everyone, and remember to use the WASD h4x.


  • Cool 7

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Super Tester
1,062 posts
11,587 battles

This is actually very informative, and would explain some of the damage numbers I see when using torpedo bombers (since they usually hit multiple parts per drop).

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Super Tester
7,897 posts
8,553 battles

Not really a wasted time. Although I hardly have any control over where I get hit, it is still nice to see that math holds. However, despite of all this, I will still like to take it on my battleship's midsection if I can't avoid. Simply because, DOT is much more problematic than saving few hundred HP.

Edited by icy_phoenix

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1,452 posts
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*Sees long, informative paragraphs full of technical information*


"Hmm, this is actually quite useful! This boils down to hitting the bow and stern for good damage until they go black, midsection hits deal less damage, but aren't as recoverable"




*Sees enemy ship*

*Fires wide torpedo fan*

*1/9 torpedoes hit, doesn't matter where*

"Das is gud"


*Sees wall of incoming, undodgeable torpedoes as a BB*

*WASD Hacks*

*Processes where getting hit would be best*



*Panics even more*

*Hopes WASD hack worked*

*WASD hack intensifies from panic*

*1 torpedo away from death*

*Sees next wave of torpedoes*


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Super Tester
1,041 posts
7,773 battles

This was a good read. I understand now why torps do more dmg against some ships compared to others. 


Should sticky this in the new comers or information areas

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