# Naval Projectile Fragmentation Damage: What’s New?

In this article, our naval designers will be talking about the new modeling of fragmentation damage from naval projectiles that were introduced to the game with the release of the Alpha Strike major update.

In summary: Naval projectiles have had their fragmentation damage changed in the Alpha Strike update, where before the maximum number of fragments produced was smaller than it could’ve been due to performance constraints. Additionally, before we also had to manually configure the damage fragmentation of each naval projectile. We’ve now developed a new system for this that has given us better flexibility when calculating the number of fragments without a loss of performance, allowing us to also increase the number of fragments produced. Upon doing this however, some ships have been taking increased damage due to geometry issues, where many have been fixed already. We’ll be keeping an eye on your feedback for any other problems that may occur, and fix these issues where needed.

Types of damage and what they depend on

All naval projectiles in the game cause three types of damage: kinetic (depending on the mass and speed of a projectile), high-explosive (depending on the mass of the explosive), and fragmentation (depending on the speed and mass of the projectile, the mass of the explosive, as well as the filling coefficient of the projectile, such as the ratio of the mass of the projectile body to the mass of the explosive). In War Thunder’s naval battles, projectiles of different types are used which as a rule, cause combined damage of several types.

The changes to the damage model of naval projectiles has only affected fragmentation damage, where it’s this damage that we’ll be talking about today in this article.

Why did we make changes?

Until the Alpha Strike update, the calculation of fragment damage had two important shortcomings. Firstly, due to a problem with reduced performance when calculating the formation of a fragmentation field, the maximum number of possible fragments for each projectile was greatly reduced. Let’s say that in reality, a shell is capable of generating up to 3,000 fragments, in the game it produced no more than 200. Calculating even this volume of fragments from shells from several salvos at once at each given moment of a naval battle meant sharp drops in FPS, which we want to avoid.

The second problem follows on from the first, where in these conditions we were forced to configure each projectile manually. This means that each naval shell model was configured according to several parameters such as armor penetration of fragments and the maximum distance of their scattering across all areas of the formation of the fragmentation field. Doing this is a long and labor-intensive process, and very vulnerable from a balance point of view, as it’s easy to inadvertently strengthen or weaken a projectile without meaning to.

How did fragment damage work before the Alpha Strike update?

Let’s take a look at how fragmentation damage affected ships before the recent update. Take for example a high-explosive fragmentation projectile with an instantaneous fuse. When hitting an object, the fuse detonates the explosive charge, which leads to an explosive sphere. As noted earlier, medium and large-sized shells produced about 200 fragments. This explosion sphere has the following parameters: armor penetration (breaking), size and damage. If the force of the explosion is sufficient enough to penetrate through armor, high-explosive damage is inflicted on all modules located behind it and falls within the radius of the sphere of destruction. Additionally, fragments from part of the nose cone also rush into the gap that was formed — about 10-12% of the total number of fragments that the projectile is capable of forming (only about 20 pieces) go through the penetrated armor. If the force of the explosion is not enough to break through armor, the fragments will not form behind it.

Once behind armor, fragments of the nose cone can strike either a ship module, the next armor layer or part of the structure. Having their own armor penetration parameters, fragments can penetrate the next armor layer or be stopped. At the same time, penetration decreases depending on the distance and previously broken armor.

When the armor is penetrated and a breach is formed, fragments scatter in a cone with an opening angle of 60 degrees. They hit anything in their path at different angles of deviation from the normal. Some of them are unable to break through more armor, and some do not hit it at all. As a result, any functional module of a ship that found itself opposite of the shell explosion receives less damage than the entire nose cone could inflict. Of the 20 fragments that penetrated for example, less than half could have hit a module, say about 8.

Overall, we’ve had to manually adjust the parameters of the fragmentation effect. With a known, small number of fragments that could cause damage to modules, the damage from one fragment could be high in order to maintain an adequate ratio of fragmentation damage to all other types of damage that a projectile has. However, the maximum damage of one fragment wasn’t made too great so that the total fragmentation damage of any of the cones did not exceed the high-explosive or kinetic damage of the entire projectile.

Is it right now?

Yes, fragment damage is now working correctly. We’ve developed a new system for calculating fragments, which allows us to give each projectile as many fragments as it’s supposed to according to its performance characteristics and do this not only without loss of performance, but in some cases even with an improvement.

A couple of years ago, we transferred the calculation of armor penetration shells to the Jacob De Marre formula, making it possible to obtain a uniform approach to calculating armor penetration. With this new system for calculating fragments, we get exactly the same automated approach to each projectile.

The maximum number of fragments, their armor penetration, damage and dispersion range are now calculated automatically. The difference in these parameters between for example 100 mm and 305 mm shells have become much closer to reality and in general have become much more accurate.

In the same situation as described above, when a shell explodes on armor, 50-100 fragments go through the penetrated armor, rather than 10-20. There’s now more chances to hit a module located behind armor, as more fragments that went through armor will hit that module.

The parameters of armor penetration, damage and range themselves have changed unevenly. For some shells, they’ve increased a little, for some they’ve decreased a little, but the maximum number of fragments for all naval shells has increased proportionally.

The fragment sections of a naval projectile has also changed somewhat. There’s three sections that can be distinguished: the front, middle and rear end. The nose cone at the front which has an angle of about 60 degrees contains up to 15% of all fragments that a projectile can produce. In the mid section, there’s up to 75%, and the remaining amount is at the rear end.

All other types of damage remain unchanged: kinetic, explosive damage and pressure damage has not changed. HE shells with a flash fuse no longer penetrate more, instead they begin to cause more fragmentation damage.

Addressing your feedback: with the new damage, can a ship be destroyed in one shot?

After the release of the Alpha Strike update, we’ve received feedback that a large ship could be destroyed by obviously weak shells, for example 100-120 mm. There was also feedback that some ships were destroyed after being hit by one shell.

When we saw this, we immediately began inspections and identified several ships that had errors in their geometry. For example, the Arizona and Hyuga could have their magazines detonated by a hit from almost any projectile in the area of the elevator under the main caliber turrets. The damage passed through the elevator, causing a fire that spread to the ammunition cellars. Mutsu’s bow magazine could detonate from a shell burst on the hull near the waterline. Similar errors were observed in several other ships. We’ve carried out prompt work to correct the errors that have been found, meaning all known issues are now fixed. We’re continuing to monitor your feedback and will try to promptly fix any other issues found. If you’ve experienced some issues, creating a report on our bug reporting platform will greatly help us reproduce them and apply a fix. Please make a report here.

Is it true that auxiliary caliber shells have become more effective than main caliber shells?

A ship’s armor works properly and does not allow the shells which cannot penetrate or break through to do so. HE shells have not received any more armor penetration.

Having said this, we found a bug where in one very specific combination of events, a projectile could hit the underside of a ship, where there’s little to no armor. A fix for this was released in a very recent update, so this should not be occurring again.

We’re going to be reviewing the algorithm for generating kill-log messages and the set of information in it. We’re also planning to provide more detailed operational information about the damage a player inflicts on an opponent during a match, and we hope this confusion will soon be corrected.

The War Thunder Team

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so how long will BR changes lag behind the damage changes?

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“…some ships have been taking increased damage…” is the understatement of the year! .

Good to see an official in depth review of the background, changes, issues, and actions taken, all very logical and what many players expected had happened.

It’s just a pity that’s its taken 2 weeks to have a front page acknowledgement there was a problem at all. Still need to work on that customer service.

Current battle experience is what was expected from the fragment changes rather than what we got. HE is now doing some damage to internals, but not ignoring armour entirely for catastrophic effect. Neither useless nor OP, and just as importantly still leaving a role for SAP & AP for tougher opponents.

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Blancing high rate of fire ships against the low ones would be nice. Currently standard 4.3 destroyers have no chance against stuff like SKR or standard 5.3 cruisers have no chance against sttuff like Atlanta and these changes made it even worse to become target of one of those ships. Doing more damage to them doesnt matter when theres no time for you to deal it.

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Are they also plans to remove artificial dispersion increases like we see with all the 15" guns?

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40mm bofors as seen on PT-808 and PT-15 in Japanese tree feel very sad and weak in matches… I wonder if this is intended? Even the 25mm guns on Type T-51b feel better to use, and KO faster…

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@Stona_WT you forgot a word, it says “is it now?” instead of “is it working correctly now?”

unless its correct

What’s new? Nothing basically,

Testing Yamashiro as example, EVERY Yamashiro i saw in 1 game of playing got one shot EVERYTIME including 2 of mine and multiple others i saw around. Granted this was big caliber shots, still this doesn’t feel right at all.

EDIT: after playing 2nd game, I’ve only seen 100% ammo rack kills, most on first decent hits.

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Thank you so much. It’s nice to know that, as opposed to what 99% of the community says, naval is heard by Gaijin and the developers try their best to improve the gamemode as soon as possible and in the most effective way.

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^^^This is the key.

Before the fix we started to see players bringing destroyers and cruiser from multiple nations in battle (especially the japanese ones that have only HE), now it just reverted to the usual all american and SKR-1/7+Pe-8 lineups around 4.3-5.7, then you switch to Sharn and russian BBs due to the fire rate and the punch that they pack with each shell.

Atlantas are murdering 4.3-5.3 games, packs of SKRs are sealclubbing all new payers that see their reserve DDs melted in a few salvos (and if you manage to sink one you are granted a 5000kg revenge bomb in return).

With the new changes DPM machines are even more powerful and you really feel the extreme compression and the obvious meta of each tier.

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Thank you War Thunder Team for the time and effort you have dedicated to improving the naval game mode, and thank you for the detailed breakdown.
We appreciate your passion and effort very much. Keep up the good work!

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A well put together post, and I’m glad the new system is sticking around; a few (severe) bugs in the patch aside, it’s an excellent change. :)

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Appreciate the transparency and explanation, this was a good post.

And it’s good to see you’ve laid out the solution to it too.

Only thing we need is BR changes, some already under BR’d ships are now even more broken than before.

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Thank you for the detailed explanation of the new Projectile Fragmentation system.

Does the development team have any plans to further develop the current Projectile Fragmentation system so that the size of the fragments produced will vary with the amount of explosives?
In real life, the higher the ratio of the shell’s explosive charge, the greater the number of fragments produced and the greater the local damage, but the smaller the size of the fragments and the lower their penetrating power. Conversely, the lower the ratio of the shell’s explosive charge, the number of fragments produced is low and local damage is small, while the size of the fragments is large and their penetrating power is high.

By varying the size of the fragments produced with the amount of explosive, it is possible to express in the game the meaning of each country’s navy creating shells with low explosive content, and also to improve the balance of ships that use shells with low explosive content.

In the old forums, reports on the amount of explosive and the size of the fragments seem to have been submitted to the developers.

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Improvements to battles are welcome. However, it was a bad decision to make changes to one fundamental aspect of naval battles the day before an naval event vehicle started. Specially when the DEV server was open for very few days and that wasn’t enough time to test this alterations. With the bug it was very confusing to decide what lineups to use, as it seemed to affect all vehicles. I hope you consider this for future updates that clash with event vehicles.

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The problem is that the life time is too short, especially on destroyers. Someone thought about new players. Now examining the tree will be difficult. Capturing points on destroyers is practically impossible. Increasing the fragments causes a proportional increase in the power of the projectiles.

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Could we get a bit of extra clarification on how important the bursting charge is compared to fragments and kinetic impact ?

Playing the Lorraine (24kg bursting charge in the APHE), I honestly don’t feel like I’m dealing more damage than in the Dante Alighieri (5.6kg APHE).

That being said

I want to bring to your attention that the damage changes inherently don’t match well with WarThunder’s current “crew as HP” system. Crew counts being tied to modules means HE is disproportionately effective versus ships that have moderate levels to no armour (makes you wonder why shipwrights ever bothered to slap anything under 100mm of armour), even when landing hits which realistically wouldn’t do much.

I would suggest you keep on the track of higher realism and move away from “crew as HP”, and replace it with unrepairable damage (like we currently have with some hull breeches). I would suggest crew count to remain as only a multiplier in crew effectiveness.

• HE should be primarily causing damage to exposed superstructure weapon emplacements and flooding damage if penetrating close enough to the waterline.
• AP should cause damage to armoured modules, eventually damaging them to the point they cannot be repaired.
• Repair times across the board should be increased.
• Fire localisation should be made more legible for the player.

I would additionally suggest implementing “crew tasks priorities”, i.e. giving the player control of exactly how important they think firefighting, repairing, manning the secondaries and the main battery are important. This would add a large level of player interaction and strategic choices, which naval often feels more lacking in than with aircraft or tanks.
I contend the current “all survive processes demultiplier” mechanic is unsatisfactory because it lacks granularity and player interaction beyond pressing a single button.

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This is good on paper, but there are many issues still.

For example, ships such as Scharnhorst or Nevada keep getting ammo detonations by 100-127mm HE when this shouldn’t be possible. These shells don’t have, even remotely, the power to damage these ships’ citadel armor, and yet, they keep causing ammo detonations, somehow.

Here, for example, this happened just as I was writing this comment; a 130mm HE detonated the ammo on my USS Nevada, which means it or its spall somehow bypassed the extremely thick citadel armor. This shouldn’t be possible in any way.

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I can definitely get behind this. Having completely broken things repair in barely longer than it takes for guns to reload (or sometimes shorter, even) often makes trying to cripple a ship feel like whack-a-mole. (Tanks have the same issue.)

It’s not so bad in 1v1s, but is terrible for one-vs-multiple, as it lessens the ability for a player to cripple one enemy, then leave them for a moment to deal with others.

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Please make a bug report in this case, as some ships might still have geometry bugs with their damage model and this will help developers to filter out ships with similar issues.

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