Why there is a "14.3 Caliber Rule" when calculating the damage?

[mandiokai]

So, I was watching the World of Warships official video explaining about how the penetration and damage works when armor is shot, and this rule suddenly showed up.

"If the armor is thinner at the impact point than a shell caliber divided by 14.3 then the shell won't ever bounce off the armor [...]"

This video:
"How it Works: Armor | World of Warships"
https://youtu.be/yQcutrneBJQ?t=112

And I got curious, why exactly there is a rule for dividing the value of damage for this number in specific?

[Sekhriat]

Here's an answer from a few years ago regarding this; https://www.reddit.com/r/WorldOfWarships/comments/5552bh/is_there_a_realworld_precedent_for_the_overmatch/d88520m/

[Nungunz]

Originally posted by Muskrat:

Ya notice shells just bouncing off of ships.. no points, no credits, no penetration, so waste of ammo.. switch to HE and hope get some points.. but it like a lot bounce 10-15 no hits.. good luck

So there is a range of values for bouncing AP and SAP shells based on the angle of impact of the shell. By default an incident angle of 0 to 30 degrees will auto-bounce, 30 to 45 degrees has a chance to bounce (I think it's a linear scale). However, if the caliber of the shell is 14.3 times the armor thickness, no bounce will occur and normal armor penetration calculations occur (this is called "overmatch).

"Overmatch" is mostly relevant for shooting a ship in the bow or stern as there are several armor thresholds. Example:

Most Tier 6 and 7 battleships have 26mm of bow/stern platting so if your gun is less than 372mm shooting those ships in the nose while they are bow-in (called "Bow Tanking) is pointless because the shells will auto-bounce. If you have 372mm or greater, go nuts, you can probably score a citadel through the bow.

Some of the key thresholds are in the following tables: https://wiki.wargaming.net/en/Ship:Armor_thresholds#AP_overmatch



Please note that there are some ships that do break the rules. For example, US Heavy Cruisers and Super Cruisers have super-heavy AP shells that have improved bounce angles (0 - 22.5 degree auto bounce and 22.5 to 30 potential bounce). British Light Cruisers also have improved bounce angles (0 to 15 for auto bounce and 15 to 30 for potential bounce).

[christof]

I think the main question of the thread opener however was why it's exactly a factor of 14.3 that decides overmatch. Whether there is a real life reason for that, it's a balancing thing. Or the guys in development just grabbed a number of dice and used them to decide (okay, not quite serious about that last one).

[dakin1]

Originally posted by christof:

I think the main question of the thread opener however was why it's exactly a factor of 14.3 that decides overmatch. Whether there is a real life reason for that, it's a balancing thing. Or the guys in development just grabbed a number of dice and used them to decide (okay, not quite serious about that last one).

The 14.3 factor is a balancing feature of the game based on the nose armor thicknesses you see in ships:

25 mm armor * 14.3 = 357.5; any shell larger than 14" will overmatch
27 mm armor * 14.3 = 386.1; any shell larger than 15" will overmatch
32 mm armor * 14.3 = 457.6; any shell larger than 18" will overmatch (meaning, the 460 mm guns of Yamato/Mushashi and the 510 mm guns of Shikishima and some of the new super ships)

The concept of overmatch may have some real world physics behind it, but the factors used in the game exist solely for balancing purposes.

[christof]

Perfect! I think that answers everything.