Impact (AZ) versus Magnetic (MZ)

[Dewgle]

From the B130 patch notes, posted Nov 21, 2021

Originally posted by Ruby:

Rework of the damage model used for NPC ship hulls to on average make torpedoes with magnetic setting (MZ) more powerful than with the impact setting (AZ). Motivation: our testing on medium GRT merchant ships indicated that MZ torpedo had a 65% chance to completely disable a ship, while AZ torpedoes had a 85% chance to achieve that. Counter-intuitively they had the highest chance to achieve this when hitting the waterline as that increased a chance for fire on the target ship's deck. After this rework MZ torpedoes have a 95% chance to completely disable a medium GRT merchant ship, while AZ torpedoes have 70% chance, which should be much closer to reality.

I'm hoping to get some clarification from Ruby, Freek0ly or Nihilcat on this subject if possible. Because the wording of these patch notes seem to imply that magnetic torpedoes deal more damage to the target than impact torpedoes.

I'm working on a YouTube video to explain the differences between impact & magnetic torpedoes to new players and I wish to make sure my information is correct with what the game is actually doing, but of course I also hope that the game is behaving realistically in regards to torpedo detonations.

To clarify what I mean, the magnetic torpedo should not arbitrarily cause more damage to the target than an impact torpedo. All torpedoes carry the same amount of explosive charge inside the warhead. What matters is the depth at which the torpedo explodes, not which pistol it's using.
https://steamcommunity.com/sharedfiles/filedetails/?id=2808264004

Both torpedoes have the same potential to cause damage to a ship. What makes the magnetic torpedo capable of causing more damage is it's ability to explode at a depth deeper than the impact torpedo can reach.

So my question is:

• Do magnetic torpedoes actually cause more damage to ships in Uboat?
  
• And if the answer is yes, can we expect this to be fixed in a future patch?

[schutt]

Magnetic torpedos do the damage twice: First the explode below the hull and do the impact damage, then the hull "sinks" into the bubble created by the explosion and gets damage again. So however it is modeld it might be that magnetic fuse exploding below the ship does more damage than impact impacting on the side.
Second, just as you image shows: magnetic below ship will be at higher depth doing more damage than side impact, again only if that is modeld in game to be a thing and if it makes a diffrence. Specially on heavy warships it **could** be that the lower sidewalls (well below the armor belt) are a lot weaker than the bottom of the ship.

Also i might want to add to your picture: if there is high waves and the ship moving up and down considerably the magnetic torp might fail due to passing to low, as well as the impact fuse when set to low. A rolling ship might cause the impact fuse to hit at an angle that gives a higher dud rate. Here again clarification of the game design would be nice.

So all in all i would totally agree: A clarification of the developers would be really nice, since we can only assume from what would be real physics but not know what and how its modeled in game. I would assume the uboat command has sufficiant test data to put a paragraph into the manual with some explanations of what is assumed the most lethal hits (engine room at halve depth with impace and 1m below ship keel middle of ship?).

[wolf310ii]

Originally posted by schutt:

Specially on heavy warships it **could** be that the lower sidewalls (well below the armor belt) are a lot weaker than the bottom of the ship.

Most heavy warships were build befor WW2 and befor MZ, so they had a torpedo belt below the armor belt, but no torpedo protection on the bottom/keel.
Some ships had double keels, but these were filled with ballast water, fresh water and on ships with oil fired boiler with oil, what reduced the protection against torpedos below the keel.

[Dewgle]

Originally posted by schutt:

Magnetic torpedos do the damage twice: First the explode below the hull and do the impact damage, then the hull "sinks" into the bubble created by the explosion and gets damage again. So however it is modeld it might be that magnetic fuse exploding below the ship does more damage than impact impacting on the side.

Aye, that is how it's supposed to work but the wording on the patch notes:

"After this rework MZ torpedoes have a 95% chance to completely disable a medium GRT merchant ship, while AZ torpedoes have 70% chance, which should be much closer to reality."

-Seem to imply that the devs made magnetic torpedoes arbitrarily more powerful than impact torpedoes by simple virtue that they are magnetic with no mention of any other parameters or conditions involved in the process. It implies that a magnetic torpedo striking the same location as an impact torpedo has a 25% better chance to disable a ship which of course would not be right.

Originally posted by schutt:

Also i might want to add to your picture: if there is high waves and the ship moving up and down considerably the magnetic torp might fail due to passing to low, as well as the impact fuse when set to low. A rolling ship might cause the impact fuse to hit at an angle that gives a higher dud rate. Here again clarification of the game design would be nice.

Both features are already implemented either deliberately or by happy accident. In rough sea states, a torpedo set too low can pass right below the hull without detonating the impact or magnetic pistol. And the angle of impact that can cause an impact torpedo to dud work vertically as well as horizontally based on some of my testing.

Originally posted by schutt:

So all in all i would totally agree: A clarification of the developers would be really nice, since we can only assume from what would be real physics but not know what and how its modeled in game. I would assume the uboat command has sufficiant test data to put a paragraph into the manual with some explanations of what is assumed the most lethal hits (engine room at halve depth with impace and 1m below ship keel middle of ship?).

I can tell you that component damage is not modeled in Uboat but I'm hoping it will be in the future, it's a highly requested feature and the fact that ships can keep steaming along after taking a hit to the engine room or propellers actually annoys a lot of players.

The damage model in Uboat is fairly simple. Each ship has up to 40 compartments according to Shdun (creator of the SPO mod) and Salamander (creator of the Iron Coffins mod).

When a torpedo strikes the hull of a ship, the game performs a calculation to see how many compartments are within the 'bubble' of the warhead's explosive charge. The compartments closest to the center of that 'bubble' will generate the most flooding while the compartments on the outer edges of that bubble will generate less flooding. So in simplest terms, striking a target dead amidships will cause the most amount of flooding.

Striking fore or aft of the ship will cause a lot less compartments be within the influence of that exploding bubble.

[VipreRX]

I thought this change was made by adjusting the internal damage boxes or whatever in the ships after someone pointed out how they were all arranged up near the waterline and the blast from mag torps under the keel were barely reaching them and as a result doing less damage. In short the compartments, either shape or position, were adjusted to make lower shots more potent.