[TEC] Depth Charge values examined in S3D

[tater]

DCs have a zon file which determines their damage, and a sim file which determines a few other aspects of them in game.

Sim values are:

fall_speed = 3
detonate depth = 25
depth precision = 5

Then stuff related to the shaking of explosions (not damage) and the visual effects.

Fall speed is in m/s I think (and is too high, but dropping it increases chances of sinking the ASW ship)

Depth precision is the error (in meters) of drops made (presumably the error varies based upon crew skill?)

Detonate depth... wtf is it? the _X DCs (thrown) are set to depth 2500. Is that the max depth they fall to?

25 is actually more shallow (in meters) than jap DCs could really be set, even early in the war, and they do seem to drop much deeper. Is the value unused?

tater

[tater]

I changed the detonate depth to 1, no change that I could observe.

Hmmm, I wonder if it has to do with the depth SETTINGS. meaning I should try setting it to 30, with a precision of 1, then set my depth to 45m, and see if they only explode at 30 +-1 or 60 +-1.

tater

[tater]

That doesn't seem to work, either.

Seeing as I was trying to get DCed, and I watched with external camera, I noticed that DCs are non-interactive. Meaning they can (and did) actually detonate inside my hull. Perhaps I need to make the same changes to dc x h as well. I notice that dat has a model, and the regular one does not.

That got me thinking.

I wonder if we could add a collisionable node tothe DCs. Meaning that they would hit the hull and bounce off. They'd still detonate when they were supposed to, but imagine the feeling of being DCed, hearing "Splash! Splash! Splash!" then "boom. BOOM. Klunk, scape... BOOOM!"

hehehe

[GerritJ9]

If fall speed is in m/sec and is too high, reducing the sinkage rate would actually give a ship MORE time to get away before the charge reaches its detonation depth.
Not sure what detonation settings were available to IJN depth charges, but "O.20" was attacked in fairly shallow water off Kota Bharu in December 1941 and tried to escape by creeping away just above the bottom at about 42 metres. Depth charges exploded well above her (about 30m)- apparently the next setting would have meant the depth charges hitting the bottom before they could be set off so it would seem that, at least in 1941/early 1942, the settings available to the IJN were widely spaced, perhaps in the order of 30-60-90 metres?

[tater]

Yeah, from what I've read it was 30, 60, and (later in the war) 90m.

I know the slower sink rate SHOULD work as you suggest, but I thought redwine said he tested as part of die slowly, and they were blowing themselves up. I may be wrong about that, I thought I read it, and I haven't had time to test. Perhaps he made a larger depth error.

tater

[Redwine]

Originally Posted by tater

Yeah, from what I've read it was 30, 60, and (later in the war) 90m.

I know the slower sink rate SHOULD work as you suggest, but I thought redwine said he tested as part of die slowly, and they were blowing themselves up. I may be wrong about that, I thought I read it, and I haven't had time to test. Perhaps he made a larger depth error.

tater

Nop... Tater... i think so the DDs blowing up them selves was caused by a conjuction of two thing... the first, may be the depth error, if you put a big depth error, and the DD launch a depth charge with shallow setting.... in example, 15m ....and the error is 15m, it can explodes just at surface causing damage to the DDs.

But after many test i note this happens when the DDs launch a shallow setting, and plus... he is stopped by some reason, in example to avoid colision with another ship....

What can i say about this... may be real... if a DD launch a depth charges at shalow depth, and do not move away from the launching point, it may cause damage.

In the last test of Die Slowly (Stage 22) i have reduced the previous depth errors.... i cant remember what is the value i am using now, but i reduceed it. At prsent i have not DDs taking damage by themselves.

Using a large depth error, it seems to not be exactly an "error" it seems to work as an "depth spread" value.

It is not bad... for the DD, because if you attempt to evade it changing depth at last moment. the big depth error introduce a spread capability, and depth charges explodes at many diferent depths...

Any way, the Dds taking damage by them selves limits this option, i reach a good valur at ... (not sure now) may be 25m.

Fall spees are a chice, but the DDs calculates the impact point with the new fall speed setting, any way it gives you a more small chance to maneuver away, but only if you are too depth.

Detonate depth... i am not sure if it works, but seems to be the air launched depth charges detonation depth....

Hope some of this can help....

[mrbeast]

Originally Posted by tater

That doesn't seem to work, either.

Seeing as I was trying to get DCed, and I watched with external camera, I noticed that DCs are non-interactive. Meaning they can (and did) actually detonate inside my hull. Perhaps I need to make the same changes to dc x h as well. I notice that dat has a model, and the regular one does not.

That got me thinking.

I wonder if we could add a collisionable node tothe DCs. Meaning that they would hit the hull and bounce off. They'd still detonate when they were supposed to, but imagine the feeling of being DCed, hearing "Splash! Splash! Splash!" then "boom. BOOM. Klunk, scape... BOOOM!"

hehehe

I read about the happening somewhere can't remember where though, the crew could hear the DCs rolling down the side of the conning tower! I also recall an instance where a sub or U boat surfaced and had a dud DC caught on the deck casing! How about opening the hatch and seeing that little baby sitting there?!

[I-25]

Originally Posted by mrbeast

I read about the happening somewhere can't remember where though, the crew could hear the DCs rolling down the side of the conning tower! I also recall an instance where a sub or U boat surfaced and had a dud DC caught on the deck casing! How about opening the hatch and seeing that little baby sitting there?!

This happened to the I-176 North of Rabaul in 1943 after dropping off supples and evacuating wounded solders from finchaven. The XO said that one night a B-25 suddenly came out of the sky and they crashed dive under a hail of 50 cal. fire at about 20M down they heard a thump and a small boom like a firecracker. they came back up after a few hours and as they opened the hatch in the tower the first guy out must of freaked out. the charge was laying inside the tower bridge. they say some sort of yellowish substance was around it. the detonator had gone off but it didn't set off the main charge. Lucky Lucky japs!. On that same mission while at finchaven they got bombed by more B-25's while in the bay at night, the Capitan got shot (not mortally). and the XO beached the sub on a reef. after plugging up all the holes over night they waited for high tide to get the sub back off, high tide came and the sub wouldn't budge. then came the order from the bridge "all hands on deck". from atop the tower the XO ordered with a megaphone "Ok now, everybody run from one side of the boat to the other" and by god knows how Japanese ingenuity worked and the boat started rocking and they got it off!

[tater]

I just read Japanese Destroyer Captain: Pearl Harbor, Guadalcanal, Midway - The Great Naval Battles As Seen Through Japanese Eyes.



Anyway, he mentions dropping charges (early in the war) set to 50m. Totally different than the only other info I had from navweaps.

Hmmm.

[Fincuan]

Originally Posted by tater

I wonder if we could add a collisionable node tothe DCs. Meaning that they would hit the hull and bounce off. They'd still detonate when they were supposed to, but imagine the feeling of being DCed, hearing "Splash! Splash! Splash!" then "boom. BOOM. Klunk, scape... BOOOM!"

hehehe

With the current collision sounds, that would of course go like this: "splash! splash! splash!" -> boom, boom, SCCREEEETTTCCCHHH SCCCRRAAATTCCCHHH! (imagine the rubber boat colliding with your sub)

[hyperion2206]

I remember one incident were I was DCed by a minesweaper and I came to PD to kill him. Just as I reached PD the minesweaper dropped DCs but then he noticed that I was at PD and backed up. The end of the story: He'd blown his DC racks up, but was otherwise undamaged.

[tater]

Sounds like the depth precision should be set to be fairly accurate. The detonation depth doesn't seem to do anything that I can tell.

It's odd, the hedgehog has the depth set to 2500 and the precision to 300. Their area of influence is ~2m, do they blow on contact? If that was the case, then the super deep detonation depth would be to give them time to physically hit a target. Odd that the depth value has no effect though. I set it to 1m, and they dropped fine. I set it to 30 (precision 1m), and they blow at various depths.

I have tried the radius dropped to 8m, and they can DC you for ages and not damage you---at least not enough to get the crew to say we're taking damage.

That might give the desired effect of being held down, and attacked with many DCs, but still surviving (which seems accurate to what US subs experienced in the PTO.

tater

[tater]

BTW, I think the DC_X_H is the hedgehog, right?

The RL Type 95 had a 100kg warhead, 2 depth settings (30 and 60m), then a 3d setting in late versions (90m). It had a sinke rate of 1.9. Interestingly, they also shipped parachuted versions---not dropped from planes, but a chute to slow the sink rate farther for slower ships to drop them at shallow settings.

This makes me want to mod in some new DCs. Make an early war in 2 versions, one with -1.9 sink, and one even slower for various ersatz ASW assets.

They Type 2 came into service in 1943, and had the sink rate we see in SH4, -3m/s. Some were ~100kg, others 162kg warheads. Looks like it could be set to finer depth control (~25 ft intervals)

They also armed ships (even merchants) with ASW mortars. I wonder if we could mod a hedgehog that fired a single round instead of a pattern...

tater

[Lagger123987]

Originally Posted by tater

BTW, I think the DC_X_H is the hedgehog, right?

tater

Right

[skwasjer]

This is the definition of the amun_DepthCharge controller/structure, in the new S3D version (taken from SHSim.act).

/// <summary>
/// The under water falling speed [m/s].
/// </summary>
public float fall_speed;
/// <summary>
/// The detonation depth [m].
/// </summary>
public float detonate_depth;
/// <summary>
/// The depth sensor precision [m].
/// </summary>
public float depth_precision;
/// <summary>
/// The explosion range [m].
/// </summary>
public float explosion_range;
/// <summary>
/// The explosion impulse [t*m/s].
/// </summary>
public float explosion_impulse;
/// <summary>
/// Water hit splash effect.
/// </summary>
public ulong splash;
/// <summary>
/// Water bubbles effect.
/// </summary>
public ulong bubbles;
/// <summary>
/// Water column explosion effect.
/// </summary>
public ulong water_explosion;
/// <summary>
/// Under water explosion effect.
/// </summary>
public ulong under_explosion;
/// <summary>
/// Above water explosion effect.
/// </summary>
public ulong above_explosion;