RA mod 1.41 with Patch #1 and #2

[jaop99]

I have the latest RA mod 1.41 with both Patchs.

I was playing in an Akula vs an Oscar II and looks like he detected me and launched two Shkval torpedoes, because the where "flying" at 189 knots underwater, ok, no ping from them only a lot of noise, but both torpedoes exploded more than 200 yards from my sub and they crippled me, unless the torpedoes were carrying a nuclear warhead, the standard 210kg warhead should not damage my sub from this distance, any idea? (post video below)

[ikalugin]

If Shkvals were not pinging you they were nuclear.

[FPSchazly]

I did a back-of-the-envelope calculation of this at one point, and yes, 210 kg of conventional warhead at that distance shouldn't really do any damage to you. It seems they do model the damage from Shkvals at nuclear energy levels.

[p7p8]

Shkval have only MAD sensor - it not pinging.

On map you have positon center of your sub, so second shkval almost hit you directly.

For distance measuring (and bearing) press "r" on map. Works also in replay window.

BTW vanilla campaign is not compatibile with RA

[p7p8]

Originally Posted by FPSchazly

I did a back-of-the-envelope calculation of this at one point, and yes, 210 kg of conventional warhead at that distance shouldn't really do any damage to you.

Can you describe methodology of your calculations?

[jaop99]

Hi guys, my calculation method is very simple, in the replay map there is a scale in the bottom left corner, the scale was 500 yards, then both torpedoes exploded about the 200 yards far, period!, thats why I'm asking if the Oscar II had nuclear warheads in any of the vanilla missions. The second torpedoe exploded about 150-180 yards, a 210kg warhead is not enough to do anything to a big sub from this distance!.

[p7p8]

I asked about calculations for those:

210kg warhead is not enough to do anything to a big sub from this distance!

and

210 kg of conventional warhead at that distance shouldn't really do any damage to you

I think DW have very simple model of damages (you can still run with 99%). Your sub had only 45% of damage - it means many systems needed a lot of time to repair.

Your sub had course 010 deg. and shkval exploded near 175 deg from center of your sub. Akula III have aprox. 123 yd of lenght, so you should subtract 60 yds from first measurement (200 yds)

I think it is close enough for damaging of some systems.

BTW: For accurate range measurement you can use "r" key on map.

[jaop99]

Take any calculation of a bigger airborne warhead IRL, for example FAB-250 or RBK-250, in the air where there is not almost no density, the shrapnel can reach about 400+ meters away, but the blast and expansive wave's real damage is about the range of 200-300 yards. Now, any explosion in the water, is more difficult to reach farest targets due the density of the water, and the pressure depending the depth where the bomb exploded.

In WWII the depth charges had from 400-3000 pounds (400 pounds were the used in mortars) but even with this payload, the explosion should be close to the sub to make a real damage.

http://www.engr.psu.edu/cde/Short/MP...-Dam-Ass-1.pdf

[jaop99]

Originally Posted by p7p8

I asked about calculations for those:

and


I think DW have very simple model of damages (you can still run with 99%). Your sub had only 45% of damage - it means many systems needed a lot of time to repair.

Your sub had course 010 deg. and shkval exploded near 175 deg from center of your sub. Akula III have aprox. 123 yd of lenght, so you should subtract 60 yds from first measurement (200 yds)

I think it is close enough for damaging of some systems.

BTW: For accurate range measurement you can use "r" key on map.

Yeah I agree it could take damage, but in the game they were massive!, I think that Crazy Ivan changed something in the damage model of the Shkval from the previous version.

[FPSchazly]

Originally Posted by p7p8

Can you describe methodology of your calculations?

My methodology is very simple. Let me start by saying I know nothing specific about how explosions work, but I was intrigued by this passage on a Wikipedia article on depth charges:

Originally Posted by Wikipedia

The killing radius of a depth charge depends on the depth of detonation, the proximity of detonation to the submarine, the payload of the depth charge and the size and strength of the submarine hull. A depth charge of approximately 100 kg of TNT (400 MJ) would normally have a killing radius (hull breach) of only 3–4 meters (10–13 ft) against a conventional 1000-ton submarine, while the disablement radius (where the submarine is not sunk but put out of commission) would be approximately 8–10 meters (26–33 ft). A larger payload increases the radius only relatively little because the effect of an underwater explosion decreases as the cube of the distance to the target.

Using this information, I used an equivalence to determine the kill and disablement ranges for a 5 kt nuclear warhead. 100 kg of TNT ~ 0.1 ton.

0.1 ton / (3 meters)^3 = 5000 / (X meters)^3

(I'm basically saying 0.1 ton divided by 3m^3 is equivalent to "kill", so I set 5000 ton / X meters ^3 equal to that and solving for X. This is nothing more than a simple extrapolation.)

Solving for X produces a killing range of approximately 110 - 150 m and a disablement range of approximately 300 - 370 m.

Let's discuss my assumptions. I'm assuming a large nuclear sub (~7000-10000 t displacement) behaves similarly to a 1000 t conventional sub in response to explosive damage. This is probably not a good assumption, as smaller objects tend to be stronger than larger objects due to the square-cube law; however, the larger nuclear submarines also have more mass to absorb explosion energy. I am not sure which would be the dominant effect.

These numbers on Wikipedia also have no citation, so I'm not sure where these kill and disablement ranges come from. However, assuming the numbers are correct, I was just curious to see what the numbers would be assuming a nuclear-sized warhead and extrapolating using a simple method. It's an interesting result, it's not one I would expect, and suggests more investigation.

That Wikipedia article also discusses more effects, such as primary and secondary shockwaves, the depth of the explosion, explosion shockwave reflections off the bottom of the ocean, and other things that are not considered in my simple calculation.

Originally Posted by jaop99

Yeah I agree it could take damage, but in the game they were massive!, I think that Crazy Ivan changed something in the damage model of the Shkval from the previous version.

Based on my experience in vanilla and RA, the Shkvals are about equal in damage in both versions. I haven't seen anything to suggest the RA Shkvals are more damaging.

[jaop99]

I agree with you, if the Oscar used nuke torpedoes, the damage I received is fair!, and I remarked this from my first post! and by the way, most of the russians subs have double hull with materials that were a dream in the WWII.

Wiki about Akula:

"The Akula incorporates a double hull system composed of an inner pressure hull and an outer "light" hull. This allows more freedom in the design of the exterior hull shape, resulting in a submarine with more reserve buoyancy than its western analogs. This design requires more power than single-hull submarines[citation needed] because of the greater wetted surface area, which increases drag."

[p7p8]

Thx for explanation Chazly

Yeah I agree it could take damage, but in the game they were massive!

45% of damages are not "massive". Like I said before, in DW 99% of damages allows you play well after repairing (1-2.5 hours). I think 100% of damages means that your sub is not controlable anymore ...and from that moment is sinking. This is something different than "completly destroyed".

BTW double hull is not inner hull + external "armor".

[FPSchazly]

Originally Posted by p7p8

Thx for explanation Chazly

You're welcome!

BTW double hull is not inner hull + external "armor".

Yes, the internal hull is the pressure-bearing hull. The outer hull is for hydrodynamics, and also forms the outer boundary of the ballast tanks.

[ikalugin]

The increased strength of the hull structures and the boyancy reserves typical for Soivet desighns (not all of them, but such reserves were standard) improve survivability.

For example if a single compartment is flooded on LA class you are dead, if a single compartment is flooded on Akula you may still have a chance.

[p7p8]

Yeah, Russian/Soviet nuclear submarines are much more stronger and safer than american subs but they just have "bad luck"

sunken nuclear submarines