Hit power of torpedoes : US to IJN calculation
 

min

Larger damage radius means more gets damaged.

An explosion happens in the game. In generates a damage value randomly between the min and max value.

It applies 100% of this number out to Rmin, and reduces the damage applied from 100% to 0% between Rmin and Rmax.

The AP complicates things as a modifier.

There is simply no way to scale things in an obvious way without testing since the values are all arbitrary. A "formula" is probably only good as a starting point.

you need to find data on the explosive itself to guage if its equal 1 to 1 with german or us explosive to give you the baseline to determin a 38% increase in explosive is = ? in increased damage.


can you compare DD sinkings on both sides and get any commonalities to do a guestimate on ijn vs us torp damage? the us did have to sink a few DD that were captured by japan and we were forced to sink them.

if you dont get any evidence to the contrary i would use german explosive power values since they were allies and likely sharing the same research

There is no algorithm to do this for you. Really. Not possible.

There is a thread in here that was locked about german torpedo strength vs RFB. I did a little digging, and even though I had assumed that german fish were stronger later in the war, the stats show exactly the opposite (looking at sinkings of similar sized merchant targets).

I think the only way is to look at some sinkings, and mess with it til it feels right.

the problem right now is that although I modded the exact increase in explosive power they do sink ships too easily ingame.

that has to be corrected.

Peabody and I are working on it.

so I will now use the first one as base value and see what gives.

Keltos

Remember it's going to pick a value between minEF and maxEF. If you think that a given IJN fish should always be ~twice as strong then don't have the min value so low, but maybe the max not so high.

It is going to be VERY ship DM related. The AP value is a heavy modifier on the EF, too. Nothing to say but that it will take a ton of testing. Also, I know nothing about the DM fidelity of allied ships, since I've never shot at any.

These topredos should be pretty strong-they were one hit one kill designs, right? The problem might be more a case of if they exploded.

I keep coming across references to unreliabilty in almost everything the Japanese produced in WWII. One of the their top aces was killed when his plane literally fell apart!

It might be a lesser problem with a whole ship as one or two big companies built them, but typically small workshops supplied the components of the weapons and detection systems which were then assembled at the main factory. US quality control experts had a fit in the Korean War when inspecting the huge number of dud shells coming from Japanese suppliers and a crash course in QC wholeheartedly adopted in the early fifties. They "New Japan" factories were designed around it, but during the war QC was literally hit or miss.

Most of this is from books I read a while ago about the rebuilding of Japan so I don't have any references on hand. Have you guys found any references to this in your research? Are seroius breakdowns, duds and malfunctions part of the IJN campaign?

Sorry, I know this isn't helping mod the relative torpedo strengths but the thread got me thinking.....

the values I use are from RL data, they had very good torpedoes with very few duds due to live exercices prior to WWII.

They didn't have to try them out in war as did the americans till 1943...

Peabody and I were wondering if they weren't too strong compared to the hit value of allied ships in game.

keltos

keltos

Before you can use those numbers that were posted in the chart (which didn't copy over when I hit reply BTW. ??) is to find out how much explosive that German Torpedo had. Remember, you used the Mark 14 as a base value to compare with the Type 95 Japanese and you knew both amounts of explosive so you can't use the same percentage increase since the Mark 14 only had 100 as MinEF.

So you need to find out which torpedos had 120 as MinEF and how much explosive that torpedo had to get the % increase. When I looked at the numbers I tried using torpedos that were used about the same time period too, not compare one used in 1930's to 1942 and compare that to one used in 1945.

@Tater and Webster: I understand your ideas. I was discussing with Keltos that the problem we are going to run into is the way the game uses "hitpoints". I think there are way too many varialbes involved to say anything exact. But we did have amounts of explosive in the warhead to compare, taken from documentation we found. Problem came in when we both make simple mistakes. He started with the wrong base value and I was comparing to the Type 96 when I though I was comparing to the Type 95 (I was looking at he wrong zon file) so we ended up with two different sets of numbers, we have corrected that.
But the point I was bringing up about damage, is variables involved. Easier to explain with an example.
Comparing warhead from Mark 14 to Type 95 gave a little over 38% more explosive with the 95. Now you fire the torps at a ship and hit the same spot in the center of a compartment, Mark 14 makes a hole, compartment floods. Take the Japanese torp in same location, Type 95 makes a bigger hole, flood faster. Result in real life, one compartment flooded. Bigger hole but basically same damage. In game: more hitpoints given to the ship.

Example 2: Both torps hit close to a bulkhead. Mark 14 makes a hole, does some damage to the bulkhead but not enough to flood both compartments. type 95 makes a bigger hole, so it either extends the hole to the second compartment or damages the bulkhead enough to flood both compartments. Totally different outcome.

And of couse I am not taking into consideration any cargo or ammo bunkers etc.

So I think the idea of try it 'until it feels right' is a good idea, since there are too many variables for anything to be exact.
Peabody

53.3 cm (21") G7a T1

Ship Class Used On Surface ships and Submarines

Date Of Design about 1930 Date In Service about 1938
Weight 3,369 lbs. (1,528 kg)
Overall Length 23 ft. 7 in. (7.186 m)
Negative Buoyancy 605 lbs. (274 kg)
Explosive Charge (see Notes) 661 lbs. (300 kg) Hexanite
Range / Speed 6,560 yards (6,000 m) / 44 knots
8,750 yards (8,000 m) / 40 knots
15,300 yards (14,000 m) / 30 knots
Power Decahydronaphthalene (Decalin) Wet-Heater

in game :

MinEF=120
MaxEF=180
AP=100
Minradius=3
Maxradius=7

53.3 cm (21") G7e T2 and T3

Ship Class Used On Submarines and Schnellbootes (E-boats)

Date Of Design about 1935 Date In Service about 1939
Weight 3,534 lbs. (1,603 kg)
Overall Length 23 ft. 7 in. (7.186 m)
Negative Buoyancy 597 lbs. (271 kg)
Explosive Charge (see Notes) 661 lbs. (300 kg) Hexanite
Range / Speed Early War: 5,470 yards (5,000 m) / 30 knots
Late War: 8,200 yards (7,500 m) / 30 knots
Power Lead-acid batteries

in game :

MinEF=120
MaxEF=180
AP=100
Minradius=3
Maxradius=7



http://www.navweaps.com/Weapons/WTGER_WWII.htm

the US mk14 has the same values :

MinEF=120
MaxEF=180
AP=100
Minradius=3
Maxradius=7

the german ES torpedo has a slightly lower hitpoint :

MinEF=80
MaxEF=160
AP=100
Minradius=3
Maxradius=7

so the only values that vary here are minEF and maxEF. I'll redo my mod accordingly.

keltos

http://img6.imageshack.us/img6/250/tableztz.jpg


fixed the mistakes in my excell file, the values look better now.

keltos

http://img148.imageshack.us/img148/1815/torpdam.jpg

3 type 89 broadside hits : listing heavily but not sinking yet. Yes this is better :)


corrected mod :

http://files.filefront.com/v+38+IJN+.../fileinfo.html

keltos

I am thinking if you want to calculate power in a better way that you have to add a qualifier based on the the explosive used.

IE: TNT as the base and listed as 1

Japanese TNT with additives to make it more stable increased its power over regular by about 7 percent so list it as 1.07

US Torpex increased explosive power over regular TNT by 50% so list its modifier as 1.5.

Now with those multipliers use your explosive sizes and you might be a step closer in a fair increase for U S torpedo damage.

So in order to qualify the level of TNT for each torpedo

Mark 14: 643 lbs * 1.5 = 964.5 lbs of TNT

Type 95 mod 1 893 lbs * 1.07 = 955.51 lbs of TNT

Which makes the Mark 14 a tiny bit more powerful than the type 95!

Thats me story and I am sticking to it.

Yeah, that is important. In that thread about the german fish, it was surprising, but regardless of the actual amount of explosive in the german fish, the mk14 sank 7k ton ships at a MUCH higher rate with a single hit than german torpedoes in 1944. Like 18% 1 hit sinkings for germans vs 69% for the mk14.

Torpex was a very good explosive, and apparently MUCH better than hexanite based on the stats (I combed all 1944 Liberty ship sinking narratives at uboats.net and compared them to 7k ship sinkings in the PTO for the entire war—confirmed sinkings by japanese records with a specific ship name for each attack, and I went all the way up to 7999tons). The trouble with the mk14 was never the warhead, it was the detonator.

where did you find the data as to the difference between torpex and Type 97 explosive ?

I am not so stubborn that I won't change it again if given new data, but I need facts.

keltos

From my calculation posted above given the facts about torpex in the mk 14 VS japanese type 97 explosives used in the 95.

http://navweaps.com/Weapons/WTJAP_Notes.htm

Under warhead Explosives for japan:

"World War II Torpedoes: The standard explosive charge was 60% TNT and 40% hexanitrodiphenylamine in blocks. This had first been developed by the Germans in 1907 and was very resistant to shock. This explosive was classified as Type 97 by the Japanese and was about 7% more powerful than 100% TNT."

http://www.geocities.com/Pentagon/1592/ustorp3.htm

US torpex:



"Warheads
The second major development, new warheads, involved the switch from TNT to Torpex as the high explosive. Torpex is a mixture rather than a pure chemical compound as TNT is. The components are TNT 41%, RDX (Cyclonite, Hexogen) 41% and aluminum powder 18%8. Torpex is attractive because of the increased explosive energy and higher detonation velocity of RDX as compared to TNT and the prolongation of the pressure wave by the aluminum. On a weight basis, Torpex is conservatively about 50% more effective than TNT as an underwater explosive against ships. Torpex is, however, more sensitive than TNT and RDX was expensive and difficult to make safely. The process of converting to Torpex torpedo warheads (and depth charge loadings) began with an order for 20 million pounds in early 19429. The first Torpex loaded warheads10 followed late the same year. The 640 pounds of Torpex in a Mk.14 warhead was at least the equivalent of 960 pounds of TNT11 almost twice the destructive power of the original Mk.14."
____________________





US torpex:

http://en.wikipedia.org/wiki/Torpex

"Torpex is a secondary explosive 50% more powerful than TNT by weight.[citation needed] Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for 'Torpedo Explosive', having been originally developed for use in torpedoes."


Soo looks like your gonna need two mark 14s instead of one.


PS.

Sorry I have to do these posts in small parts as my computer keeps freezeing due to my stupid USB ports hooked into a wireless adapter.

I'll take it into account and redo the math then. But then I also would need to decrease the Type 89 as it used Type 91 explosive and not Type 97.

thanks for all the info,

Keltos

then early mk14 till the end of 1942 are less powerful, then switch to 1.5 times what they did before, any way to mod that ?


so I should use this formula to figure out how powerful they really were ?

weight of Type 97 / 1.5 (being less powerful than torpex) x 1.07

type 95 mod 1
(405 / 1.5 )* 1.07 = 288.9

288.9 / 292 (mk14) = 0.9893 times the power of the mk14 before : 1.38 times

Type 95 mod 2 and Type 96
(550 / 1.5)* 1.07 = 392.333
392.333 / 292 (mk14) = 1.343 times the power of the mk14 before : 1.88 times


and do the others accordingly ? Peabody what do you think ?
I need to be sure what the mk14 were modded from : early or late war explosive power.

any intel on the german explosive?

we could go from there as they didn't improve theirs.

Keltos

below : a very good read, don't have time to read it all now :


quote Tiornu :

The British developed Torpex in 1942, getting it into service right around the end of the year and sharing it also with the Americans who adopted it in 1943. Torpex is considered 50-100% more powerful than TNT. Japanese Type 97 explosive is considered 7% more powerful than TNT. The various explosives used by the Germans were more powerful than TNT, but I don't have any figures for them

tomas:
The German torpedo warhead was slightly more powerful than an equivalent TNT only warhead, but had a much greater brisance than TNT. Torpex, on the other hand would have yielded approximately 20% more power making a 500 lbs warhead the equivalent yield of a 600-lb TNT warhead. The inclusion of aluminium powder to increase brisance would have given a greater destructive power against standard ship hull structures, though not necessarily having an effect on heavy armour.

Bill Jurens :
Too much is generally made regarding the exact relative strength of explosives used in torpedoes. The amount of damage, though of course not entirely unrelated to explosive strength, can be surprisingly disconnected from this variable. Relative strength in and of itself can be a very difficult thing to pin down in any sort of objective way, or -- more properly -- the relative strength of explosives can vary somewhat depending upon exactly what you are measuring. Both overpressure and total impulse are important, and in some cases, if the charge bubble period is in resonance or near-resonance with the structure, a smaller charge of 'weaker' explosive can actually do more physical damage.

http://www.kbismarck.org/forum/viewt...644fda231667aa

you probably already know this but the game "always" uses the max value and the min value does nothing really but i still keep them in proportion.


AP= <<<< i use this only as an adjustment for small tweaks

Minradius=3 <<<< this value should always stay the same

Maxradius=7 <<<< this value should always stay the same

http://img301.imageshack.us/img301/3033/data1.jpg

http://img15.imageshack.us/img15/3151/data2k.jpg
http://www.fischer-tropsch.org/prima...t%200-01-1.pdf

why don't you change the min and max value ? a kaiten's explosion of its 3400 lbs should make a big damage sphere shouldn't it ? not 7 m..

how exactly do you use the AP factor ?

keltos

list of japanese explosives :
http://en.wikipedia.org/wiki/List_of..._II_explosives