Models of Naval Combat

[herwin]

Just a few points from some old operations research studies:

1. WWII air-to-air combat results were sensitive to (most of all) pilot quality and the aircraft characteristics. The most important aircraft characteristic was top speed. Numbers were interesting--the rate of engagement was proportional to the number of aircraft in the smaller force, but beyond that, the exchange ratio was fixed by pilot quality and aircraft characteristics. There was no advantage to numbers.

2. Fighter versus bomber combat was again an exchange ratio process. The main factor was relative firepower.

3. Ship resistance to sinking was proportional to waterline area. Armor and underwater protection reduced the effect of damage--the waterline area destroyed by a hit. This meant that (ignoring protection) the resistance of a CA to sinking was about half the resistance of a modern BB. Carriers were about 2/3rds as resistant to sinking as a comparable sized gunship.

4. Bomb and gunnery damage were proportional to the 2/3rds power of the bursting charge for penetrating hits (in other words the waterline area affected by the blast). When sustained rate of fire was considered, this implied a modern CA was about half as damaging as a modern BB. Given that the cost of the CA was markedly less than that of a BB, why build BBs? Answer: armor protection.

5. Torpedoes used a different mechanism for sinking ships--opening a length of the ship to the sea. The length was proportional to the 1/3rd power of the warhead size, but torpedos were very lethal. One would take out a DD about half the time; 2 was sufficient. Cruisers and battleships were a bit more resistant. Figure one American aerial torpedo per 200 feet of length to get a reliable kill of a gunship. More like one torpedo per 300 feet for a carrier. Note that burnouts and critical damage were also possible.

6. Hit probability varied. Dive bombers and Japanese G3M/G4Ms would get a hit about two times in nine on a maneuvering target. American torpedo aircraft were about half as effective. An American deck-load strike was good for about 8 bomb hits and 2 torpedo hits if everyone made an undisturbed drop. A Japanese CV would get 4-6 bomb hits and about 4 torpedo hits.

My notes on this are stashed away, but I can probably find them if there's further interest.

[Iridium]

The latter on CV durability is interesting. Since US CVs had armored decks this makes sense, however the Japanese CVs taking more torpedos isn't making much sense to me at the moment. Perhaps if this is all based on actual battle damage then the sheer overkill of Japanese ships at the end of the war causes these figures.

One could take the number of bomb and torpedo hits to both Yamato class boats and it would lopside any other figures in terms of durability of BBs made by that nation.

Just a few thoughts...

[hawker]

The latter on CV durability is interesting. Since US CVs had armored decks this makes sense, however the Japanese CVs taking more torpedos isn't making much sense to me at the moment. Perhaps if this is all based on actual battle damage then the sheer overkill of Japanese ships at the end of the war causes these figures.

One could take the number of bomb and torpedo hits to both Yamato class boats and it would lopside any other figures in terms of durability.

Just a few thoughts...

US CVs doesnt have armored decks,Brittish CVs has armored decks[;)]

[Iridium]

Oh yeah...well then what the hell?[:D]

[Nikademus]

US CV's had an armor deck. UK CV's had an armored flight deck

[hawker]

US CV's had an armor deck. UK CV's had an armored flight deck

I WAS thinking on flight deck Nik[;)].

[Nikademus]

my pyschic powers are on the fritz today. so pulling your intent out of the words was unsuccessful. Regrettably, my attempt to guess the latest winning Lotto combination also proved futile...oh well....all you need is a $1....a dream and a chance to get hit by an airplane wing.

[Terminus]

Don't forget a cat to punt...

[Feinder]

As I read the CV comparison, it means "hits on the enemy". As in full strike by an American CV was good for about 8 bombs and 2 torpedos against the enemy. A strike by a Japanese CV was good for about 4 - 6 bombs and 4 torpedos. Thus American DBs were likely more effective against their opponenets, wherease Japanese TBs were more effective.

Interesting. Not questioning, but yes, I'd be intereested to see the documentation for the statistics. I know there was a LOT of statistical analysis done after the war, there is quite a bit of documentation available.

Interesting.
-F-

[Iridium]

ORIGINAL: Feinder

As I read the CV comparison, it means "hits on the enemy".

Ah, must have missed that meaning. Yeah the torpedo planes of Japan probably did have better hit ratios.

[Nikademus]

very true!

[Big B]

ORIGINAL: Feinder

As I read the CV comparison, it means "hits on the enemy". As in full strike by an American CV was good for about 8 bombs and 2 torpedos against the enemy. A strike by a Japanese CV was good for about 4 - 6 bombs and 4 torpedos. Thus American DBs were likely more effective against their opponenets, wherease Japanese TBs were more effective.

Interesting. Not questioning, but yes, I'd be intereested to see the documentation for the statistics. I know there was a LOT of statistical analysis done after the war, there is quite a bit of documentation available.

Interesting.
-F-

What he said...

[TheElf]

I'm still waiting for the imminent beat down of Herwin's post by some of the local Forum thugs....(Where's that damn devil with the popcorn?)

[scott64]

[pompack]

Harry: Great post

I would be interested in the background data as well. Do you have online references or can the data summeries be posted?

Also, the folks working on BTR may very well be able to gain some insight from the old studies.

[Mike Scholl]

ORIGINAL: herwin

Just a few points from some old operations research studies:

1. WWII air-to-air combat results were sensitive to (most of all) pilot quality and the aircraft characteristics. The most important aircraft characteristic was top speed. Numbers were interesting--the rate of engagement was proportional to the number of aircraft in the smaller force, but beyond that, the exchange ratio was fixed by pilot quality and aircraft characteristics. There was no advantage to numbers.

2. Fighter versus bomber combat was again an exchange ratio process. The main factor was relative firepower.

3. Ship resistance to sinking was proportional to waterline area. Armor and underwater protection reduced the effect of damage--the waterline area destroyed by a hit. This meant that (ignoring protection) the resistance of a CA to sinking was about half the resistance of a modern BB. Carriers were about 2/3rds as resistant to sinking as a comparable sized gunship.

4. Bomb and gunnery damage were proportional to the 2/3rds power of the bursting charge for penetrating hits (in other words the waterline area affected by the blast). When sustained rate of fire was considered, this implied a modern CA was about half as damaging as a modern BB. Given that the cost of the CA was markedly less than that of a BB, why build BBs? Answer: armor protection.

5. Torpedoes used a different mechanism for sinking ships--opening a length of the ship to the sea. The length was proportional to the 1/3rd power of the warhead size, but torpedos were very lethal. One would take out a DD about half the time; 2 was sufficient. Cruisers and battleships were a bit more resistant. Figure one American aerial torpedo per 200 feet of length to get a reliable kill of a gunship. More like one torpedo per 300 feet for a carrier. Note that burnouts and critical damage were also possible.

6. Hit probability varied. Dive bombers and Japanese G3M/G4Ms would get a hit about two times in nine on a maneuvering target. American torpedo aircraft were about half as effective. An American deck-load strike was good for about 8 bomb hits and 2 torpedo hits if everyone made an undisturbed drop. A Japanese CV would get 4-6 bomb hits and about 4 torpedo hits.

My notes on this are stashed away, but I can probably find them if there's further interest.

PLEASE provide the "notes and references" on which this is based. It sounds reasonably accurate for 1942 but not for later periods of the war. The Japanese Val pilots at the beginning of the war were outstandingly effective in getting hits (and needed to be with their relatively small bomb loads)---but as Allied flak and CAP increased these guys got hammered and replacements of that quality couldn't be found. The same could be said of the Kate or Nell or Betty pilots. All of them pressed home attacks to what became almost suicidal ranges and got more hits per try than the Allies---and as the defense improved the suicidal portion of the equasion came to the foreground and the lack of replacements caught up with them. And as Turner proved off Guadalcanal, there were defensive tactics that could reduce the threat considerably. In the later war the Allied "mass" of "good enough" overwhelmed the Japanese emphasis of "perfect".

[herwin]

A few points--CVs were *less* durable than gunships built on the same hulls. Probability of a burnout per hit depended on nationality and design. There were two or three Essex class CVs that were burned out. They weren't sunk, but they weren't worth repairing.

The divebomber hit statistics were comparable between the two navies, but US CVs had more dive bombers and less torpedo bombers.

The background data were open source, but some of it was Soviet and some was declassified German-language material that I translated for Nathan Okun. I basically developed a database of every ship damage report available at the time. I did similar work with aircraft losses. The analysis was mostly mine and was used in some unpublished studies. I moved on to other work about 1979.

[el cid again]

1. WWII air-to-air combat results were sensitive to (most of all) pilot quality and the aircraft characteristics. The most important aircraft characteristic was top speed. Numbers were interesting--the rate of engagement was proportional to the number of aircraft in the smaller force, but beyond that, the exchange ratio was fixed by pilot quality and aircraft characteristics. There was no advantage to numbers.

This may be false. A WWI era British aviator came up with an algorithm that says numbers matter more than you would expect. This algorithm appears to be valid into the Cold War era. I am very suspicios of a stated finding at variance with many studies over many decades.

[el cid again]

2. Fighter versus bomber combat was again an exchange ratio process. The main factor was relative firepower.

This must mean an actual air battle. Something critical is missing here: the statement must be qualified by the following principle:

The victor in air air combat USUALLY is NOT DETECTED by the victim.
This is a 90% case. In air combat where both sides know it is air combat, it is almost always possible to escape UNLESS YOU DO NOT WANT TO.
Only 10% of air combat losses involve enemies that knew they were in an air battle. ONLY if the "exchange ratio" statements is limited to that 10% is it valid.

I bet the writer of the principle does not understand air combat. I bet they are looking at sortee rates, loss rates, etc and ASSUMING they know what happened, without looking at data for each sortee.

[Kadrin]

ORIGINAL: herwin

There were two or three Essex class CVs that were burned out. They weren't sunk, but they weren't worth repairing.

Just out of curiosity, which Essex class CV's were those? I have a book here that lists all of them and their fate. All of carriers that were built were in service into the 50's when they started converting them into CVA's and CVS's (even a few AVT's and LPH's) where they continued to serve (minus: Bunker Hill scrapped in 66, Franklin also scrapped in 66, Lake Champlain scrapped in 69, Tarawa scrapped in 68 and Philippine Sea scrapped in 69). The Book stops at 1970.

I'm wondering if those burned out just sat around til the 50's and then were converted?