The invasion of Oahu, December 1941.

Discussions on alternate history, including events up to 20 years before today. Hosted by Terry Duncan.
Locked
ChristopherPerrien
Member
Posts: 7051
Joined: 26 Dec 2002, 01:58
Location: Mississippi

Re: The invasion of Oahu, December 1941.

#316

Post by ChristopherPerrien » 16 Oct 2014, 23:12

glenn239 wrote:
ChristopherPerrien wrote: I know. What I meant was Glen's original post and Tinkerbell plan had no mention of wing bombs on Vals, I think. But in the years since then, in debating about IF the VALs could have destroyed the tank farms , the VALs suddenly morphed into automatically having wing bombs in these later debates, here and on other forums.
When considering the hypothetical target of oil tanks, I go with the B5N2 bombing from over 10,000 feet, carrying either 60kg x 6 or 250kg x 2 bomb load.
I see , so you are going to forego attacking any ships, with the only aircraft that really damaged any ships in the first two historical waves, and fly them in nice straight level 10,000 foot bomb runs, for 200-300 operable/alert and ammo ready 5in AA guns firing at a very optimal range and speed for such guns to shoot at -(almost drone training target data). Good luck at that, of course in this ATL, the American were so dang chitty they might shoot down maybe one plane, since they only knocked down 10 or so the day before with far less of them 5 inchers being manned and ammo ready , and shooting primarily very slant closer range low altitude targets. Wait I forgot about all the magic smoke which blocks these guns from being able to see any aircraft, yet doesn't hinder these Kates at all, I seem to recall that gem from some prior discussion.

Oh yea, and 125 planes(none shot down of course) get 42 point target hits. What is that 35%+ bombing accuracy ? Why aren't air-forces and navies of today not flying Kates since they seem to be more accurate than today's jets with PGW's and LGW's ? Oh wait , we must need those mythic Japanese carrier bomber pilots that all mysteriously disappeared in 1942-43. :D

If you wish to say something about multiple bombs from one aircraft somehow equating to an extra target destruction chance per bomb, well I guess I can say my old M1 tank was equivalent to 63 tanks since it carried 63 main gun rounds :milsmile: LOL. In truth my tank was only equivalent to 14 tanks , However that is another GREAT story :thumbsup: but it won't work for IJN Kates of WWII or most bomber air-craft of any era.

Excuse the sarcasm, kinda unavoidable when it comes to 3rd wave/cake-walk invasion for Hi. in Dec1941.

User avatar
phylo_roadking
Member
Posts: 17488
Joined: 01 May 2006, 00:31
Location: Belfast

Re: The invasion of Oahu, December 1941.

#317

Post by phylo_roadking » 17 Oct 2014, 00:04

On an associated note...
Wait I forgot about all the magic smoke which blocks these guns from being able to see any aircraft, yet doesn't hinder these Kates at all, I seem to recall that gem from some prior discussion.
...had the Americans adopted the "box barrage" tactic yet? Which would of course have negated the effect of any smoke around...
Twenty years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs....
Lord, please keep Kevin Bacon alive...


ChristopherPerrien
Member
Posts: 7051
Joined: 26 Dec 2002, 01:58
Location: Mississippi

Re: The invasion of Oahu, December 1941.

#318

Post by ChristopherPerrien » 17 Oct 2014, 00:20

phylo_roadking wrote:On an associated note...
Wait I forgot about all the magic smoke which blocks these guns from being able to see any aircraft, yet doesn't hinder these Kates at all, I seem to recall that gem from some prior discussion.
...had the Americans adopted the "box barrage" tactic yet? Which would of course have negated the effect of any smoke around...
Such tactic seems to be attached to fixed AA defenses dealing with a known repetitive threat. Would be very difficult to set up with movable AA assets that constantly keep changing by berthing status of so many ships. Even berthed , ships will be off a few degrees from prior berthings, tides? , and not being in the exact same spot.

My earlier post was only dealing with operable ship mounted 5inch AA guns, about 40 ships mounting 4-8 each, plus odd ball auxiliaries, etc. No idea on fixed 5 inch or 76mm AA ship or fixed , or other capable heavy AA guns. Or if the fixed AA guns of Pearl had some "box barrage" plan, I don't there were enough to do so and/as the area to be defended was larger than historic examples of Malta and Corregidor.
Last edited by ChristopherPerrien on 17 Oct 2014, 00:34, edited 1 time in total.

User avatar
phylo_roadking
Member
Posts: 17488
Joined: 01 May 2006, 00:31
Location: Belfast

Re: The invasion of Oahu, December 1941.

#319

Post by phylo_roadking » 17 Oct 2014, 00:28

Such tactic seems to be attached to fixed AA defenses dealing with a known repetitive threat. Would be very difficult to set up with movable AA assets that constantly keep changing by berthing status of so many ships. Even berthed , ships will be off a few degrees from prior berthings, tides? , and not being in the exact same spot.
Well, that's what we're talking about in respect of the fuel tankage ;) Fixed AA defences around a very static target...

Although, to be fair, through 1941 the British were managing to do it over shipping in Valetta, shifting the "box" as necessary ;) They were able to move it to cover the Illustrious, for example...

And at a guess Malta was a lot shorter on AA and AA munitions than Pearl was; the limited amount of ordnance available kept firing restircted to a minimum on Malta.

The point about a "box barrage" is - you don't actually need to see or aim at a target - just set your particular gun on the bearing and elevation dictated by the gun control room, and keep feeding it brass fused for the required altitude until you're ordered to stop.
Twenty years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs....
Lord, please keep Kevin Bacon alive...

ChristopherPerrien
Member
Posts: 7051
Joined: 26 Dec 2002, 01:58
Location: Mississippi

Re: The invasion of Oahu, December 1941.

#320

Post by ChristopherPerrien » 17 Oct 2014, 00:46

Opie will eventually show up to answer your question. I don't think they did, but OP will know for certain.

OpanaPointer
Financial supporter
Posts: 5644
Joined: 16 May 2010, 15:12
Location: United States of America

Re: The invasion of Oahu, December 1941.

#321

Post by OpanaPointer » 17 Oct 2014, 01:24

I'm not aware of the USN using a box barrage at the time. We were into directed AA.
Come visit our sites:
hyperwarHyperwar
World War II Resources

Bellum se ipsum alet, mostly Doritos.

ChristopherPerrien
Member
Posts: 7051
Joined: 26 Dec 2002, 01:58
Location: Mississippi

Re: The invasion of Oahu, December 1941.

#322

Post by ChristopherPerrien » 17 Oct 2014, 01:46

Hell , does it matter? On Dec8, the baddest warship to ever sail any sea in history was parked in Pearl Harbor. The USS Enterprise, CV-6, which has a forever unreachable battle record of 71 ships sunk , 192 more damaged or sunk, and 911 enemy planes shot down in WWII. And some people think the Japanese would have wiped out everything on Dec 8 with a 3rd wave. PAH !!! Care to dismiss CV-6. when the Japanese themselves later called her the Grey Ghost because they could not sink her, you might upset the dead, both Japanese and American. Needless to add how extremely mad every American soldier and sailor in Hi. and every American elsewhere was on DEC 8. Yea, the Japanese needed to come back on Dec. 8, maybe it would have gained them a few more Hiroshimas and Nagasaki's, just to prove the point Pearl Harbor was a bad idea.

Box -barrage? LOL Go drink some tea before Singapore falls.


^
5 beer post for funsies , no need to reply, just extemporaneous musings

glenn239
Member
Posts: 5862
Joined: 29 Apr 2005, 02:20
Location: Ontario, Canada

Re: The invasion of Oahu, December 1941.

#323

Post by glenn239 » 17 Oct 2014, 18:57

ChristopherPerrien wrote:
I see , so you are going to forego attacking any ships, with the only aircraft that really damaged any ships in the first two historical waves, and fly them in nice straight level 10,000 foot bomb runs, for 200-300 operable/alert and ammo ready 5in AA guns firing at a very optimal range and speed for such guns to shoot at -(almost drone training target data).
Op made no mention of oil tanks being targeted in the first waves. Primary targets were airfields, then battleships, with possible attack on Schofield Barracks by second wave if airfields already crippled. Follow-up waves is when tanks might be targeted, but since detection of Enterprise was likely had Nagumo searched to 300nm on the morning of the 7th, then a naval battle may have developed instead.
Good luck at that, of course in this ATL, the American were so dang chitty they might shoot down maybe one plane, since they only knocked down 10 or so the day before with far less of them 5 inchers being manned and ammo ready , and shooting primarily very slant closer range low altitude targets. Wait I forgot about all the magic smoke which blocks these guns from being able to see any aircraft, yet doesn't hinder these Kates at all, I seem to recall that gem from some prior discussion.
Despite heavy fire, AAA defences at Pearl Harbor scored 0 kills against 104 aircraft attacking at medium altitude.
If you wish to say something about multiple bombs from one aircraft somehow equating to an extra target destruction chance per bomb...
I recall vaguely when looking at the oil tank problem that I did not consider it certain a 60kg bomb could detonate a tank even with a direct hit. I then recall trying to guess what the radius for a 250kg bomb would be. This is a useful picture here,

http://upload.wikimedia.org/wikipedia/c ... lomons.jpg

Showing a 250kg instantaneous fuse bomb at the moment of explosion. It's tough to get an exact handle on how wide that fragmentation pattern is, but I think it is about 50', which suggests if anything the 20' assumption might be too conservative.

OpanaPointer
Financial supporter
Posts: 5644
Joined: 16 May 2010, 15:12
Location: United States of America

Re: The invasion of Oahu, December 1941.

#324

Post by OpanaPointer » 17 Oct 2014, 19:50

We'd know to know the minimum radius of the fragments that would penetrate the walls of the tanks as well. .75" at the top and 1.5" at the bottom.
Come visit our sites:
hyperwarHyperwar
World War II Resources

Bellum se ipsum alet, mostly Doritos.

User avatar
phylo_roadking
Member
Posts: 17488
Joined: 01 May 2006, 00:31
Location: Belfast

Re: The invasion of Oahu, December 1941.

#325

Post by phylo_roadking » 17 Oct 2014, 20:58

It's also quite difficult for a bomb fragment or even a nice red hot speeding bullet to ignite a tankful of petrol, let alone any other POL with a higher flashpoint....or else aircraft fuel tanks wouldn't benefit much from being self-sealing! :P

Unless you're ALSO going to now posit dropping incendiaries from quite low level to be accurate once you somehow get to know that tanks have been punctured...

...the real risk is in fact from petrol vapour...which is more highly flammable than the actual liquid. And wouldn't be down around the bottom of tanks anyway where bomb fragments would be bouncing off them...
Twenty years ago we had Johnny Cash, Bob Hope and Steve Jobs. Now we have no Cash, no Hope and no Jobs....
Lord, please keep Kevin Bacon alive...

OpanaPointer
Financial supporter
Posts: 5644
Joined: 16 May 2010, 15:12
Location: United States of America

Re: The invasion of Oahu, December 1941.

#326

Post by OpanaPointer » 18 Oct 2014, 04:12

phylo_roadking wrote:It's also quite difficult for a bomb fragment or even a nice red hot speeding bullet to ignite a tankful of petrol, let alone any other POL with a higher flashpoint....or else aircraft fuel tanks wouldn't benefit much from being self-sealing! :P

Unless you're ALSO going to now posit dropping incendiaries from quite low level to be accurate once you somehow get to know that tanks have been punctured...

...the real risk is in fact from petrol vapour...which is more highly flammable than the actual liquid. And wouldn't be down around the bottom of tanks anyway where bomb fragments would be bouncing off them...
The vapor is the part that actually burns.

Fifty-four tanks, ~15% accuracy with the dive bombers, 8 tanks hit, no real chance of sitting anything on fire. Hardly crippling.
Come visit our sites:
hyperwarHyperwar
World War II Resources

Bellum se ipsum alet, mostly Doritos.

Carl Schwamberger
Host - Allied sections
Posts: 10056
Joined: 02 Sep 2006, 21:31
Location: USA

Re: The invasion of Oahu, December 1941.

#327

Post by Carl Schwamberger » 18 Oct 2014, 04:25

OpanaPointer wrote:We'd know to know the minimum radius of the fragments that would penetrate the walls of the tanks as well. .75" at the top and 1.5" at the bottom.
There are various data for that held by many armies, air forces, and navys. No I dont have any, I dont know if the documents I used have been declassified, & I wont post my personal observations of frags on targets now. Maybe if something turns up in a search I'll get back with it.

I will preset two related items; A. test by the US artillery in the 1920s found that overcharging the projectile with explosive produced fragmentation amounting to 'hot sand' and undercharging produced large fragments with little velocity & effective impact. The proper ratio of exploisive to casing resistance/fragmentation characteristics was fairly narrow.

B. How efficient had the Japanese been in designing to that ratio for their aircraft bombs? I've run across two claims that 1. aircraft bombs & 2. Naval cannon projectiles were overcharged with explosive & had the hot sand syndrome. Perhaps those remarks were based on specific situations or otherwise dont apply here, perhaps they do. I'll have to dig them out for review.

glenn239
Member
Posts: 5862
Joined: 29 Apr 2005, 02:20
Location: Ontario, Canada

Re: The invasion of Oahu, December 1941.

#328

Post by glenn239 » 18 Oct 2014, 15:14

Not sure on bombs, but if anything I'd guess IJN HE shells would be undercharged, judging from explosive weight to shell weight on Navweapons.

ChristopherPerrien
Member
Posts: 7051
Joined: 26 Dec 2002, 01:58
Location: Mississippi

Re: The invasion of Oahu, December 1941.

#329

Post by ChristopherPerrien » 18 Oct 2014, 16:25

phylo_roadking wrote:It's also quite difficult for a bomb fragment or even a nice red hot speeding bullet to ignite a tankful of petrol, let alone any other POL with a higher flashpoint....or else aircraft fuel tanks wouldn't benefit much from being self-sealing! :PUnless you're ALSO going to now posit dropping incendiaries from quite low level to be accurate once you somehow get to know that tanks have been punctured......the real risk is in fact from petrol vapour...which is more highly flammable than the actual liquid. And wouldn't be down around the bottom of tanks anyway where bomb fragments would be bouncing off them...
Well we are not talking about pure petrol (sp-gasoline) vapors here , we are talking #5 bunker oil and bunker C, about the only vapors from them were from whatever partial evaporation from distillates that were added so they so they flowed better than "tar".
Probably can't really call them fumes, more like a "smell" as far as any combustible concentration or flash goes.

OpanaPointer
Financial supporter
Posts: 5644
Joined: 16 May 2010, 15:12
Location: United States of America

Re: The invasion of Oahu, December 1941.

#330

Post by OpanaPointer » 18 Oct 2014, 17:17

ChristopherPerrien wrote:
phylo_roadking wrote:It's also quite difficult for a bomb fragment or even a nice red hot speeding bullet to ignite a tankful of petrol, let alone any other POL with a higher flashpoint....or else aircraft fuel tanks wouldn't benefit much from being self-sealing! :PUnless you're ALSO going to now posit dropping incendiaries from quite low level to be accurate once you somehow get to know that tanks have been punctured......the real risk is in fact from petrol vapour...which is more highly flammable than the actual liquid. And wouldn't be down around the bottom of tanks anyway where bomb fragments would be bouncing off them...
Well we are not talking about pure petrol (sp-gasoline) vapors here , we are talking #5 bunker oil and bunker C, about the only vapors from them were from whatever partial evaporation from distillates that were added so they so they flowed better than "tar".
Probably can't really call them fumes, more like a "smell" as far as any combustible concentration or flash goes.
The stuff had to be heated before a spray could be ignited. Napalm would have had work to ignite that stuff. Rupturing the tanks wouldn't have destroyed the fuel, it would have pooled in the berms and s*l*o*w*l*y seeped into the ground.

Additional problem for the IJN, which tanks were full, which were empty?
Come visit our sites:
hyperwarHyperwar
World War II Resources

Bellum se ipsum alet, mostly Doritos.

Locked

Return to “What if”