Dec.7'41: A Day That Nobody Bombed Panama !

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#271

Post by phylo_roadking » 01 Feb 2009, 00:16

So transit across Gatun lake is still possible for anything EXCEPT battleships while the water is still goING down...and restarts when the water is replenishING.

Meanwhile, there IS still water in Gatun lake to operate the Gatun locks...

Therefore the transit of the USN's capital ships from Atlantic to Pacific is just inhibited for that narrow window when the water level is RIGHT down at the gate sills.

That could be for as little as a few days. Even a few extra feet of water in that lake from that "minimum" allows them to transit, once "de-oiled" and using tugs, once replenishment begins.
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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#272

Post by phylo_roadking » 01 Feb 2009, 00:20

Simon, in reference to your nets....

Robert's source http://www.ibiblio.org/hyperwar/USN/Bui ... es-18.html says on Page 15
By the end of 1940, work had begun on a new supply depot at Balboa, and on the Farfan Radio Station on the west bank, together with the enlargement of the two inland radio stations at Gatun and Summit. Two net depots were started in December, one at each end of the Canal, and during the same month a third contract was awarded for 1,400 housing units, 1,100 at Coco Solo and the remainder on the west bank at Balboa. The following summer two naval hospitals, one at Coco Solo and the other at Balboa, were begun.
If that isn't a simple misprint - then looks to me as if there's going to be plenty of anti-torpedo netting around!!!


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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#273

Post by Simon K » 01 Feb 2009, 00:43

Game over. Rob it aint a goer.

Now I am going to my heavily defended bed.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#274

Post by robdab » 01 Feb 2009, 00:45

glenn239,

What I want to know is, dropping all operational requirements and logistic assumptions from the equation, what is required to knock the Panama Canal out of operation for 3 months, in terms of amount of explosive delivered where ?

I have been working on that very question since Bill pointed out my error with the Madden Dam source but I am coming to the conclusion that it is not possible to knock out the Canal for just 3 months, save for a big rockslide at the Cut. Explosives drilled into the flanks of those unstable slopes and set off in the rainy season MIGHT trigger a slide big enough, but then, might not. There was constant dredge work going on there though so the Americans already had the equipment and people in place to begin clearance on the same day.

The Canal's design seems to be bulletproof enough that only draining Gatun Lake almost dry will do the trick. That would require either overtopping or breaching the Gatun Dam or one of the other earthen dykes that were built to create that Lake. However, those were all built to resist just such erosive destruction.

I suspect that it would take much explosive, carefully installed, to answer your question.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#275

Post by phylo_roadking » 01 Feb 2009, 00:49

Explosives drilled into the flanks of those unstable slopes and set off in the rainy season MIGHT trigger a slide big enough, but then, might not.
Problem is - explosive can ALSO be used to disperse the slide for easier removal, turn it into a simple dredging problem. Remember the number of Army and Navy construction workers available in December 1941...
it would take much explosive, carefully installed
Two factors that are NOT going to come together unhindered.
That would require either overtopping
Why do you assume it would be possible to damage the dam by overtopping it? The spillways were to regulate the height of the water and prevent flooding of the lakesides i.e. to BALANCE these two requirements; today the dam runs right up at the 87' level, the TOP of the gates, not two feet below as was the norm in the 1940s; the gates are used to move away water, but IF OVERTOPPED that just means ALL the spillways feed from whatever goes over the TOP of ALL the gates. Nowhere have I seen any reference to any concerns that the water level overtopping ALL the CLOSED dam gates does anything except fears of causing flooding in Gatun TOWN etc. along the shore of the LAKE. Even today the higher water level isn't doing much except drown old USN installations around the lakeshore and give worries about the gates because they're now so dam (sic) OLD. Hence the plans for a second LARGER spillway...

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#276

Post by robdab » 01 Feb 2009, 01:06

phylo_roadking,

Readers can take a look at http://www.globalsecurity.org/military/ ... -schem.htm and see the REAL two-line illustration of the Mizuho....yes you can remove the central platform - or rather take the Chitose into port and spend months rebuilding her elevator....BUT YOU CAN'T REMOVE THE TOWERS. So while you may actually fit a third Mavis aboard...it can only be loaded by a shore crane and it's STILL STUCK BETWEEN THE ELEVATOR TOWERS, with no way for the crane at the rear to lift it out from between them!!! :lol: :lol: :lol:

I believe that if you were to read my initial thread starting post you would see that I suggested installing a large heavy duty flyingboat capable crane on my ATL Chitose, similar to that seen on the Akitsushima, just behind that central platform. Thus, a third Mavis could be lifted out from between the columns and launched over the side. The much lighter duty original equipment stern crane would not be needed for that task at all.

Please try to keep up.


If you guys are going to keep posting at this rate then I'm never going to catch up !

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#277

Post by phylo_roadking » 01 Feb 2009, 02:04

Robert, I believe if you do some better investigation into maritime crane types. A crane of that type with it's fixed jib would have a minor problem hoisting ANYTHING out from between the elevator towers...as it rotates from hoisting the other two off the afterdeck into the sea - it go CLANG! AGAINST the rear elevator tower!!! :lol: :lol: :lol:

And if you make it tall enough to reach OVER the tower - apart from the Chitose rolling over because despite how you ballast her you've made the ship disastrously top-heavy - the FIXED jib is TOO long...

bugger it, where's my pen...

Image

as I said....CLANG!

And remember - it's a fixed ladder jib...

Image

I'm not sure it can actually be raised further than shown on the Akitsushima two-line drawing; even if it CAN, is there THEN enough space in the engle that a Mavis can be hoisted far enough up to clear the towers without hitting the jib itself??? Because I'll just bet...

...YOU HAVEN'T MEASURED THE GAP BETWEEN THE ELEVATOR TOWERS :wink:

23.7 metres...and an H6K is - as I said before - 25.63m long, with a wingspan of FORTY metres...there's no way you can jiggle it around to fit BOTH those parameters into that space...

IT DOESN'T FIT ANYWAY 8O

As I said....TWO Mavis'...at a pinch.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#278

Post by phylo_roadking » 01 Feb 2009, 03:11

Playing with a couple of scaled printouts of three-line drawing of H6Ks produces THIS -

Image

....but there's STILL no way of getting the third in between the elevator towers without loosing about half the tail.

It's going to be TWO (2) only in the attack force.

(ANOTHER tiny little problem is the trim of the Chitose with this load on her afterdeck. Two H6k Mavises - even empty - STILL weighs in at TWENTY-THREE TONS...and you have to admit, that DEFINITELY has to be described as "above the waterline" :lol: :lol: :lol: Her sea manners could be severely compromised by that, and the huge amount of ballasting she's going to have to carry in an attempt to re-trim. I note that of the few pictures I've found of the Chitose under way, she has her seaplane complement as far forward as possbile...impossible with the H6Ks.)
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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#279

Post by phylo_roadking » 01 Feb 2009, 05:04

One other minor problem about the Chitose....

Exactly what is under her deck where you want the IJN to convert her to an Akitsushima-type crane??? :wink:

The Chitose class, built as "shadow" vessels for Washington Treaty-busting for a possible later conversion to a full-deck carrier had a LOT more than just elevator pits and their foundation assemblies down there, they had spaces braced and bulkheaded as magazines, and for aviation fuel stowage...

It might be worth doing some more in-depth research on the Chitose and finding out if she COULD even have had such a crane mounted and counterweighted in your central location... :wink:

P.S. WHEN do you expect the IJN to carry out this crane conversion?

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#280

Post by robdab » 01 Feb 2009, 08:38

phylo_roadking,

- they don't need to be recognized as foreign[/i] They JUST need to be any aircraft spotted where they're not supposed to be, or not be where any Pan-Am or Panagras aircraft should be...to immediately raise questions. You don't seem to realise how fail-deadly the flight and airspace regulations for the Canal Zone and later the rest of Panama was; ALL aircraft had to fly along specific corridors since 1939 AND we have proof of that actually happening - American AND foreign - while NON-American planes were subject to interception and inspection...this policy later extending to the rest of Panama after December 1940 and the establishment of the Joint Air Board. Because Pan-Am and Panagras flights in and out of Panama had flight plans logged with the Army the locations of ALL their flights were known in advance, and any strays would be investigated on detection or report. EVEN PAN-AM OR PANAGRAS AIRCRAFT WOULD BE INTERCEPTED AND INVESTIGATED IF THEY STRAYED OUTSIDE THE AIR CORRIDORS OR WERE REPORTED WHERE THEY WEREN'T SUPPOSED TO BE.

Your evasion plan doesn''t actually have any way around the level of regulation the Army had over traffic in and out of Panama from 1939 on. They knew what WAS supposed to be where - and anything that was anywhere else was liable to pursuit and interception. It's a pretty clear either/or.

I presume you haven't yet sourced a copy of AAFHS-42. When you do you'll be suprised at the sheer number of flying hours being flown by Army Air Force pilots in the Cana Zone; tens of thousands of hours a month, on live exercising and training, Army cooperation with AA training (target-towing), bombardment training at the bombing and ground target ranges at Rio Hato, flying to test and train the AWS, transport flights by B-18s...unsuitable or not...to transport men and material around the dozens of auxiliary landing fields - together with the very frequent good-will Air Tours around other Central American nations. So MUCH so that for a couple of months in early 1941 (emphasis on early; the problem began to vanish in May 1941 with the rapid influx starting then of new aircraft and spares) that engine rebuilds due to flying hours was for that short window making aircraft availability very questionable...

In other words - with the Canal Zone AF command being one of the busiest in the service outside the GHQ area despite the dated and cr@ppy aircraft they had, there is EVERY chance that if the weather over the Canal was fine enough for your putative attackers to depart the Chitose on their mission, there would be dozens of USAAF aircraft actually in the air over the Canal Zone and Panama!!! 8O

So not only is the airspace your attackers intend to linger in covered by a network of regulation specifically to prevent stray unidentified aircraft...there will be a LOT of prying eyes around, in the air not just on the ground :lol:


You paint a devastating picture of the just pre-war American air defenses of Panama but I fear 'tis all in your imagination. All that regulation, radar and all of those eyes in the air and on the ground ... WOW !

Please tell me then, how it is that you explain the now WARTIME March 1942 revalation by American Secretary of War Stimson that planes on a recent exercise had not been spotted until they were within 15 miles of the Canal ? From page #304 of http://books.google.ca/books?id=EuE7Jzq ... #PPA304,M1

The details of that test exercise are not revealled but we do know that they weren't dealing with a case of peacetime surprise attack and I'd bet that the test's "enemy warplanes wer not disguised as "China Clippers". 15 miles away.

That same page also points out that the radar of the day could NOT pick-up low flying aircraft at all, which is just the height that my 3 ATL Mavis would have been headed for in order to drop their torpedoes.

I know that a Mavis is not the fastest warplane on the planet but one can cover 15 miles in just less than 5 minutes at it's attack speed of 184 knots. Little time at all for the American fighters to find them, with no radar vector, when they were flying "down in the weeds" on the last leg of their attack. That twin 20mm "tail stinger" could be nasty.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#281

Post by robdab » 01 Feb 2009, 08:47

phylo_roadking,

...but there's STILL no way of getting the third in between the elevator towers without loosing about half the tail.. -I have no intention of taking this ATL Chitose conversion discussion down to the level of how many paint brushes would be required. Since the IJN had sufficient qualified marine designers on staff to design the Chitose in the first place, I don't think it improbable to believe that those designers could have re-designed her to carry 3 Mavis as deck cargo.

(ANOTHER tiny little problem is the trim of the Chitose with this load on her afterdeck. Two H6k Mavises - even empty - STILL weighs in at TWENTY-THREE TONS...and you have to admit, that DEFINITELY has to be described as "above the waterline" :lol: :lol: :lol: Her sea manners could be severely compromised by that, and the huge amount of ballasting she's going to have to carry in an attempt to re-trim. I note that of the few pictures I've found of the Chitose under way, she has her seaplane complement as far forward as possbile...impossible with the H6Ks.)[/quote] - the previous source that I posted here lists the Mavis's empty weight at 12,025 kg or about 13 tons each, not 23 tons each.

Please try to keep up.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#282

Post by moab76 » 01 Feb 2009, 16:40

Ok Rob, you've come up with all these improbable things as to what you think they could have done. Now, have you done any analysis of WHY they didn't do them? That is a pertinant question.

Just maybe, they saw things you don't see.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#283

Post by phylo_roadking » 01 Feb 2009, 17:23

Please tell me then, how it is that you explain the now WARTIME March 1942 revalation by American Secretary of War Stimson that planes on a recent exercise had not been spotted until they were within 15 miles of the Canal ? From page #304 of http://books.google.ca/books?id=EuE7Jzq ... #PPA304,M1
When you began this discussion you were adamant your aircraft could penetrate all the way in to Gatun without being spotted AT ALL by ANYONE. Now you're reduced to finding data that show that on exercise intruder aircraft were spotted FIFTEEN MILES from the Canal. That is NOT the most impressive datum to present in support of your argument!!! :lol: :lol: :lol: Fifteen miles is more than enough for patrolling P-40s to splash two Mavis flyingboats.
The details of that test exercise are not revealled but we do know that they weren't dealing with a case of peacetime surprise attack and I'd bet that the test's "enemy warplanes wer not disguised as "China Clippers". 15 miles away.
No - if it's an USAAF exercise...then it's STILL combat aircraft of whatever class trying their best not to be observed - and they STILL got detected and intercepted. "Civil" Aircraft where civil aircraft were not supposed to be would alert the defenders faster.
That same page also points out that the radar of the day could NOT pick-up low flying aircraft at all, which is just the height that my 3 ATL Mavis would have been headed for in order to drop their torpedoes.
By they time they drop their torpedos 650 FEET from the spillway gates at the end of a long and level approach run, the minimum distance required to arm a Type 91, they'd have been under observation from the ground from quite some distance over the Lake. Also, you ALSO do posit that they need CLOUD COVER to avoid detection til they reach the dam. The last time I looked, tropical cloudbanks don't hug the ground...
I know that a Mavis is not the fastest warplane on the planet but one can cover 15 miles in just less than 5 minutes at it's attack speed of 184 knots. Little time at all for the American fighters to find them, with no radar vector, when they were flying "down in the weeds" on the last leg of their attack. That twin 20mm "tail stinger" could be nasty.
As for being "down in the weeds" you are already QUITE aware that the hills surrounding Gatun Lake were filled with military posts, that has been made quite clear by BOTH the press article from the journalist who talked to the men manning them AND the men supplying them...AND by the Japanese "head of station" who reported defences around the dam and gate control building. You are now trying to be disingenuous to argue your point.

And as for that rear turret...don't you think pursuit fighter pilots were TRAINED to press in attacks against such an armament?? Or do you think that ALL the camera gun footage of such attacks dating from the Second World War is spurious or theatrical reconstruction??? :P

As for finding them and intercepting them at ANY point in their overland flight...a Mavis is at least 130mph SLOWER than a P-40 of any mark :lol: :lol: :lol: In other words - TWICE AS FAST as a cruising Mavis!!! :o
...but there's STILL no way of getting the third in between the elevator towers without loosing about half the tail.. -I have no intention of taking this ATL Chitose conversion discussion down to the level of how many paint brushes would be required. Since the IJN had sufficient qualified marine designers on staff to design the Chitose in the first place, I don't think it improbable to believe that those designers could have re-designed her to carry 3 Mavis as deck cargo.
You WILL argue the point down to that level if you insist the ship you mandate for the attack can carry 33% more aircraft than physically possible. We're not talking about coats of paint, but large chunks of aircraft having to be cut off. Seeing as those qualified designers DID design her in ONE particular way for ONE task - it would be VERY pertinent to see if there were any major issues wth the design that preclude a MASSIVE central crane AT ALL. Let alone proved that the IJN would approve changes to the Chitose's structure that would preclude its later conversion to a full through-deck carrier as intended...compared to the dubious benefit of a pinprick attack with so many points-of-failure in the plan, not least those indicated by their OWN intelligence head-of-station!!!

And you STILL haven't said when you think that conversion for this specific attack would have been carried out. And yes it IS pertinent.

Prove your point or concede it. Trying to avoid the point by foisting it off on the designers to solve is a cop-out. Appealing to some out-of-sight deus ex machina doesn't swing an argument. If you've spent SO much time on all of this - yet NOT found so much that I have found in the last few days arguing against the possibility of success....then you've either been focusing on the wrong things, or not doing the work in the depth you describe. It's hard after all to miss several Presidential Executive Orders entirely, unless the blindness is intentional...
the previous source that I posted here lists the Mavis's empty weight at 12,025 kg or about 13 tons each, not 23 tons each.

Please try to keep up.
And exactly WHERE in the sentence "Two H6k Mavises - even empty - STILL weighs in at TWENTY-THREE TONS" do you see the word "EACH"??? :lol: :lol: :lol: Please try and keep up your reading skills up to the mark.

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#284

Post by phylo_roadking » 01 Feb 2009, 19:21

The last time I looked, tropical cloudbanks don't hug the ground...
Oh, I nearly forgot...where they DO i.e. at altitude up mountains and things like that, with which Panama is quite well-endowed...it DOES tend to create quite a flying hazard for aircraft. Quite a FATAL one - given that there can be slight problems with avoiding oncoming mountains when flying in cloud to escape observation... 8O 8O 8O

Now - let's add to THIS inconvenient little wrinkle the fact that the Mavis' cruising speed is 138mph and the Galapagos islands are some 850 miles away...which means that by the time the attack force arrives over the Canal Zone any weather reports they receive from agents on the ground before they depart are AT LEAST six hours old! - which is MORE than enough to arrive and find that things have changed to clear blue skies with no chance of concealment...or ten-tenths cloud cover at zero altitude and a storm in progress, especially in the Tropical rainy season! So the attackers EITHER have a big metaphorical target painted on them in the shpe of Pan-Am colours....OR end up playing chicken with inconvenient mountainsides that don't know the rules about pulling aside at the last minute :lol: :lol: :lol:

Let's see - a list of minor WWI operations that were weather-dependent over the target or targets...hmm - Pearl Harbour, D-Day, the 1944 Ardennes offensive....

:P Points of failure...

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Re: Dec.7'41: A Day That Nobody Bombed Panama !

#285

Post by robdab » 01 Feb 2009, 19:42

phylo_roadking, you wrote
On 2 September (1939) the 19th Wing ordered France and Albrook fields to be prepared to "place in readiness the maximum force possible" to search the sea lanes approaching Panama, to escort vessels within that limit, and to intercept any foreign planes flying over the Canal Zone without permission. A combat crew roster was prepared, icluding every officer in the wing with the exception of the commanding general and the two base commanders, Lt. Col. Adlai H. Gilkeson of Albrook Field and Maj. Edwin J. House of France Field. The 16th Pursuit group was ordered to be prepared to ooperate patrol and interception missions with six planes, ...
It wasn't to keep six aircraft in readiness, it was to be ready to use everything available for six-aircraft patrol and interception sorties. That is a VERY different situation to what you described up the thread.

My upthread reference as you call it was to page #168 of AAFHS-42 which referered to a March 8'41 order which superceeded the Sept.2'39 6 aircraft order that you quote above. Just 2 (two) armed warplanes were to be kept on 5 minute daylight ground alert for the purposes of checking out commercial aircraft. That would be the same 5 minutes that it would have taken my 3 fake "China Clippers", if spotted at all some 15 miles out from the Canal Zone, to reach their Gatun Dam target. By the time those 2 US interceptors even got off of the ground, my 3 Japanese warplanes would be ready to drop their 6 torpedos (or whatever on whatever since we know now that torpedoes won't do the job needed).

In other words the CAA had full authority and regulation of airspace over the Canal, and thus all regulations WERE to Washington standard;

Why can you not grasp the fact that all the Canal Zone regulations in the world wouldn't matter if my ATL Japanese simply chose to ignore them by flying "cross-country" over Panama to only enter the Canal Zone's airspace for the last 5 minutes of their attack flight ?

Without a functional radar sytem that coverd the whole of Panama and it's offshore approaches, the American defenders would not even know that 3 aircraft were not obeying their precious regulations.

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