What if...the Japanese had landed troops in Hawai'i immediately after bombing Pearl?

When I responded to this message of yours earlier I accidentally overlooked your 16" comments for which I must apologize.

Please have a look at the totaly open nature of the Oahu 16" gun installation pictured at 16-inch Gun on M1919 Barbette Carriage and then tell me that it was not vulnerable to KB bombing and/or IJN shellfire. There is absolutely NO cover for the CAC gunners who would man that piece. Even a straffing Zero would decimate the guncrews, time after time,

A two man sniper team would silence that gun for hours.

A hit on the generator building pictured would knock out the power supply that rotated the gun's turntable.

No mgs, no foxholes, no defensive trenches, not even a FENCE protect the gun turntable from being overrun by a small "commando style" force of JSNLF who had crept close thru the surrounding pineapple fields, at dawn.

A 16" defensive gun emplacement sure SOUNDS impressive but when you look closely at how it was ACTUALLY done on Oahu before Dec.7'41, not so much.

 

Wow, that was quite an impressive rant.

Since I don't wish to waste any more of your time, this is the only response that I will make to it.

At least until I have caught up in my responses to previous messages from other posters here.

Have a nice day.

 

They did have a lot of cargo ships that were basically sitting at anchor just prior to the start of the war. The embargos had hit their commerce enough that many were left without cargo.

Much of the rest of his data looks like it could come from the Hawaian invasion thread over on the axis history forum.

 

Glad to see you back urqh

Snipers........excellent

Silenced pistols and wearing American uniforms using night infiltration training..........good lord man you're talking Ninjas!!

This thread has turned the corner from informed intelligent discussion to knuckleheaded banter

 

I do not propose a two division landing force for the night of Dec.6-7'41. I send in the CF and just 9 troop carrying ships, 3 big IJA hauing cargo-liners and 6 ex-DDs with JSNLF troopers.

How would a (rare) night time training flight spot darkened ships at night, especially ones that they weren't even looking for ?

Have you any proof at all that there were ANY training flights (be they civilian or military) flying around north of Oahu on the peacetime liberty Saturday night of Dec.6-7'41, or is such just wild speculation on your part ?

Were there ? Have you any proof or is this yet more guesswork on your part ?

The usual Honolulu to San Francisco shipping lanes ran to the southeast from Honolulu, past the big island of Hawaii and then turned to the northeast. Inter-island traffic between the Hawaiian Islands ran to the NW and SE from Oahu since that is where the other islands lay in relation to Oahu.

Neither is likely to send any shipping traffic to the north of Oahu from where my invasion force will be arriving.

An odd assertion when we know that the OTL Japanese expected to have two of the KB's 6 carriers sunk and another heavily damaged during the PH air raids. A 50% expected loss rate sure seems like acceptance of high risk factors to me. Doesn't it to you ?

I note that this list is for Dec.7'41, NOT of the night of Dec.6-7'41.

I see the Enterprise TF inbound from 200 miles west, the Lexington TF outbound at 750mile WNW of oahu, 3 American subs inbound from 200 miles to the east, a US DD + submarine some 60 miles SW of Oahu and a heavy cruiser and 4 minesweeers exercising 25 miles south of Oahu.

Please explain how any of those might have seen my ATL CF and/or the 9 invasion vesses that I have ordered to sweep into Oahu waters at 20+ knots, thru the darkness. from the north ?

If one somehow did, what would stop the 8 (or 9) IJN battleships from quickly smotherling it with broadsides ?

Both the US Army and the USN were constantly running training exercise and drills on, around and above Oahu so none of that islands residents would be at all surprised to hear the sounds of gunfire and explosions, day or night. The flash of distant naval gunfire would just be attributed to yet another round of USN gunnery training.

Witness the OTL example of the USS Ward's sinking of an IJN minisub at 0645 on Dec.7'41 with gunfire and depthcharges. No one on the nearby shores raised any alarm and even Ward's twice broadcast combat report failed to get the attention of America's Pacific Fleet before the KB's bombs/torpedos began to fall at 0755.

Yet right after Doolittle raided Tokyo, they did indeed hurridly approve Yammaoto's plan to invade (a by then much better defended) Hawaii.

If you refuse to allow any PoD then we will never be able to discuss any Alternative History will we ?

Yet again I state for the record, I propose NO assault landings on Oahu.

There were no defended beaches on Oahu on the morning of Dec.7'41. No mines, no barbed wire, no trenches, no foxholes, no tanks, no machinguns, no cannon and most importantly, NO US troops at all. Those were tucked safely in their bunks at Schofield Barracks and Fort Shafter.

The situations that you try to compare here are not at all similar. By the time that the OTL Japanese got to Miri on Dec.17'41, the Pacific War had been underway for 10 days. 'Twasn't a surprise.

And when do you think that a fleet of anything had last anchored off of Miri ?

In the cae of my ATL Japanese landings on Oahu, I propose just one darkened cargo-liner (not a FLEET by any definition of the word) anchored off the beach at the far end of the Bellows Field runway where the US Marines often conducted their own beach landing exercises. If the few US anti-sabotage sentries who guarded the USAAF warplanes parked at the other end of Bellows Field could see anything thru the darkness at all, I'd think them likely to assume that yet another US Marine training exercise was on, at least untl it was far too late to sound any warning at all.

For my other cargo-liner troop landing inside Kaneohe Bay, what resident of Oahu, on a still peacetime liberty Saturday night would be at all alarmed by yet another deep draft merchant ship anchoring in the darkness, midway between the too shallow Port of Kaneohe and the still being built Kaneohe NAS ? Of course there would be noise as a swarm of small barges appeared around it to carry it's cargo to shore, half to the Port and half to the NAS. Business as usual until the point after dawn when it was finally discovered that "the cargo" was really IJN troops. But even then, as per the many eyewitness testimonys posted in the internet, many of Oahu's residents would still think my ATL landings to just be a very realistic part of yet another of General Shot's endless training exercises.

How could any Americans know that once ashore, my 6 boatloads of JSNLF troops had been busy cutting the overhead telephone lines that ran around the island on poles installed beside the oceanfront perimter ring highway. Oahu was far too mountainous to run telephone lines any other way.

 

Well, until you can respond to my questions and the issues I have raised, I'll consider your arguments as being invalid.

Thanks, I am having a whole series of nice days.

 

That is certainly where the idled tankers come from.

Yes indeed. In exchange for my aid in researching Oahu's Dec.7'41 ammunition supplies, Glenn239 was kind enough to allow me to "poach" much of his basic research. Please note however that Glenn239's "Operation Tinkerbell" invasion of Hawaii proposal was/is a long slow effort based on taking many of the other Hawaiin Islands so that Japanese land based aircraft could be brought in and based there on newly constructed/expanded airfields. Only after weeks/months of bombing would actual Oahu landings finally begin.

In my less than humble opinion, such a long duration seige type of effort would play into known American strengths:
- such a plan would allow more than enough time for the US Atlantic Fleet (maybe with Royal Navy help ?) to arrive off of Hawaii in an attempt to lift the seige.
- such a plan would force the Japanese to make combat assault landings on (by then) heavily fortified and firecely defended Oahu beaches, something that they tried very hard to not have to do.
-such a plan would not take advantage of the stunning effect of a surprise attack on a peacetime Oahu.
- such a plan would allow the American defenders of Oahu to deploy their large stockpile of chemical weapons
- such a plan would allow the Americans time to deploy the thousands of defensive sea mines that were stockpiled on Oahu
- such a plan woud give the USN much needed time to redeploy more submarines to Hawaiian waters
- such a plan would give Oahu's American defenders the time needed to move Oahu's civilian population (and their food supplies) to more easily defended mountainous locations
- such a plan would allow the US Army time to re-distribute their ammunition out of the centralized (and easily interdicted one entrance road) Aliamanu Crater Ammunition Depot.
- such a plan would leave the American CAC in full control of thier 100+ ridgeline observation bunkers so that Oahu's coastal artillery could play havoc with Japanese invasion shipping.
- etc.

In other words, his was/is an all too sensible American "style" invasion, not a "shoestring" Japanese "style" landing, at all.

As such was the case, I have worked with Glenn239's basic data in order to design a much faster, "instant invasion" scenario which I hope is more in the overly complex and confused Japanese "style" of Pacific island warfare. "Risky" and "shoestring" to be sure.

There are certainly changes within the data. For instance, you will note that my ATL plan includes the French Frigate Shoals whereas Glenn239's
"Operation Tinkerbell" does not.

 

Adding personal insults won't do much to improve the situation, now will it ?

At the least, Japan had a cultural history of ninjas.

Since you don't seem to like my tactical ideas, lets look at what the OTL Japanese actually did do, shall we ?

- a brand new mechanism for shallow depth torpedo drops was designed, tested, refined, produced, deployed and VERY successfully battletested, in a period of 3 short months, all in great secrecy,
- the never before tried concept of fighting 6 carriers in one concentrated formation was used against Pearl Harbor
- 16" AP battleship shells were redesigned and modified as AP bombs and used to destroy tyhe USS Arizona and some 1,100 of her crew at PH
- a secret to the world minisub and mothership program was used in the Pearl Harbor attacks.
- a totally unexpected and very successful air attack was made over an unheard of 3,400 mile distance in complete secrecy EVEN THOUGH American code breakers had previuosly broken many of Imperial Japan's codes
- the Zero fighter was deployed in nimbers, with a long range drop tank, at a time when the USS Lexington still carried but 18 Buffalo fighters that were grounded just a few days later due to collapsing landing gear struts.
- In Thailand, a private bus carrying a load of civilian dressed IJA soldiers (and several rented bar girls) was used in an attempt to sneak across the Malay border at the time of Kota Bharu.


And you can't accept something as simple as some American looking uniforms and a few silenced pistols ??

 

Ok. I'm a bit confused as to eacatly what ships are moving in what groups toward Hawaii and when. Care to clarify this a bit?

Where are they going and how are they getting there and how long do you think they can/will hold out?

how about the naval patrols?

How likely is it to be picked up by radar?

How about the reefs in the area? How good is your navigation?

That's going to raise the alert faster than a radio message. But the odds are they are going to be leading with DDs so the BB line isn't likely to be the first thing spotted or spotting.

Not to observers or many in the military. An engagment sounds different than a practice and many with experiance can tell one gun from another.

So what happens if these become assault landings?

Not quite right. I'm pretty sure some of the defences were already in place. In particular there is mention at: http://hiavps.com/Bellows.htm
of

Note that this also means the coastal artillery is zeroed in on this area already.

Then there is this quote form: 25th Infantry Division Association: Pearl Harbor

 

So, for all practical purposes it hadn't yet arrived, had it. It was still on a ship, not yet in the gunner's hands (and thus not yey signed for) and those American gunners had not yet had the chance to undertake any firing practise at all with their "new toys' before the OTL Japanese attacked.

Do we really need to "play silly buggers" with word games here ?

From The Siege of Corregidor I present,
"The only weapon in the armament of the harbor defenses with the high trajectory required to deliver effective counterbattery fire under these circumstances was the 12-inch mortar. There were twenty-two of these pieces on the four islands, but their usefulness against land targets was limited by the lack of sound ranging equipment and the shortage of ammunition with instantaneous fuzes. There was an ample supply of armor-piercing, fixed, delay fuze ammunition with a small bursting charge. This type was designed for use by coast artillery against warships but was of little use in the situation in the Seaward Defenses then faced. These shells buried themselves deep in the earth before exploding and caused little damage to men and installations near by. The ideal ammunition against the targets presented by the Japanese guns on the Cavite shore was the personnel type with instantaneous point detonating fuze. There were about 1,000 such shells, of 12-inch caliber and weighing 670 pounds, but even this small amount could not be used freely, for it would be desperately needed when Bataan fell and the enemy placed his heavy guns on the slopes of the Mariveles Mountains.
A small quantity of additional instantaneous fuze ammunition was obtained as a result of experiments made by Colonel Bunker. He modified the fuze of the 1,070-pound shells used in the 12-inch guns by removing the .05-second delay pellet, thus detonating the shell more quickly. When he test-fired two such shells he got "beautiful results, up to my wildest hopes." The effect, he noted, was equal to that of a personnel shell, "both in dirt thrown up and in noise made,"[27] But thought the modified projectile exploded on impact, it had only a small bursting charge and a limited effect. Thus, despite every effort to secure effective counterbattery fire, the Americans were never able to prevent the Japanese from firing almost at will."

Which seems to idicate to me that the American seacoast 12" mortar was not be greatly feared by my ATL Japanese invaders.

They might do some but only if my ATL Japanese 1.) get within their range and 2.) the Americans have a spotter with BOTH line of sight AND a method of communication back to those CAC mortars.

As I have already pointed out, my ATL Japanese horses would only be taking a 3,400 nmiles @ 20 knots = 7 day sea voyage so I just don't agree with your predictions for their incapacitation.

 

Not according to Professor H. P. Willmott. In his Chapter in "The Pacific War Companion" (edited by Daniel Marston), Willmott makes the point that of the approximately 10 million tons of shipping utilized by Japan prior to the Allied embargoes, about 4 million tons were actually either neutral- or Allied-flagged. In most cases, the cargoes affected by the various embargoes were shipped in these non-Japanese controlled vessels. Moreover, since the embargoes were successively imposed over more than a year, there was no immediate and precipitous drop in available cargoes. Because at the same time, Allied shipping requirements were increasing at a very rapid pace, and much of the neutral/Allied shipping servicing Japanese needs were being requisitioned for the European war effort.

The net effect of this was that there was no glut of idle Japanese-controlled shipping due to the embargoes. In fact, I remember reading a message sent by one of the Japanese embassy in Thailand in the fall of 1941, complaining that a Japanese company operating there could not find any Japanese shipping company willing to take a cargo of much-needed raw rubber for shipment to Japan.

In John Prados' "Combined Fleet Decoded", there is mention of the fact that, in the four weeks prior to the outbreak of the Pacific War, the Japanese Navy had recalled almost every Japanese ship that normally plied the world's trade routes; these ships were held in ports, of which the Japanese expected to retain control. Normally there was something like 200-300 Japanese merchant ships at sea on any given day, but by the first week in December, 1941, there were less than half a dozen. The US ONI agency noted this at the time, but other than indicating a Japanese expectation of impending hostilities, there was no other conclusion they could draw. This represented a serious curtailment of shipping for the Japanese, but these ships were anything but idle, and their inactivity lasted no longer than a few days immediately after December 7. These vessels were certainly not "available" for any invasion of Oahu

It probably does. This is a hobby horse for this guy, and I've seen the same lame arguments on several boards.

 

That would explain it then. I can see some interpreting the fact that most of the Japanese merchant fleet was sitting in harbor on 6 Dec as them being inactive and that being due to the embargos.

 

Sorry you took it as a personal insult as it was only intended to insult the direction the thread was going

Do you really think that would be effective? You have these troops magically appearing on shore with out being detected whatsoever. Any sub large enough to deliver a preliminary advanced force, large enough to accomplish anything, would have been detected by the very active ASW patrols and sunk.

Where are these areas that they are going to attack? Don't you think that when American sentries are found with bullet holes in them that someone might figure out something is out of the ordinary?

You assume too much. In order for any preliminary raiding force to move quickly enough on land in 1941 Oahu they are going to need roads and vehicles. Two diplomats stealing a bus is rediculous. All roads leading from the beach were actively patrolled by local police and MP's. Hawaii was in a state of modified martial law in Dec. 1941 which restricted unecessary travel in vital areas.

I believe DA chimed in after me and has extrapolated on my criticism of your plan and it's lack of presentation. You obviously missed the sarcasm.

DA and I rarely see "eye to eye"

Then why should they use silencers at all, why wouldn't they use their powers of diversion and throwing stars to accomplish the mission?

Your tactics are incredibly unsound. You extoll the virtues of a successful raid that took years to plan.

The IJA/IJN only made successful landings twice against American Defenders: Wake and Guam............every other time they were pushed back into the sea.

The underwater topography of Oahu does not lend itself to amphibious assault, that is why the Marines practiced at Maui, Lenai and the other Islands. There are two approaches to the Island that would allow for a support ship/ troop transport, of any usable size, to get close enough to disembark troops or landing craft and those are Kaneohe and Pearl Harbor. Both of which approaches were heavily patrolled by the Navy.

Now lets look at the tide tables in order for your troops to land they would have to do so prior sunset on 6 December because of the tide patterns inherent to Oahu. Oahu has a Semi Diuranl tide pattern which means that there are a High tide, a Highest High Tide, a low tide and a lowest low tide and they cycle every 6 hours. So at sunset on the 6th was highest high tide follwed by the lowest Low tide that reached it's lowest point at around 6 AM 7 Dec. So your landing troops that landed after sunset on 6 December would be traveling against the tide and any support ships would run the risk of being beached in the low tide.

The best ocean conditions for any type of amphibious landing on Oahu is broad daylight 8AM- 4PM and even then boats that were capable of landing vehicles or horses would need to find the deeper approaches of Pearl and Kaneohe.

I will remind you again that if the Japanese had even the slightest thought that an Amphibious assault of the Island of Oahu could have been successful they would have done it.

I am sure that Japan had much better tacticians than you in their war chest and all of them decided that Oahu was not an option.

The bottom line is that the occupation/ assault of Oahu was not tactically significant to the Japanese and was therefore non essential to their conduct of operations.

 

Note that this is exactly the sort of thing the army was looking for. They were on antisabotage alert.

 

Anyone else notice that the originator of this thread, "LiebstandarteSS", has abandoned it?

Does that make us all guilty of "Thread Piracy" ?

 

I cannot agree, Yoshikawa and others of the Honolulu Japanese consulate officially had free run of all of the Hawaiian Islands EXCEPT for the interiors of the American military bases thereon. Prange however reveals that Yoshikawa was most resourceful at gaining access. He waited tables in disguise at American military dinner parties, rented civilian airccraft for sightseeing flights over all of the islands and took up "bird watching" as a bs hobby so that he could walk Oahu's mountains with binoculars and look down into the American military bases spread out below.

The 155mm GPFs and the 240mm howitzers, once field emplaced, fired from pre-poured round concrete "panama mount" bases that could be seen simply by driving by in a car or even more easily from the air. Ditto for the specially strengthened "firing sidings" built for the railway car mounted artillery. The topography of Oahu means that both roads and railways have to be built nearly side-by-side and are thus easily visible, one from the other.

Modern day google earth satelite photos certainly show the ridgeline CAC observation bunkers clearly enough so I can't see how/why Yoshikawa would have missed them during his numerous airbourne civilian sightseeing flights or while making "bird watching" hikes along those same ridgelines.

'Tis news to me. Is there a source that I can consult to educate myself further ?

Certainly the wartime American's knew nothing about Yoshikawa's pre-war 1941 activities on Oahu until he wrote a book on the subject in the early 1960s. He was arrested along with all of the other Consulate staffers after Dec.7'41 but was traded back to Japan in exchange for US Consulate staff similarly detained there.

Yes indeedy. Many (but not all) of the CAC plotting rooms and ammunition bunkers were gas proofed too.

I like the following list since it seems more useful and only lists bases existing on Nov.30'41, unlike your list which includes some built after the OTL Dec.741 atacks:

The deployment of the Army garrison at Hawaii on November 30th, 1941:

Strength by Unit and Station, Nov 30 1941.
(PHA, Vol 12, p320)
Location...........................Men
Barking Sands....................70
Bellows Field.....................409
Camp Malakole, Oahu.......1,395
Fort Armstrong..................818
Fort Barrette.....................133
Fort De Russy....................542
Fort Kamehameha............2,171
Fort Ruger.........................897
Fort Shafter....................3,415
Fort Weaver.......................346
Hawaiian Ord. Depo.............262
Hickam...........................5,378
Hilo, Big Island...................468
Homestead, Molokai..............97
Hononlulu............................50
Lihue, Kauai.......................200
Schofield Barracks...........22,179
Tripler Hospital...................404
Wailuku, Maui.....................455
Wheeler Field...................3,257

Total: 40,469 men, 2,490 officers.

It was planned that this force would be augmented from the West Coast after the start of hostilities:

Initial War Garrison, Hawaiian Department.

Department HQ - 683
Beach and land defense - 23,550
Hawaiian Air Force - 8,802
Harbor Defense - 6,220
Anti-Aircraft Artillery - 8,993
Service Organizations - 5,911
Hospital Forces - 3,009
Service command - 83
Total - 57,241

Including:
North Sector triangular division - 11,445
South Sector Division - 11,161 (PHA, Vol 30, 2601-2605)

Of the additional troops absent at the time of attack but authorized and required in wartime was the garrision for Kanoehe Bay - like the west coast of Oahu, the east coast had next to no troops assigned to defend it. The defenses of the outlying islands were also entirely inadequate,

Location.................Men
Kauai.......................70
Hilo (Big Island).......468
Molokai....................97
Lihue, Kauai............200
Wailuku, Maui..........455

Certainly the often mountainous December surf on Oahu's north shore precludes that possibility, as do the concentrated American CAC guns lining Mamala Bay on Oahu's southwestern corner.

Oahu's west coast offers several possible landing beaches and reasonable surf heights since the prevailing winds in December blow winter storms in from the northeast. The narrowness of the relatively flat coastal strip would tend to choke the beachead expansion capability of Japanese invaders there though. And American troops from Schofield Barracks could quickly be overlooking any Japanese coastal landings from the Kole Kole Pass high above.

The Kaneohe Plain on Oahu's SE corner seems to offer the most likely mass landing locations even though it does lie on Oahu's Windward Coast. The barrier reef protected Kaneohe Bay would serve as a sheltered anchorage in all but the most abysmal weather and was virtually undefended at the time.

I have often wondered if would have been better for the OTL Japanese to have ordered their 5 minisubs to torpedo the USS Ward when the KB's air attacks began so that they could then station themselves in ambush positions just outside of the PH entrance, It seems to me that trying to sneak inside of Pearl Harbor itself was just too likely to risk exposing the entire OTL attack for little likely gain to be achieved by just 5x 2 = 10 torpedos of just 18" size. Yet another "what IF".

I am not proposing an American style beach landing from several miles out. My 2 cargo-liners will anchor very close to shore and will run themselves agound if necessary (a' la Guadalcanal) to ensure that their lightly equipped invasion troops can quickly get ashore.

I agree that once the shellshocked and stunned Americans recovered from their initial surprise, it would indeed be one hell of a fight for the mountainous Oahu. I do believe thought that the surprise that I describe would have allowed my ATL Japanese invaders ashore in numbers sufficient to make a fight of it.

Since no one here has yet had the courage to reply to my question from my posting #35, let me ask YOU personally what events you think would have caused General Short to surrender Oahu ?

Being that I not yet been able to present all of my ATL scenario for the Invasion Of Oahu in it's entirety, I hope that you will "stick around" long enough for me to convince you that it MIGHT have been done successfully.

 

'Tis a fine source but not "fine grained" enough in this case. For instance, the 155mm "panama mount" firing bases mentioned were poured in late December 1941 when it was realized, after the OTL Pearl Harbor air raids, that the Kaneohe Plain was virtually undefended.

Likewise, faulty concrete had cracked when the massive 240mm howitzers had fired so those round mounts were demolished during the summer of 1941 so that the expensive (and long production time) steel traversing ring gears could be reused elsewhere.

The Journals of the Coast Defense Study Group (CDSG.org) are available on CD and provide a wealth of detail on Oahu's coastal defense artillery installations. The Oahu articles therein written by William Gaines and John Bennett are particularly relavent to this discussion.

But wasn't watching on Dec.7'41.

And how would the USN have known that the Japanese battleship was within 100 miles of Oahu ?

Oh the firing sidings were built alright, but save for 2 at the Brown's Camp training station on Oahu's SW corner, the 8" railway guns were all "back in the barn" for longterm (out of the rain) storage. General Short was relying entiely on Admiral Kimmel's (non-existant) long range PBY patrols to give him adequite artillery deployment warning time before any impending attack on Oahu.

My readings indicate that for a large variety of reasons/causes the Americans defending Oahu on Dec.7'41 were indeed "asleep at the wheel".

The list goes on and on and on ...

I've never seen the movie but I understnd that it was filmed in the Schofield Barracks on Oahu just a few years after WW2 and would clearly show the concentrated multi-storey barracks buildings that I propose be bombarded by my 8 (or 9) ATL Japanese battleships.

All I can say is that the OTL Pearl Harbor air strikes clearly showed the falacy of his belief, didn't they.

True enugh I guess but as an author one hopes that ones critics will at least do some good research first.

Many thanks. It seems rare here for posters to pass out anything but attack after attack so receiving some recognition for a well defended arguement is much appreciated.

 

If my memory serves me correctly, I believe that Rommell expected the allies to hit the beaches at high tide for the invasion of Normandy. The logic was that they would have had a shorter expanse of beach to cross after landing.

Bob Guercio

 

There wasn't one save for a cutter that patroled Mamala Bay outside the entrance to Honolulu Harbor (HH). It (usually the USCGC Tiger overnight and the USCGC Taney during the day) was there to provide harbor pilot transfer to merchant ships entering HH and to aid the PH gateguard destroyer, the USS Ward on Dec.7'41, when needed. It might wander as far west as Barber's Point in search of stray fishing boats etc but rarely ventured farther.

There were 400+ fishing sampans operating out of Oahu in 1941 with most being "long liner" tuna boats that fished fairly close to shore in daytime only. Most were open boats that relied on sails for their motive power. Without engines since engines were expensive and requred expensive fuel. Without an engine one cannot provide the great amounts of power required by a 1941 vintage radio transmitter. No doubt some boats would carry a radio receiver powered by a car battery so that they could receive weather warnings but I have found no reference to radio transmitters being carried (and I have looked).

The marine radio transmitters of the day were not the small units that we so take for granted today. They were large, heavy, delicate and would take up valuable catch storage space.

Something like 97% of Oahu's fishing boats were owned by fishermen of Japanese descent at that time. Beginning in 1939 the US Coast Guard authorities (fearing that fishing boats might meet Japanese submarines off Oahu's shores for future sabotage purposes) had begun a crackdown on illegal aliens (mostly from Japan and Korea) who paid large fees to have themselves smuggled to a better life in Hawaii and worked the fishing fleet. Many boat owners were fined when it was found that they had employed illegal crewmen so there was a heavy feeling of resentment building towards the US authorities by 1941. I can't see why any of those fishermen would be at all eager to report a darkened warship to American authorites even if they did have a radio transmitter on board.

Is that "sure with a source" or just "sure".

 

These weapons can also be fired from their wheeled field mountings like any other field artillery. All the Panama mounts do is allow them to easily traverse 360 degrees for use in the coastal defense role. As field artillery they would be devastating. The Japanese land forces once their naval forces are forced to withdraw within a few days at most due to lack of fuel will be pummelled by American artillery that vastly outnumbers their own in quantity, qualtiy, ammunition supply and, above all fire control.
The railway mountings were designed to use the civilian railway that circles two thirds of the island. Yes, there are special sidings for their use but they could just as easily fire from the existing track along its entire length at any point if necessary.
As it was the Japanese didn't know of more than a few of the Panama mounts and had ignored the sidings in their "spy" efforts. This is most likely due to their use of civilian diplomats who were not trained or specifically instructed in what to look for.

Well, he did. Could it be he didn't have a Google subscription?

The one time the Japanese drove their cargo ships ashore at Guadalcanal cost them over 50% of the material aboard. Yes, the men got off but very little of the cargo. Here the defenses will soon pummel the beached and still largely loaded ships into burning wreckage.
Doing this as an expedient helps in the initial assault but will cost the Japanese in the days to come as ammunition runs out and their troops are reduced to fighting with bayonets and whatever captured weapons they can scrounge.
A mass of lightly armed men is not what it will take to win. The Japanese need heavy weapons and artillery. Without these they are going to be reduced to trading heavy casualties they cannot afford for lack of firepower they don't have.

The US military telling him that he can expect no reinforcement and things on the island are deteoriating into chaos. But, if the US military tells him that reinforcements are on the way from the West Coast I would expect him to continue the fight with the growing hope that those troops would soon arrive.
Just prolonging the battle to two weeks finishes the Japanese effort. Their supplies will run out and no more will be coming. Their fleet will have left simply because they cannot support it at sea that far from a base that long. Without air support, without artillery and heavy weapons they are fighting a losing battle. The US need only hold until reinforcements show up which is almost a certainty.