What IF: The Dec.7'41 Pearl Harbor Attacks Included a Blockship ?

What IF: The Dec.7'41 Pearl Harbor Attacks Included a Blockship ?

The original timeline (OTL) Japanese historically secured American permission for their 17,000 ton fast cargo-liner, the Tatuta Maru (also spelled Tatsuta Maru), to again pass thru Honolulu Harbor (HH) on Dec.9'41 as part of her second citizen repatriation voyage from Yokohama to San Francisco (SF) and back again. Stops in Panama and Mexico to pick up Japanese citizens there were also advertised in local papers. Gordon Prange's book "At Dawn We Slept" documents those truths, as well as the historical Oahu visits of three previous repatriation liners (pgs. 313-319), with the Tatuta Maru (TM) being one of those previous three. Confirming the details on page #380 is Wohlstetter's book, "Pearl Harbor: Warning and Decision" which can be pre-viewed
http://books.google.ca/books?id=pO4JxYdXP04C&pg=PA379&lpg=PA379&dq=KGU+Honolulu+1941&source=bl&ots=H3k7Dn7BnE&sig=u2cZPvF9guLs3m8qCPOGzmjK07k&hl=en&ei=RP4GSu7YGJDWMIOG4aIG&sa=X&oi=book_result&ct=result&resnum=8#PPA380,M1

Obviously, the TM never actually arrived there on Dec.9'41 in light of the OTL sneak attack visited on Oahu on Dec.7'41. She turned back towards Japan in mid-Pacific at 0200 on Dec.7'41. Her entire historical trip was a deliberate "planned hoax" designed to lull American suspicions of war, as per Prange's page 444, but WHAT IF, in addition to the historical two air raids, my alternative timeline (ATL) Japanese had attempted something more sinister with her instead ?

The Dec.9'41 Honolulu Harbor visit date approved by Washington was the one of Tokyo's request so an ATL advance of that date to 0700+/- on Dec.7'41 instead wouldn't have been at all difficult with some Japanese advanced planning. Messages #220, #237 and #239 at http://142267louis0j0sheehan0esquire.wordpress.com/2009/01/15/lima-peru-chosen-for-gold-deposits-for-emergency-use-louis-j-sheehan-esquire/ show that such schedule changes were indeed historically granted. Message #253 there confirms that Japan's Tatuta Maru historical hoax continued on until the very last possible day. Message #284 is also interesting as it details that the TM also had American permission to visit Balboa, the western end of the Panama Canal ... long another ATL attack interest of mine.

I'd suggest that lots of floating smoke candles, a high powered radio jamming suite and several well disguised/hidden 6" deck guns would be wisely required for any such Tatuta Maru blockship attempt. Along with two new stern anchors, an auxilliary steering room installed well below decks and multiple triple wired demolition charges designed and placed so as to quickly blow her bottoms out once triggered. As built she was 585' long, had a draft of 28' and was 84' in height from keel to maindeck. With superstructure rising well above that.

About 50 real unfortunates historically did buy tickets in order to return on her to Hawaii/America in those troubled political times. Those poor souls would be quietly arrested as they boarded her in my ATL and would be removed from that cargo-liner, into captivity, by a Japanese warship once the Tatuta Maru was well out of sight of Japan's coastline. She would then turn to a rendezvous with the Kido Butai (KB) in the Kuriles, for the trip to Oahu.

While on the officially Washington approved trip to Hawaii, my Tatuta Maru would have been able to scout well out in advance of the Kido Butai air attack force, risk free, and would have afforded Nagumo an ability to send coded messages to Tokyo via her active radio transmitter. While still keeping his entire KB strikeforce otherwise radio silent. Much more flexibility for Nagumo would result.

At the appropriate time the Tatuta Maru would seperate from the KB strikeforce and forge on ahead on her approved schedule for Honolulu Harbor while the 6 IJN carriers stayed 200 miles to the north of that island to launch their air strikes. She would proceed down the western shoreline of Oahu, transmitting all the way, in an attempt to keep American attentions focused far away from the lurking Kido Butai.

About an hour after sunrise, which was at 0606 that morning, she would pass the US Coast Guard Cutter (USCGC) Tiger as it searched for a fishing sampan off of Barber's Point at the southwestern tip of Oahu. From there, a 92 degree turn to port would send her on the final leg of her scheduled and Washington approved Honolulu Harbor port visit.

A few waving TM crew members in the disguise of civilian passengers would line the TM's railings to complete the illusion of normalicy.

Awaiting her arrival at 0730 would be the American gateguard destroyer, the USS Ward, that morning, which habitually prowled a 15 knot, 2 mile by 2 mile peacetime "patrol box" just off the entrances to both Pearl Harbor and Honolulu Harbor, which were located only some 6 miles apart. As could have been easily reported by the prime Japanese secret agent on Oahu, Yoshikawa of the Honolulu Consulate. It's second floor and roof offered fine views of Mamala Bay and the American gateguard destroyer patroling there.

Please see the map to be found at http://ibiblio.org/hyperwar/USA/USA-WH-Guard/maps/USA-WH-Guard-2.jpg

As we well know now, historically 5 Japanese minisubs had been released from their 5 full sized IJN "mothersubs" some hours previous with orders to sneak thru the Pearl Harbor (PH) entrance channel and into that military anchorage and once the OTL air attacks began therein, to torpedo USN warships.

In the case of my ATL scenario however, those 5 minisub's orders would be altered. Since any attempt to sneak past the sonar equipped Ward and the twin anti-submarine nets that closed the PH entrance at night was risky and likely to alert the still peacetime USN, all 5 would be ordered to attack the patrolling USS Ward instead.

As that American gateguard destroyer moved to intercept the expected Tatuta Maru, she would have to slow to a stop in order to transfer, by launch, the Honolulu Harbor pilot to that big 17,000 ton repatriation cargo-liner, as had been done three times before.

That would be the time for my 5 ATL minisubs to strike by surprise with some of their 5x2 = 10x18" torpedoes. Ward's guns were but a small threat to a 17,000 ton Tatuta Maru blockship effort but her 12x21" torpedoes could easily be fatal to any such attempt so she HAD to be sunk, as quickly as was possible. Best done while the USS Ward was a "sitting duck" stationary target that didn't even know that the IJN had developed minisubs.

Immediately after the first explosion on the Ward, the Tatuta Maru's radio jamming suite would be powered up and her twin deisel engines would accelerate to swing her sharply to port, towards the Pearl Harbor entrance channel and away from her officially approved Honolulu Harbor entrance. Her military crew would now be frantically dropping floating smoke candles off of her stern to aid in screening her from the awakening 4x155mm panama mount "examination battery" guns, located on Sand Island in order to watch over both harbor entrances. While not "in their seats" 24/7, the gunners of that battery were ordered to be "ready for action" within 30 minutes or receiving any alert order.

If still appearing to be able to put up a fight, the wreck of the USS Ward would be engaged by those of the Tatuta Maru's hidden 6" deck guns that could bear as she passed by. Accelerating to her maximim of 22 knots would take the Tatuta Maru thru the (kept wide open in daylight) PH anti-submarine nets in some 10-12 minutes after Ward's torpedoing.

The question being, would those sounds/sights at about 0745 alert the American defenders of Pearl Harbor to the incoming Kido Butai air attack wave that historically bombed beginning at 0755 ? I think NOT since the OTL attack by the Ward on a minisub at 0645 generated NO such historical reaction at all. Guns and depthcharges were used and Ward sent not just one but rather two radio messages to her Pearl Harbor HQ reporting her defensive attacks. All that happened was that she was asked for a confirmation, many minutes later. In the case of my ATL, no such confirmation could come from the quickly sinking USS Ward, thru my TM's radio jamming.

Another two or three minutes would allow her perpendicular placement within the 1,000' navigation width of that 40' deep PH channel. Dropping her 2 original bow anchors and her two newly fitted stern anchors would keep her in position to largely block that channel as her bottoms were blown out and she quickly settled the 12' into the thin layer of silt that coverd the dredged channel bottom coral.

Please see the forground of the arieal photo located at
http://www.history.navy.mil/photos/images/h89000/h89041.jpg for a better appreciation of the Pearl Harbor entrance channel.

Since Yamamoto himself had orderd that there be no deliberate suicide attacks made at Pearl Harbor, a "faint hope" escape plan for her scuttling crew would see them launch a fast speedboat or two for a quick trip back out into Mamala Bay. A pick-up by one or more of the 5 big IJN mothersubs out there would be similar to the escape plan scheduled for the 10 OTL minisub crewmen.

As the Tatuta Maru settled, the 5 still secret minisubs would be following her into that murky Pearl Harbor entrance channel and taking up positions around her. There to wait on the bottom in silent ambush for any USN warship attempting to squeeze past her sunken bulk and out to sea. Since the USN was competely unaware of Japan's minisub program, no one would be watching for either a periscope or a torpedo track as they came slowly down that channel. A second US blockship might soon add to American misery.

Of course, the other side of the equation must be discussed, that of the extensive American coastal artillery corps (CAC) instalations built on both sides of that PH entrance channel. They were indeed ... impressive.

On the western shore was Fort Weaver with it's Battery Williston's 2x16" guns while the eastern shore of that channel was home to Fort Kamehameha with it's long list of CAC defenses. Battery Closson (2x12"), Battery Selfridge (2x12"), Battery Hasbrouck (8x12" mortars), Battery Jackson (2x6") and Battery Hawkins (2x3") were all located there. Fort de Russey's (2x14" and 2x6") guns were located just a few miles to the SE on the Waikiki beach shoreline of Honolulu City.

All in all, an impressive amount of coastal defense firepower EXCEPT that on a peacetime Sunday morning, none of it was manned and ready to fight. Since General Short had only orderd a Level #1 anti-sabotage alert for his entire command, sentries were on watch against sabotage at the guns but full gun crews were NOT ready and awaiting their orders to fire. General Short expected many hours of advanced warning time from Admiral Kimmel's long ranged PBY air searches around Oahu but unfortulately Admiral Kimmel did not let General Short know that such recon flights wer NOT being flown, at all.

Some of the lighter CAC pieces might have been quickly brought into action against my Tatuta Maru blockship after a time delay needed for the gunners to man and find ammunition for their pieces. Please remember though that my ATL Tatuta Maru WANTs to sink within that PH entrance channel so American CAC shell impacts, once she is firmly anchored there, will be wholely to Japan's benefit by speeding her sinking.

Since most US CAC fire would be directed at her bridge/wheelhouse, my ATL Japanese would have equipped that ship with a hard to hit auxilliary steering position located for protection, deep within that blockship, as previously mentioned.

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I believe that just such a surprise blockship attack might well succeed in blocking the Pearl Harbor entrance for some weeks/months.

Gentlemen, I request your thoughts/opinions, with sources in support please ...

 

A very interesting twist, with the possibilities of totally bottling up anything that wasn't stuck in the mud.

On the one hand, one wonders if the Japanese would think that far outside the box. On the other hand, they did think to use an ocean liner in the autumn of '41 to scout out the northern route that the fleet would use.

I look forward to further discussion.

DaveBj

 

Here we go again.

Attempting to block Pearl Harbor would be an extremely risky enterprise, one quite likely to fail for the following reasons;

The Japanese liner Tatsuta was authorized to enter Honolulu Harbor, not Pearl Harbor. There was an exclusion zone around the entrance to Pearl Harbor and any unauthorized ship entering it was to be immediately fired upon and sunk.

The gate guard destroyer did not carry a pilot for Honolulu Harbor and therefore would become highly suspicious of any vessel requesting that she stop to transfer a non-existent pilot. In any case, this destroyer would NOT stop and therefore would NOT become an easy target for either torpedoes or gun fire.

Despite the potential armament carried by your imaginary block ship, the Wickes class was armed with four 4"/50 caliber guns which would be capable of at least stopping a merchant ship. A small fast (25+ knots) vessel like the USS WARD would make a very difficult gunnery target; the Tatsuta Maru would not.

A commotion involving gunfire and a smoke screen in front of the Pearl Harbor entrance channel might not attract the attention of the senior officers responsible for the defense of Oahu, but would certainly be heard, and observed, by the junior officers in charge of Pearl Harbor's defenses. They would be most likely to exercise their initiative and open fire on any Japanese ship attempting to enter a US naval base.

In any case, any blockage of Pearl Harbor would likely last not more than a few days, as it would receive the highest priority for removal; Navy engineers would make liberal use of explosives to reopen the entrance channel to Pearl Harbor. The Japanese would realize this and would be unlikely to expend the valuable resources necessary to create what would, at most, be a temporary inconvenience for the US Navy.

 

The USS Ward had already sunk one Japanese midget submarine in the restricted area and their crew were probably still at GQ. Any incoming Japanese ocean liner wandering stupidly into that same restricted zone would be under severe scrutiny by both the officers and men on the Ward's Bridge and the men on its gun directors and torpedo mounts, ticking out firing solutions.

 

One might also note that the dredged channel into and out of the harbor was widened to 1000 yards prior to the war..... You might cause a hazard to navigation but you are not going to completely block it.

Aside from that simply sinking a single block ship would have done little to close the harbor. At most you are looking at a couple of weeks, a month on the outside. The US was the foremost naval salvage nation at the time and would have quickly cleared the wreck by one of several means.
Booby trapping it does no good either once that is known, the US would have just blown the wreck up and pounded the remains into the bottom of the channel in days. Yes, this was done many times during the war.

 

One of the three repatriation liner trips thru Honolulu that I mentioned.

Glad to know it. Welcome aboard.

 

I certainly hope not. I'm NOT going on a weekend fishing trip this weekend so hopefully no moderator will lock down this thread because I haven't responded for a couple of days, as happened last time around.

My understanding is that the PH exclusion zone only had "shoot on sight/contact" orders for unexpected submerged submarines not accompanied by a USN surface warship.

Hence the USS Ward's immediate OTL attack on that IJN minisub first spotted inside the exclusion zone by the USS Condor and then later on by the USS Antares.

History also records that a civilian sampan tried to take an afterdark shortcut thru that exclusion zone on that same night but was intercepted by the Ward. Rather than sinking her "on sight", a small US Coast Guard cutter was called out of Honolulu Harbor to escort her back for further questioning.

My understanding is that the USCGC Taney carried the Honolulu Harbor pilot during daytime hours while the gategard destroyer (the USS Ward on Dec.7'41) did so for the hours of darkness. A military tug delivered the Pearl Harbor entrance pilots.

But how quickly ? Eventually, sure. But what about over a sprint distance of only 3 miles, when that 17,000 ton mechant ship WANTS to sink at the end of it's run ?

Not if Ward was stopped by a torpedo hit(s) and close by. But in any case, I thought minisub torpedoes to be a better and much faster way. Probably just one but maybe two would be needed send the surprised USS Ward to the bottom, very quickly. Well before she could hope to arm and bring her own torpedoes to bear.

No doubt, but the question is, how long, once thay had overcome their surprise and actually decided to open fire on a passenger liner carrying AMERICAN CITIZENS that they KNOW to be authorized by Washington to visit Oahu, would that really take ?

What if the USS Ward turned out to be the victim of an accidental magazine, torpedo or depth charge explosion ? Opening fire on a civilian liner would, in that case, be a career ending move (CEM) for that junior officer(s). I'd expect some minutes worth of "dithering" while information was gathered, careers were evaluated and minds were made up.

The OTL case of the USN officer who ordered "fire and rescue crews away" to the USS California is a classic example. Even though Japanese warplanes were flying overhead, history records him as initially thinking that the US battleship had suffered an accidental explosion and fire rather that a deliberate Japanese attack. That was how confident the American defenders of Oahu were that Hawaii would not be attacked by the Japanese. A similar delay of only a very few minutes would allow my Tatuta Maru blockship to cork the PH entrance channel.

Once they had actually decided to do so, how long would it take those junior officers to roust their gun crews, get those men out of their Sunday morning peacetime bunks/messhall/church services and over to their artillery, then transfer ammo and powder from the locked (remember that anti-sabotage alert ordered by General Short) armoured doors of their magazines, to those CAC guns, so that they were finally ready to fire on my blockship ?

Remember that my Tatuta Maru would already be in the PH entrance channel some 10-12 minutes after the USS Ward exploded.

Once in that channel, any US CAC hits on my Tatuta Maru just speeds the sinking of that intended blockship.

Hmmmm, a difficult choise between using the limited number of USN hardhat divers to rescue still living USN sailors trapped inside the sunken battleships of Pearl Harbor OR diverting same to begin the clearance of a 17,000 ton blockship ? A tough and possibly morale destroying choise for Admiral Kimmel to have to make on that day of infamy.

I claim no ship salvage experience but I think it likely to take many more than just "a few days" to dismember and clear a 17,000 ton blockship. The USS Nevada, for example, drew 28' - 6" of water so in a channel dredged thru coral to only 40' deep, no piece of steel taller than 11' could be left behind if her delicate screws and rudder were to survive the passage out of PH.

Unless my ATL Japanese had further, short term, mayhem in mind.

 

John,

If you were to re-read it you might notice that my ATL scenario specifies a change to the attack orders of the 5 IJN minisubs. They are NO LONGER ordered to attempt to sneak thru Pearl Harbor entrance channel where one was historically spotted by the USS Condor and later on by the USS Antares who both handed off their sightings to the gateguard destroyer that night, the USS Ward.

As I previously detailed in my ATL scenario, they would INSTEAD be stalking the USS Ward in her usual 15 knot 2 mile by 2 mile "patrol box". Although an old "4 stacker", the Ward was equipped with up-to-date sonar but at 15 knots such would be largely useless for hearing any other underwater noises.

Hence she would be unlikely to realize that she was being stalked by 5 examples of a submerged weapons system that the USN did not even know existed on Dec.7'41.

My Tatuta Maru wouldn't be "stupidly wandering" anywhere since she had OTL approval to call in at Honolulu Harbor. My ATL would just advance the historical Dec.9'41 date by two days to Dec.7'41.

Expected and approved by Washington.

Please, give it a quick re-read.

 

Page #34 of the Williford & McGovern authored Osprey Fortress series #8 booklet entiled, "Defenses of Pearl Harbor and Oahu 1907-50" indicates dredging to 1,000' (not yards) by 1938.

A quick look at the modern day NOAA navigation chart #19364 should convince you that the Pearl Harbor entrance channel was never dredged to a width of 1,000 yards.

Really ?

How does one "pound the remains into the bottom of the channel in days" ? Some 17,000 tons of "remains".

Especially when that channel bottom is a "rock hard" ancient coral barrier reef that took many months and tons of explosives to dredge thru.

 

So, the Ward's lookouts aren't going to question all of the periscopes popping up all around her to get a firing solution and the guy minding the destroyer's sonar equipment is going to be asleep at the switch too? By the way, if the Ward was patroling at 15 knots, the sonar would still be effective. Once she reached 17knots, the sonar would be useless.

Remember too, we're talking about midget submarines here. They are not exactly state of the art equipment and very much likely to broach whenever they're operating at shallow periscope depth. Remember, the reason the Ward sighted the sub in the OTL is because its conning tower was above water as it was following the USS Antares. That sub skipper probably thought that only his periscope was above water and not his entire conning tower.

As soon as the Ward goes to GQ, Condition Zed will be set and all watertight doors will be dogged down tight, so that even if she does eat a Japanese torpedo, she will most likely stay afloat long enough to get off a radio message alerting PH as to what happened.

Lastly, like Terry wrote earlier. The approach into the harbor had recently been greatly widened, so that a single block ship couldn't do what you propose.

 

"There are no problems in this life that are all too encompassing, nor insurmountably great that cannot be corrected through the proper application of high explosives."

 

I was guided by Norman Fiedman's book entitled "US Destroyers" which states on page #196 that:

"The high-speed submarine can avoid standard echo-ranging search, and our listening gear is masked by our own ship noises at speeds of 15 knots and above."

And that comes from a November 1945 report on American Pacific Ocean ASW efforts. If 15 knots was the upper limit in 1945, I'd certainly expect the masking speed to be lower, rather than higher, for a less advanced 1941 peacetime sonar installation in a noisey old WW1 era "4 stacker" like the USS Ward.

Certainly the 5 IJN minisubs present at PH were capable of extremely high underwater speeds on their electric motors, even though they had NO on board means of recharging their storage batteries.

Sigh.

As I have pointed out to you twice already and now for a third time, my 5 ATL IJN minisubs would NOT be following any US ships up the Pearl Harbor entrance channel. THEIR ORDERS ARE CHANGED IN MY ATL SCENARIO !

Since the USN's gateguard destroyer always patroled the same "box" out in Mamala Bay, within easy sight of the Japan's Honolulu Consulate, the location of the USS Ward would already be well known to those 10 Japanese submariners. Few periscope "peaks" would be needed to close on her known "patrol box" and those could be done at very low speed so as to not raise a "periscope feather" of spray.

With a shiny, big 17,000 ton cargo-liner moving in right in front of the Ward to distract their attentions, how many peacetime US lookouts would really be paying much attention to the search for minisub periscopes that the USN did NOT even know existed at that time ?

I'd suggest, none at all.

OTOH, I believe that the first likely reason that the USS Ward would have to go to GQ would BE her eating of the first IJN minisub torpedo.

Sigh.

Yet again, had you actually READ my ATL scenario you would have noted that it already INCLUDES a radio jamming suite installed on board my Tatuta Maru blockship. To be warmed up and ready to turn on as soon as the first explosion engulfs the USS Ward.

Sigh.

As per my latest response to Terry, which it seems that you have not yet bother to read either, he seems to be mistaken in his recollections of the dredged width of the Pearl Harbor entrance channel.

In an effort to improve upon the success of my ATL Tatuta Maru blockship (or to correct her errors, depending on your PoV) my scenario ALREADY includes the assistance of the 5 IJN minisubs (at least those that still have torpedoes aboard after sinking the USS Ward) which are ordered to follow HER into the PH entrance channel. There to take station in the murky channel waters around her scuttled bulk while awaiting the first attempts of escaping USN warships to slowly squeeze past her. A second USN blockship might thus be added to more thoroughly block that passage.

With luck, the American defenders might believe that the Tatut Maru had laid a few mines on her way into that single entrance channel and so STILL not realize that the Japanese Empire had invented workable minisubs, in total secrecy, and that 5 such still lurked inside of the PH anti-subamrine nets.

I had indeed considered converting the ATL Tatuta Maru into a concealed minelayer but thought the risk of an accidental American CAC gunfire hit on the mines stored below decks to be too much of a risk to her entire blockship mission. Besides which the USN had numerous small draft minesweepers moored within Pearl Harbor in 1941. Any planted minefield would soon be cleared by that flock so there was no point in such that I could see..

 

Just as matter of interest, who was it that first said that ?

I'd guess Alfred Nobel but it would be just a wild guess.

Quite possibly true but I'd point out that you would still need to have large quantities of waterproof explosives and detonators "on hand" and the great amount of TIME needed to emplace them within a darkened waterfilled ship laying in a (now) shark infested harbor.

The historically spilled USN blood could not help but lure hordes of them into Pearl Harbor from the open ocean.

 

You might want to check out how the USN cleared the channel into Port Bizerte in North Africa. There the Germans piled 28 ships in four rows and had wrecks piled on wrecks to block the channel.
The USN cut the ships into sections using high explosives and then pounded the remaining wreckage into the bottom using low grade explosives. Within a week the salvage crews had sufficently cleared the channel to allow passage of ships one at a time. The whole job took just under a month and roughly 400 tons of explosives.

As for salvage assets, the USN was in relatively good shape locally at Pearl Harbor as well.
There were sufficent officers and men available at Pearl Harbor to execute the most important salvage operations immediately.
There was a civilian contractor (Pacific Bridge Corporation) working for the USN in Hawaii with expertise in underwater concrete and heavy underwater engineering.
Local industrial and civilian ship repair companies had an excellent amount of cranes, hoisting barges, and other salvage equipment available.
Salvage gear contracted from the salvage firm Merritt-Chapman & Scott was on the West Coast and in Hawaii prior to the outbreak of the war.
The repair ship Vestal while damaged in the attack, was still operational
The USN had several floating cranes, lift barges, and pontoons were already available.


Now, if the USN can manage that in North Africa how hard will it be for them to remove a single ship from the Pearl Harbor channel?

 

Those midget subs may be capable of high speed, but for a duration of well less than an hour before their batteries were spent. Also, the USN knew all about the Japanese midget submarine program, so they were no secret. I recall hearing a radio broadcast from the late 1930's, whereby a member of congress was warning America about Japan's expansionist ambitions in the Pacific and their "infernel miniature suicide submarines..." that could make surprise attacks on shipping in US harbors and etc. The message was, "keep a close eye on Germany, but beware of Japan's ambitions as well." That was taken fron the Longines Symphonette Society History of Radio Collection. circa 1939.

My point about the midget subs not being state of the art, is that they were very difficult to trim to maintain their balance and commonly broached the surface, so that their conning tower was oftentimes out of the water while they were using their periscope to make a torpedo shot. Once the torpedoes were fired, this became a certainty because of the sudden loss of ballast in the bow, causing it to break the surface. By the way, the subs would need to look through their periscope to line up a torpedo shot on the Ward. The Ward's lookouts might miss a periscope, but not four or five submarine conning towers bobbing around like corks in the restricted area? I'm sure that the Ward would most likely go to GQ and set Condition Zed following these midget sub sightings.

Also, don't forget about the patroling PBY Catalinas out of Kanehoe Bay that were flying off the entrance of PH that morning. Whether you are talking about the OTL or the ATL, they were up that morning on patrol. If the Ward suddenly explodes from multiple torpedo hits and their trails leading back to the midget subs are plainly visible from the air, then this is probably going to alert the powers that be in the harbor. By the way, there's more than one frequency on the radio dial to the US forces on shore, so it would be difficult to jam them all.

 

I see that now we are getting more reasonable. We've gone from "just a few days" to "just under a month" to clear a blockship from that channel.

I only want 10 hours.

No doubt.

Ah, but as the old saying goes. "The Devil is in the details".

If the Germans scuttled 28 ships averaging 600 tons each at Bizerte, I would be impressed with the American obstruction clearance rate. I haven't been able to find much related to that event on the WWW but if it was 28 fishing boats averaging only 60 tons each then I won't be nearly so impressed.

Was the Bizertee channel bottom of soft mud or of (almost) rock like the Pearl Harbor channel's coral reef base ? The depths at Bizerte are also most important. 'Rwould b much easier to leave scarp steel on the bottom of that channel if ther was more clearance than the 11'-6" to be found at PH.

Details, details ...

 

So ? At 19 knots it wouldn't take long to fool an ASW attacker that expected the usual 6-9 knots underwater. From Nihon Kaigun: Type A-class it is seen that at 6 knots the IJN minisubs had a range of 84 nautical miles at 6 knots. More than enough for the new ATL PH mission that I assign them. With a reserve for crew rescue purposes.

I was under the impression that the Allies only knew of them as "floating gunnery targets" made for IJN target practise.

[QUOITE]My point about the midget subs not being state of the art, is that they were very difficult to trim to maintain their balance and commonly broached the surface, so that their conning tower was oftentimes out of the water while they were using their periscope to make a torpedo shot. Once the torpedoes were fired, this became a certainty because of the sudden loss of ballast in the bow, causing it to break the surface. By the way, the subs would need to look through their periscope to line up a torpedo shot on the Ward. The Ward's lookouts might miss a periscope, but not four or five submarine conning towers bobbing around like corks in the restricted area? I'm sure that the Ward would most likely go to GQ and set Condition Zed following these midget sub sightings.[/QUOTE]

Even if a minisub should broach after firng a torpedo, as one historicaly DID inside Pearl Harbor, I just don't see a stopped Ward getting out of the way nor getting to GQ status before a short distance torpedo shot slammed into her.

[QUOT]Also, don't forget about the patroling PBY Catalinas out of Kanehoe Bay that were flying off the entrance of PH that morning. Whether you are talking about the OTL or the ATL, they were up that morning on patrol. If the Ward suddenly explodes from multiple torpedo hits and their trails leading back to the midget subs are plainly visible from the air, then this is probably going to alert the powers that be in the harbor. [/QUOTE]

My blockship attack was carefully planned around their daily flights. In the OTL one stayed behind to aid the Ward's attck on a minisub by dropping a smoke marker float near that minisub at about 0645. The other two of the usual 3 PBY patrol continued south at 0630 to check the US Fleet's usual operating areas some 30 miles to the south of Honolulu.

In the case of my ATL there would be no minisub trailing the Antares towards the PH entrance channel so there would be no need for that PBY to stick around for another 45 minutes to see a blockship in action.

There is no need to be patronizing.

Of that I am well aware. A broad specrtrum jammer is not all that difficult to build. I can do so with two wire coathangers, a pair of piers and a furnace transformer, provided that I have 110 volt power available. I feel reasonably secure in thinking that the Japanese military's radio engineers of the day could manage to put a good one together since they could build radios capable of good trans-Pacific performance..

 

My point was, you didn't have to fire a torpedo in order to have a midget submarine break surface, just taking a periscope bearing would do, as it historically happened in the OTL. The midget submarines were very difficult to trim. Lastly, there is no way to determine where a PBY will be at any given time, but I can assure you that if a Japanese ocean liner were trying to enter Pearl Harbor, rather than Honolulu Harbor, the pilot of that navy patrol bomber would think that strange, given the actual international events of the time.

 

Terry, I note that you have yet to post any serious details wrt to sizes of the 28 ships that the Germans used to block Bizerte. Since you don't, I can only conclude that each of the 28 was but a lifeboat in size and thus much morre easily cleared that a scuttled 17,000 ton cargo-liner would be.

I am gratified however to see that you are indeed taking my blockship scenario seriously but alas, in this case, not so.

Page # 93 of Burlingame's book, "Advance Force: Pearl Harbor" clearly indicates that the twin Pearl Harbor anti-torpedo nets (they weren't of a heavy enough construction to be considered anti-submarine nets) were kept OPEN from sunrise to sunset. My blockship would pass thru at about 0745, some 99 minutes after sunrise, hence, NO possibility of her becoming tangled in those nets, at all.

Similarly, the previously mentioned Williford & McGovern Osprey Fortress series booklet indicates on it's page #44 that NO controlled minefields were operational around Oahu during WW2. I must confess that I can't remember (at this moment) where I read it but I believe that those WW1 vintage controlled mines were removed in 1929 due to wildly accelerating maintenance costs from their constant immersion in salt water.

As far as I can tell, my ATL blockship still seems to be "on course and schedule" to cork the Pearl Harbor entrance channel.