Amphibious invasion of Pearl Harbor - results

[Bullwinkle58]

ORIGINAL: John Lansford

Mike,

Thanks for the exact numbers. My book on the history of Oahu coast defenses mentioned the 155mm mobile guns and the preselected mount locations but I'd forgotten just how many were there. Sixty 155mm guns firing from all angles at both the men on shore and the ships offshore would have been a complete nightmare, not even taking into account the 5", 6", 8", 12", 14" and 16" guns firing too, plus divisional artillery and any ships damaged but still operational in the harbor itself.

Except, as the link I posted shows, they weren't there in January 1942. By the time they were, Midway had happened, and an invasion was a pipe-dream. (Or more of one than in January at least.)

Bullwinkle,

The IJN will have charts but no way to take sightings on where they are once they get to Hawaii. Do you think the navigational lights and lighthouses will be operating?

No, but the mountains don't move. Crossed bearing fixes on geographic features are a staple of piloting, especially pre-radar. BBs had pagodas high enough to get a fix and still stay below the horizon.

 

They will have errors in their positions and even a small error means they aren't shooting accurately at anything at night. Please show me where any navy managed to disable fixed fortifications by shooting at them during night time. The USN certainly didn't attempt it in the Pacific

,

No, the USN had overwhelming force, didn't have surprise, and didn't face "world-class" CD systems like Oahu's. Could they have done it? Yes, I think so. With a lot of effort and doctrine development.

BTW, Barber's Point is in range of nearly every single fixed gun position on the south side of Oahu. Good luck with having your fleet sitting offshore at that location.

A lot of the bigger guns were near PH, and just getting to Barbers eats up over half your range. Facing Barber's Point there were very few large guns. Also, as I said many posts ago, I assume there would be CAS involved from an intact KB. Were the 16-inchers improved from this 1920s installation? Were they in casements by 1942? Because these look awfully like pre-air-power assumptions to me.



http://www.cdsg.org/home.htm

[John Lansford]

In my game the AI attempted an invasion of Dutch Harbor, home of a base force, NorPac HQ, a few AA units and IIRC an infantry regiment.  The CD guns embedded in the base force took on the invasion TF, hitting several transports before they began firing back "to suppress the CD guns".  The invasion TF had a PB trying to suppress the gunfire but the CD guns took it out fairly quickly and then the transports took over the job themselves.
 
That, IMO, is a crock.  If I've got 155mm or 5" or 6" guns firing at transports, and no warships to attempt to silence them, then the popguns on the transports are just making my spotters and aimers' job easier.  I realize that the developers have said that the routine assigns a ship to suppress CD fire, and if no warship is available it uses a transport, but that's ridiculous.  Any transport that tried that would be turned into a shell ridden target in short order.

[John Lansford]

Bullwinkle,
 
The long range 16" guns were emplaced in fortified caves at a position NW of Pearl Harbor and just north of Barber's Point.  Their coverage area extended from all up the west coast over to Waikiki; Barber's Point was no problem for them at all.  Besides, there were a lot more guns available closer to Barber's Point than 16" guns, most of them in disappearing mounts or barbettes.  When I get home I'll look up what was at Oahu in 1/42 and let you know; I'm fairly sure a sizable number of those 155mm mobile guns were already there.

[Bullwinkle58]

ORIGINAL: John Lansford

In my game the AI attempted an invasion of Dutch Harbor, home of a base force, NorPac HQ, a few AA units and IIRC an infantry regiment.  The CD guns embedded in the base force took on the invasion TF, hitting several transports before they began firing back "to suppress the CD guns".  The invasion TF had a PB trying to suppress the gunfire but the CD guns took it out fairly quickly and then the transports took over the job themselves.

That, IMO, is a crock.  If I've got 155mm or 5" or 6" guns firing at transports, and no warships to attempt to silence them, then the popguns on the transports are just making my spotters and aimers' job easier.  I realize that the developers have said that the routine assigns a ship to suppress CD fire, and if no warship is available it uses a transport, but that's ridiculous.  Any transport that tried that would be turned into a shell ridden target in short order.

I'm not sure of your point. That, unless X escorts of Y size are available, the AI should stay home? Or that the transports should violate orders and abandon a critical invasion because they got fired at? What?

It's a simplified algorithm that doesn't consider thousands of variables both pro-invader and pro-defender. I think it's a big improvement from WITP that the invader has a chance to supress CD, and the player gets some feedback on this. In WITP it was all magic behind the curtain.

[jackyo123]

ORIGINAL: Bluebook


--------------------------------------------------------------------------------
Amphibious Assault at Pearl Harbor

TF 99 troops unloading over beach at Pearl Harbor, 180,107

Japanese ground losses:
125 casualties reported
Squads: 7 destroyed, 0 disabled
Non Combat: 25 destroyed, 0 disabled
Engineers: 0 destroyed, 0 disabled
Vehicles lost 1 (1 destroyed, 0 disabled)



10 Support troops lost from landing craft during unload of 21st Div /7
17 troops of a IJA Infantry Squad accidentally lost during unload of 21st Div /8
10 Support troops lost overboard during unload of 21st Div /9
10 Support troops accidentally lost during unload of 21st Div /10
10 Support troops lost overboard during unload of 21st Div /10
10 Support troops lost in surf during unload of 16th Infantry Rgt /5
19 troops of a IJA Infantry Squad accidentally lost during unload of 33rd Div /10
19 troops of a IJA Infantry Squad accidentally lost during unload of 4th Div /4
10 Support troops lost from landing craft during unload of 4th Div /4
10 Support troops lost overboard during unload of 4th Div /4
10 Support troops lost from landing craft during unload of 4th Div /4
10 Support troops lost in surf during unload of 4th Div /5
10 Support troops lost in surf during unload of 4th Div /5
10 Support troops lost overboard during unload of 4th Div /5
10 Support troops lost overboard during unload of 4th Infantry Rgt /5
19 troops of a IJA Infantry Squad lost overboard during unload of 4th Div /6
10 Support troops accidentally lost during unload of 4th Div /6
10 Support troops lost overboard during unload of 4th Div /6
10 Support troops lost overboard during unload of 24th Infantry Rgt /3
19 troops of a IJA Infantry Squad lost from landing craft during unload of 24th Infantry Rgt /4
10 Support troops accidentally lost during unload of 24th Infantry Rgt /4
10 Support troops lost overboard during unload of 21st Div /13
10 Support troops lost from landing craft during unload of 33rd Div /14
10 Support troops lost in surf during unload of 4th Div /7
10 Support troops lost from landing craft during unload of 21st Div /14
10 Support troops accidentally lost during unload of 16th Army
Motorized Support damaged beyond repair during unload of 16th Army /4
10 Support troops lost in surf during unload of 16th Army /4
19 troops of a IJA Infantry Squad lost from landing craft during unload of 4th Div /8
10 Support troops accidentally lost during unload of 4th Div /8

The thing that jumped out at me is how ridiculously heavy are the punishment for 'accidents' during amphib ops into udnefended hexes. I've had 300 casualties when unloading unprepped troops into an empty hex. If it happened once or twice per game, well then ok, i would write it off to bad rolls. But there should be a damper put on how many accidental losses you can get when debarking into empty hexes while not under fire.

[castor troy]

ORIGINAL: Graycompany

Castor, What do you see as a good House rule for this. Limiting the number, or perhaps size of ships (Support) in Amphib TF? I would be interested in your thoughts on that.

while I usually come up with a hr about this and that quite fast, hard to think about one in this case. I guess you can´t force someone to do a naval bombardment with x BBs, y CAs, etc or to have x CLs and z DDs in an amphib TF when you attack y target. And I guess the outcome wouldn´t look different when we think about the transports or the troops that are landing, it would only result in some cruisers or BBs damaged/sunk when they have to deal with the CD guns. In this case the 16inch AP shell would hit a BB or CA and not the cheap, crappy PB.

The only thing I could imagine would be to NOT include any escorts for an invasion TF as this would mean the CD would actually fire at the invasion and not in a couple of crappy escort ships in front of them. The main problem I see isn´t even the (not) sinking of the transports, but the fact that there is no firing at the landing troops at all anymore in AE. Well, forget about what you see in the cr when a line says "CD guns firing on troops in landing crafts". This just isn´t happening as there are never any considerable losses. The attacker loses more squads due to accident than due to the strongest CD on the map. This obviously is the result of the rest of the defending ground troops not shooting at the beaches anymore. This was still in WITP when you saw a dozen to a couple of thousand shots fired at an invasion. While you had only a small percentage of shots fired from the CD guns against the ships, you had howitzers, mortars, etc. firing at the troops coming ashore and this was a far better routine than it is now as it´s pretty clear that invading troops don´t suffer at all if the land at a heavily defended hostile base.

So I guess you would have to test it first if an invasion TF wouldn´t be 100% whiped out on the other side if non of the crappy escorts would be in the TF, as I would consider whiping out 100% of the transports completely off too. But one thing is for sure, if you land a couple of divisions on a hostile beach and the hex is defended by a couple of ten thousand enemies with heavy guns for anti ship and hundreds of artillery pieces for anti personell then the attacker should suffer and not bring his troops ashore in a 95% ready state.

[Bullwinkle58]

ORIGINAL: John Lansford

Bullwinkle,

The long range 16" guns were emplaced in fortified caves at a position NW of Pearl Harbor and just north of Barber's Point.  Their coverage area extended from all up the west coast over to Waikiki; Barber's Point was no problem for them at all.  Besides, there were a lot more guns available closer to Barber's Point than 16" guns, most of them in disappearing mounts or barbettes.  When I get home I'll look up what was at Oahu in 1/42 and let you know; I'm fairly sure a sizable number of those 155mm mobile guns were already there.

I'd be interested. I spent a fair bit of time on NAS Barber's Point itself, and I'm not picturing where these would have been. Or how caves could have been dug into sheer lava cliffs, with access for 16-inch ammo. They weren't on the tour.[:)]

In the picture I posted, the caption in the link indicated those were Battery William at Fort Weaver, just barely west of Pearl Harbor itself.

[castor troy]

ORIGINAL: Bullwinkle58

ORIGINAL: WITPPL

It was my CHOICE a well thought out CHOICE not to waste Betties and its pilots not to mention KB pilots and BBs to save some AKLs. Have You ever considered that there is no one way of doing things? Everything is just and only a risk management (what I do for life).

FWIW, in all this "the CD system doesn't work" talk I offer my recent experience taking that bastion of CD science--Wotje Island (huh?) I had the USS Pennsylvania, two CAs, and four DDs supporting a somewhat rambling invasion (hey, it's me, right?) I had two infantry regiments about 50% prepped, a Seabee unit, and a small, non-EAB combat engineer unit. Recon said there were about 5000 troops, about 30-ish guns, and no armor. I had been LBA and dive-bombing from three other islands for two weeks at a low but consistent rate, and had two fighter squadrons strafing daily for a week prior. My best info was there had been no re-supply of the island for about three months. I thought it was a simple mop up op. (Tarawa and Kwaj. hadn't had a whole lot of CD support.)

I got clocked. Two DDs sunk, both cruisers with 30-ish system damge and some float, the BB with 15 system and fires. There was counter-battery fire every phase from my ships, but it didn't put the CD OOC. In those phases I got the troops ashore with tough losses, including four xAKs and serious damage to eight other merchants, but zero, and I mean ZERO, supplies. Every LCU had a big red zero for supplies. I tried to use emergency barges from Mili to get supplies ashore, and lost about twelve, without landing even one ton of supplies.

For a second wave of resupply I used LSTs and DDs, and still couldn't get anything ashore. They got torn up too. (By now the BB and CAs had retired to lick their wounds.) Finally, out of anger more than anything, I ordered shock attacks without supplies, gambling that the Japanese were nearly out of supply. That worked in two attacks, and all three units (a Naval Guard, the Naval Fortress/CD unit, and a support unit) were wiped out.

Curious now, I re-loaded as Japanese and "peeked" at the remaining untaken islands nearby. A couple are CD farms just like Wotje. I may bypass them now that I know. This is, after all, a "learning" run-through game.

But I for one don't believe there's anything in the code that makes merchants immune while the AI focuses on small escorts.

the reason why you had not unloaded a single ton of supplies might be because you had troops and supplies on the same ships. First troops are unloaded and supplies aren´t unloaded until the ship has completely unloaded the troops. Therefore, always bring troops and supply in different ships.

[castor troy]

ORIGINAL: Nikademus

ORIGINAL: Bluebook

Ok, this is going to be a somewhat long post because Im going to quote the combat report in relevant parts.

Couple of comments:

512 shell hits is "nothing"?

2nd: Where was the airforce and the navy?

would say yes. Why? Because most of them were put in not even a dozen PBs. So what´s wrong then? Not the number of shots but the target routine? Or the damage routine that keeps a PB afloat after being hit by shells of 5-16 inch? Something is wrong, at least in my world of thinking when all that is lost are a dozen ships out of 350 and the troops get ashore completely unharmed. And yes, I definetely call this unharmed.

[castor troy]

ORIGINAL: Bullwinkle58

ORIGINAL: castor troy


Clearing the beach? The USN wasn´t able to clear the beaches and destroy the Japanese CD at targets that nearly had the same number of guns. How should the IJN be able to do that in 42? Of course they could clear the beaches that have no defense but those probably are seen as areas where you can´t land anyway. It´s not that easy to disembark a couple of division onto a beachhead that isn´t suitable I guess. Those that were suitable would have CD that isn´t easily cleared at all and for sure not a day before the invasion goes in IMO.

I found this highly macro, 30,000-ft illustration of Oahu's defenses:

http://the.honoluluadvertiser.com/daily ... ws2map.gif

Demonstrably, the planners were defending PH and Honolulu, not the north or west coasts. As I've said, invading PH would have been insane. Kaneohe or Barber's Point, maybe not, at least from a CD perspective.

If you land somewhere where you are not target of CD guns then you can land there with your troops in boats together with their rifles, with probably nothing bigger than a MG or small to medium mortars at best. No heavy weapons, perhaps some small pieces of artillery. You probably can´t land them directly onto the beach so you will drag them through 3-4 feet of water? Supply will be the issue number one, just because you can land all your soldiers, they are not worth a lot with their rifles, ammo, water and food for a day.

[bsq]

It seems to me that the actual position of the guns matters not in a game where terrain is abstracted into 40 mile hexes. The arguments raging back and forth over what was where is irrelevant, the only relevant thing is the number of 'tubes'.

No matter where IRL a particular gun was doesn't matter, the game sees it as a 360 deg mount and will fire it where it will. The other thing is that they will have pretty substantial ammunition stocks - unlike their shipborne counterparts, so unless the invader gets in and out quickly, he will lose the duel.

The CD/Bombardment routines are a bit screwy to say the least and this is just a very spectacular example of this. Any one look to see the stock accuracy of the CD guns that were used on Oahu? Bet some aren't coded as much better than a few percent, yet as has been pointed out, once the range has been found, then the destruction commences.

The day night argument, ignores the fact that whilst you might safely throw shells ashore at night with relative impunity (not that you should hit much), you cannot unload troops at night, therefore during the day, the CD should destroy the troop ships and their consorts - in this AAR they appear not to have.

Finally for those of you who argue about navigational fixing at night to support your 'deadly accurate' night bombardment fantasies - ask your self why lighthouses have coded beams - cos like mountains and other bits of terrain, unless you know exactly where you are, you don't know what exactly you are looking at without some other clues.
So triangulation on terrain alone at night is not accurate cos they are just big black 2D silhouettes that change as you move and unless you know what they look like from every single angle, you're screwed.

[castor troy]

ORIGINAL: mjk428

ORIGINAL: Rob Brennan UK

Kudos on both players for having a really out of the box war ! Wippl for thinking this up ! and BlueBook for taking it on the chin and carrying on !

I hope you both continue to have a fun game (as thats why we play it after all)

Got to say i am v v curious about the next few turns.

Arguing about the exact positon/facing of any CD guns in the game is utterly pointless. We all know that CD guns are treated as units not as historically placed and covering each piece of potential landing space. so stop arguing whats actually impossible to model in game and if you feel its unrealistic then argue ways to improve it, not just cry foul.

If my car is broken I don't have to tell my mechanic how to fix it, I just tell him what the problem is.

I agree with the kudos to both players. Neither deserves to be criticized for exploiting the system or for bad play. The Japanese player should always have the option to put his troops on ships and send them anywhere on the map. The Allied player should reasonably expect that extensive forts and guns would slaughter any invasions without heavy surface support.

I don't know if this particular result is because of the amphib bonus or a bug with the coastal gun routine, probably a combination of both. The amphib bonus is fine when sending tiny units to the many undefended bases the IJN has to secure in the early months. It's ridiculous when it allows troops to instantly jump off ship in the middle of a fight. The Japs were capable of many things but walking on water was not one of them.

I've had Jap troops land fully supplied and capture a base even when I sunk the entire invasion TF (PBs and AKs) on arrival (AE 1.0). That's pure BS. The amphib bonus should evaporate when an invasion is contested.

I´ve already long had the feeling that I don´t lose any troops if my ships are sunk in a base hex, no matter if it is in a friendly port or if it is when I´m invading something. Could there be something wrong in the game just putting everything unharmed ashore when a ship is sunk during an invasion or while unloading at a friendly port? Supplies definetely are lost. Will have to keep an eye on that.

[Chickenboy]

ORIGINAL: Smeulders

ORIGINAL: Chickenboy

ORIGINAL: sfbaytf
I'm waiting for the invasion of San Francisco AAR. Regardless of whether this is "gamey" or not you have to give credit for the audacity and the ability to plan and organize this feat.

Has the attack on Pearl Harbor / Oahu been successful? Did I miss an update indicating that the IJA forces have landed with supplies and have defeated the entrenched American forces?

Shall we see how this audacious enterprise unfolds with the infantry assault before we crown anyone's tactical or strategic genius or assault the game engine?

What happens now to the land combat is completely irrelevant to whether or not the CD gun routine is wrong.

It seems that the main problem is the targeting of the CD guns. Instead of completely gutting the landing ships, which should probably be the priority when you're being invaded, they hit the PB ships. Another strange thing is that the PB ships don't sink during the combat. Looking at the size of the guns and the number of hits, nearly every PB should have sunk. They probably did, but only after the combat, leaving them to soak up a lot of damage that would have otherwise destroyed many a landing transport.

Another problem is of course the Japanese unloading bonus. I know it's necessary to let the Japanese do their early war expansion and it's probably not that unrealistic in the DEI/PI were there was almost no opposition on the landing beaches, but it isn't here. If the ships would have had to stay under those guns for multiple days to unload everything without the bonus, there wouldn't have been much left of the IJN.

The success or failure of this invasion (the big picture) is about more than just the CD gun routine. Ability to deliver sufficient numbers of supplied, undisrupted troops to the fight to capture the objective is what I'm waiting to see.

Rest assured, those PBs sank. FOW is the only reason they're not on the ship sunk list at this point.

The IJN do get the unloading bonus-that's true. This bonus does nothing to reduce disruption or fatigue, only speed to unload, AFAIK. With the numbers of troops that were lost during unloading, I would suspect that these troops were not preparing for Pearl Harbor very long-I tend to lose more troops during unloading amphibious assault forces if I have not adequately prepared for a given target.

I would venture that those IJA troops on Hawaii now are low on supply, disrupted as heck, fatigued and low on prep. Let's see how the attack goes...The 'success' of this venture is not a given-without knowing more about both offensive and defensive settings (beyond the combat report generalities) I'd give it about a 40% chance of success, maybe less.

[Chickenboy]

ORIGINAL: Bluebook

I just checked my sunk ships screen. According to that one (and barring the fog of war, naturally) the Jap losses were:

On the day of the invasion:
1 CL and 2 DD to mines


The day after the invasion:
1 xAK and 1 xAKL to CD guns
2 DD to CD guns
1 DD to mines

He's lost all those PBs and probably a few others as well. It will take time for his lost ships to be 'admitted' and put on your list.

[Smeulders]

ORIGINAL: Bullwinkle58

ORIGINAL: Smeulders
As for the second, it's pretty unrealistic that all the CD guns shoot at the same time, I'd imagine that to unload this kind of force the TF should have been in range for several hours, so if the code would only give one 'round' of fire (even if this means several shells from every CD gun)then this could be modelled better to account for ships sinking during the engagement and thus no longer being a target. I'd indeed be interested to know the devs opinion on this.

I'm sympathetic (increasingly so as I learn more about the game's finer points) to the dev's challenges though. A phase is 12-hours. Do you do one 12-hour "chunk" of calculations? Three 4s? One hour layers? Do you consider that some of the (sometimes hundreds) of ships in range of the CD guns move during those 12-hours? How often and where to/from? Is weather a factor? How often do you do a check on CD supplies? If they run out in the middle of the 12-hours, how do you handle that? How about time-to-sink? Do CD gunners still shoot at a Monty Python-esque damaged ship ("I'm getting better!") or do they look elsewhere? How do they know the damage over there, 12,000 yards away? And on and on. Hundreds of questions we all could pose onto what is only one, pretty small part of the total code base. And, once you make all these trade-offs, how do you present the results so they're clear, actionable, but still concise enough that anyone will read them?

True, I think the devs are doing a great job, but every once in a while something like this pops up. I can't get my head around this mass of CD guns putting enough shells into a bunch of upgunned fishing trawlers to sink them 10 times over, while the transports are happily unloading divisions of troops 10 meters to the right.

I also hear enough reports here of CD guns putting serious damage on an invasion fleet, but it is pretty obvious that the algorithm gets borked by something in this battle, most likely the huge mass of ships/escorts.

[Nikademus]

ORIGINAL: WITPPL

Do You want me to post exact composition of all invading TFs?

Yes. [:)]

[WITPPL]

Screen force used was much larger than quoted here.

I can post a whole scheme of this landing (Yes, All BBs were there!) with exact composition of all TFs included but I am not sure if it is a right time or if this will help anybody.

If You want to, or If this might help then ok.

[Bullwinkle58]

ORIGINAL: castor troy


So I guess you would have to test it first if an invasion TF wouldn´t be 100% whiped out on the other side if non of the crappy escorts would be in the TF, as I would consider whiping out 100% of the transports completely off too.

I for one would strenuously object to any change that forced me to sail an invasion TF 1000 miles with no escorts, just so those escorts wouldn't be shell sponges at the other end. Tasking a surface TF to Follow, even at 0 hexes, is not the same in the code as organic escorts if that transport TF is jumped in transit.

[Chickenboy]

ORIGINAL: Bluebook

ORIGINAL: Nikademus

ORIGINAL: Bluebook

Ok, this is going to be a somewhat long post because Im going to quote the combat report in relevant parts.

Couple of comments:

512 shell hits is "nothing"?

2nd: Where was the airforce and the navy?

512 shell hits is nothing since 80-90 percent of those hits were on the same 8-10 PBs. I actually saw PBs obliterated by 16-inch gun hits only to be hit again and again by other guns after that. It seems that each escorting ship was engaged by all CD-guns at the same time, regardless of earlier hits. So first a 3 inch battery would shoot and hit the PB, then a 6-inch, then a 12-inch, then a 16 inch, then a 12 inch mortar, then a RR gun, then a 155 gun... Nevermind that the PB was already sunk by the second hit. Then the next PB would appear and get the same treatment.

The navy is licking its wounds after having the KB linger around Pearl Harbor for the first week of war. Those ships that are combat worthy are either somewhere else, or they have been fighting the Japs during the battles for Midway, Wake, Johnston, and the rest of the Hawaiian islands.

The airforce... The 50 bombers I have outside CONUS (with experience in the 45-50-range) are right now on ground attack duty. I considered it to be utterly pointless to send those 30 B-17s and 20 B-18s/A-20s against the 80-Zero CAP only to have them drop their bombs harmlessly on or beside the 8 Jap BBs.

I have managed to reinforce Pearl with fighters though, and I think I can muster 150-something fighters to CAP right now.

Where are your subs? He's got the entire IJN here-I'd bring everything from all nationalities back to the Hawaiian islands to try to start attriting some of his ships.

I'd also bring my carriers back from their distractions to defend Hawaii. Don't go picking a fight with KB one on one, but sortie in when he goes back for refueling or for a new torpedo loadout.

[Mynok]

20 to 40 foot waves along the West, North, and East shores. Yeah, a Japanese landing is going to be a real "cakewalk". The whole idea is a crock.

Surfboards! [:'(]