An invasion plan for PM (or any large airbase)

[CapAndGown]

Here are my thoughts on how to conduct an invasion of an enemy held base. This is the method I used to invade Port Moresby.

The core of the invasion force are the troops and supplies they need. Depending on the time frame for the invasion, it may take up to two divisions to conquer the enemy base. For PM, I loaded up the 2nd division in one TF, and the 38th division in another. Both TFs had very compement, very aggressive TF commanders: Tanaka and Kono. For transports I chose almost exclusively the 1000 capacity type. This meant my troops were spread out among lots of transports; if I lost one, it would not mean losing a significant portion of my invasion force. These TFs were set to patrol/do not retire. The lead invasion TF would only be set to retirement allowed when it was one movement phase away from its target. The initial group was timed to arrive just before sunrise to allow maximum time for unloading before my opponent could order his troops to attack.

These two troop carrying TFs where not supposed to both land together. Instead, one would be held in reserve steaming around where the carriers were (more on that later) until it could be determined if reenforcements were needed, or whether the lead division could handle the opposition on its own. Pre-invasion intelligence on expected enemy strength was gathered through high altitude bombing runs on PM. Two of these runs were made just as the troops left Truk. These bombing runs were also meant as a way for my zeros to engage the enemy fighters at an advantageous altitude, 20,000 feet and so weaken his fighter strength. Using recon air craft for such intelligence would probably be better, except the japs don't get any Irvings for a while, and using recon aircraft might tip your hand (though flying in at 20,000 feet on a bombing run with Nells and Bettys might do that as well).

I also formed two transport TFs than carried just supply. These were set to follow the two troop carrying TFs. The reason for having a seperate TF for supply is two fold. 1) It provides an additional target for naval air attacks, such that, if the naval air attacks my supply transports, at least it is not attacking my troops. 2) Both the troops and supply can be unloading at the same time. A TF that carries both supplies and troops in the same ships will unload the troops first. Only after they offload will the supplies start to unload. If you need to make a fast exit, then at least your troops will have some supplies if one TF was unloading
just supplies all along.

I did not escort my transport TFs with surface combatants. More on this later. Let me just say now, however, that I did not wish to subject my suface combatants to enemy air power as they accompanied slow moving transports. I did form an MSW TF to follow the main invasion TF to sweep for mines. I had it follow instead of including the ships directly in the transport TFs because IJN MSW's tend to slow down anybody they are with because they constantly are refueling.

So now we are up to 2 transport TFs carrying two divisions, and 2 transport TFs carrying supply, and one mine warfare TF made up of MSW's. All are set to patrol/do not retire, one supply TF following each troop TF and the MSW TF also following the lead troop TF.

Now the problem with invading PM is that the US is going to have lots of level bombers there set to naval attack. They can wipe out anything in range if they decide to attack it. Therefore, you need to a) put that airfield out of action, and b) make them not want to attack you until you can put the airfield out of commision.

To accomplish (b) you need carriers. Unescorted bombers do not like flying against carriers. Therefore if carriers are in a hex which your opponent's fighters cannot reach, the bombers are very unlikely to attack that hex. Ergo:

Form one or two air combat TF's. In my case, I used two. Set one carrier TF to follow the main troop carrying TF. Set all other ships that are not following the troop carrying TF to follow the lead carrier TF. Set everyone to patrol/do not retire. As long as everyone is traveling together outside your opponent's fighter range, you are somewhat safe.

One carrier TF is loaded with the normal complement of fighters, dive bombers and torpedo bombers. This is in case you run into enemy carriers. The other carrier TF has had most of its dive bombers and torpedo bombers replaced with fighter squadrons. They are meant to provide LRCAP for the transports. 2 squadrons provide LRCAP one turn while 2 squadrons are set on escort with a CAP level of 50%. This allows one squadron to be resting while the other incurs fatigue from LRCAP. Next turn, the squadrons change roles to allow the ones that flew LRCAP to recover from some of their fatigue. So much for air cover.

You also need a replenishment TF following this group to keep everybody topped up, especially your bombardment TFs, to wit:

I also formed 3 surface TFs and set them to follow the carriers. These are meant to bombard PM on a continuous basis. Once the invasion fleet reaches a point where your fastest surface group can reach PM at maximum speed, change its mission to bombardment/retirement allowed with a destination of PM. The following turn, set another surface TF to bombard PM. Meanwhile, the first surface TF will need to be changed back to patrol/do not retire and reset to follow the carriers. On the third turn you send in your third surface TF while your first one refuels from the tankers and your second one is reset to follow the carriers after having bombarded PM. By using three bombardment TFs, you can bombard PM at least 6 and as much as 9 times.

These bombardment TFs can also provide night time protection for your transport TFs. Rather than having them directly escorted by surface combatants (except perhaps a few destroyers for ASW) these bombarment TFs that are racing in and out every night can provide them protection without exposing them to landbased air. If your opponent send in a surface TF during the day, then this obviously won't work. But the carriers should deter this.

The final point is judging how far the carriers should follow the transports. In my case, I allow the carriers to get with 8 hexes of PM. By that time, the airstrip had been closed down due to my bombardments. But I still had to worrying about the planes at Cairns and I wanted to provide CAP for my bombardment TFs. So once the transports were within 8 hexes of PM, they were on their own while the carriers retreated back to the hex where the bombardment TFs ended up at the end of their runs. This way the bombardment TFs did not need LRCAP, they had CAP directly from the carriers and the planes at Cairns left them alone. It was at this point, of course, that LRCAP had to be set over the transports. This was done not only from the carriers, but from Lae and Rabual on a rotating basis.

The composition of the planned invasion then was:
2 transport TFs, each carrying one division in 1000 capacity APs
2 transport TFs carrying supplies in 1000 capacity APs
2 air combat TFs
3 surface combat TFs
1 MSW TF
1 replenishment TF

Finally, just before the invasion fleet made its run into the Solomon sea, there was a general stand down across the theater. Almost all fighters were set to 0% training, most other planes were set to 20% ASW. Everyone was going to be completely rested before the big show began.

In the event, the 2nd division was diverted to Guadacanal to deal with the Australian 3rd and 7th divisions. Only the 38th division was available for the actual invasion. There were several snafu's dealing with supply and an especially horrendous snafu due to not setting retirement allowed for a bombardment TF. In the end, however, PM was successfully invaded. The airfield seems to have been put out of action after the second bombardment (this bombardment TF had all my BBs) and kept out of action until the base was captured. Capturing a base with most of your opponent's bombers based there, unable to fly, can trully gut his chances of winning.

Playing as the US, these strategy will need to be modified because of the shorter range of U.S. fighters and the very long range of its level bombers. But this would seem to be a winning method for invading an enemy airbase.

[Luskan]

Far too complicated for me!
Also, I feel that a: a japanese player would need to use just about every ship at his disposal for such an invasion during May 42, (which will usually be running supply, troop transport elsewhere) and b: it is very risky to expose so much force to enemy carrier attack - who will have no fighters on LRCAP, and less fatigue.

Using those 1000 transports is too slow for me as well.

I just lost PM to Adm. Artic in my PBEM game, and he did it by hyper-building (every jap engineer on earth was used) Lae and GG into huge airbases (7 or 8), with loads of base support troops (which had to be stripped from elsewhere) and putting 100+ zeros and 60 bombers within a nice short striking distance.

Sure, he did have 6 or 7 flattops to my none (all at pearl), and the actualy fighting continued for almost two weeks due to the number of troops I ahd there to begin with, and the fact that after a week of LRCAP his zeros (LBA and naval) were just so exhausted that my dakotas and catalinas got through unescorted without any loss for weeks, flying in more and more troops (had plenty of supply to begin with). Even with the bombardments, the fighting (300 troops died on both sides just aout every turn for 20 turns, with 30000 troops on each side sort of thing) the engineering units at the base managed to get the airstrip operational enough to evacuate all the undamaged a/c (thank god! All my B17 squadrons etc) and even operate dakotas flying out useless units to Australia for a week before the base fell.

I am yet to invade PM in any games (although it is on the cards for Mike who lost both his carriers this morning to not scratching mine ) but if I did I would try and besiege the place with subs and mines and LRCAP to cut the supplies for a month or so first.