Peter89 wrote: ↑
07 Jun 2020 09:25
Yes, because we've never known any cases where a well-fortified, unsuspecting fortress fell in WW2.
The Japanese, the Japanese
never tried to take a well defended position by amphibious assault. The closest two examples of a Japanese amphibious assault against a decently defended position we have are Kota Bharu and Wake.
At Wake, the Japanese ran several patrol boats (converted old destroyers) ashore to discharge about 2,500 troops total onto the island against about 500 defenders. The Japanese took heavy casualties but were able to overrun the defenses and take the island. That's a situation where they had complete air superiority, complete naval control off shore, and a roughly 5 to 1 numerical advantage in the attack.
At Kota Bharu, there were no coast defenses and the defending two Indian infantry brigades were spread over several miles of beach. The Japanese landed 5,200 troops. The Commonwealth defenses had some air power available but nothing but light bombers with small bombs available. The Japanese assault almost failed but they did succeed in getting ashore and staying. They took about 20% casualties in doing that. The defenders withdrew to new positions rather than were reinforced at the beachhead.
At Hawaii, the US after the second strike still had 87 aircraft serviceable on Oahu and another 79 that were repairable or otherwise being serviced. That included 52 P-36 and 40 fighters. The coast defenses were entirely intact.
https://cdsg.org/the-harbor-defenses-of ... or-hawaii/
There were two full triangular US Infantry divisions on the island and all total about 40,000 US troops available. Most of the Pacific Fleet was still intact.
To obtain surprise and get something close to the original results, the bulk of the Japanese invasion fleet would have to have remained several hundred miles off Oahu while the carrier planes struck. This means that for the invasion itself, the US will be alert and prepared.
Given the actual results of opposed Japanese amphibious assaults, and the assault on Oahu would definitely be opposed, the Japanese are not likely to succeed in staying ashore and being able to advance and take the island against the available defenses. The most likely outcome is the landing(s) fail with heavy casualties among the troops and even the shipping that is carrying them.
I guess you simply don't want to refer to my actual questions on this thread.
It is like: "the Germans can't take Eben Emael in time, so the whole Sichelschnitt plan is nuts". I have read well enough about the defenses of the HI here on this forum and in many other books, I never claimed that it was an easy nut to crack. I built up my case on the assumption that the HI were taken, which was not out of the realm of possibilities, as many high ranking officiers noted it, argued for it, etc. It was possible, and this is the What if section, meaning, we presume that the HI were taken.
If you want to continue to answer unasked questions and pour irrelevant data about the Pacific war, go ahead, it's nice to have some activity going on.
I hope you don't get offended. Peace.
I'm not offended, but I did try to answer your original premise using the best available data. Eben Emael is hardly representative of what the Japanese have to overcome. There are multiple forts spread over much of Oahu. These forts differ from Eben Emael dramatically in design because they are intended for a completely different purpose.
As you can see, the fortifications are extensive. They include guns from 16" to 3" in size in substantial numbers. The batteries are designed to survive a fight with opposing naval vessels and would be difficult to take. As I pointed out, similar defenses of Manila Harbor in the Philippines were not taken on by the Japanese until the very last in their conquest of the Philippines.
To even have a slim chance, the Japanese need an invasion force that would consist of most of their fleet escorting a half-dozen plus divisions with heavy artillery and tank support to even stand a chance. That pretty much precludes them doing much anywhere else. The biggest landings the Japanese actually made were a fraction of the size of the ones they'd have to make in Hawaii.
They'd need most of their fleet there to take on the remaining US Pacific fleet or keep them at bay if the US chose not to engage in a major surface battle. Japan's carriers carry sufficient munitions for about a half dozen full strikes. After that, the carriers would need replenishment, something that the Japanese didn't have a capacity for at sea.
The Japanese have to be able to bring their fleet to within miles of Oahu. The landing transports have to be able to get within a couple of miles of the beaches to be landed on, or less, to unload their troops into landing craft and boats that have very limited range. That means they have to be able to either take out the coast defenses or can withstand their fire until the troops get ashore and then overcome them.
That means the Japanese fleet will have to try and engage those defenses and suppress or knock them out, not an easy proposition. This is particularly true of those batteries like say, Battery Harlow (8 x 12" mortars) at Fort Ruger or Battery Williston at Fort Weaver in the middle of the island. The later was placed there because of its 360 degree field of fire and 48,000 yard range with its 16" barbette guns.
Attacking these defenses would be nothing like Eben Emael where the defenders had no intrinsic infantry available, and couldn't rely on support from adjacent fortresses. On Oahu, the US defense plan had infantry covering the coast defenses and the coast defenses could support each other. In the Philippines, US 12" coast defense mortars proved particularly devastating to the Japanese. Their big limitation was their range of only about 15,000 yards but had a 360 degree field of fire. But, if they could reach a target, they were not to taken lightly.