What factors make for a good invasion-landing beachhead?

Factual Questions
1

Off the top of my head, it seems a good invasion landing site (amphibious) needs the following:
[ul]
[li]Firm sand (not muddy or saggy, so as to not bog down the invading vehicles);[/li][li]A lack of major obstacles and big rocks;[/li][li]Nearby roads or paths that provide direct access to nearby objectives such as a town or broader network;[/li][li]A lack of hiding/sniping places for nearby defenders;[/li][li]Close proximity to invader nation, so as to enable direct supply/reinforcement routes by invader;[/li][li]A place where there isn’t much difference between high tide and low tide; (or is it *good *to have a big difference between tides?)[/li][li]A far distance from nearby enemy bases (“enemy” = the invaded country);[/li][/ul]
But at the same time, all of these elements are undesirable, too, in the sense that the enemy would also know perfectly well that they make for a good landing beachhead and hence would pay more attention to guarding such locations.

What other factors come into play?

2

Well it all depends. One of the normany jetties washed away, slowing the landing of provisions.

So you might want to use a protected bay. but this traps you in and limits the options,eg if this beach is no good, how about go to that beach ?

Room to build up forces on land, to reach minimum spearhead size. So that theres less drowing going on.
constricted area for the enemy pill boxes, bunkers to be in, so that pre-landing softening up is (more) effective. At Normandy, the softening up softened up some unused farmland only. Made big craters for the spearhead to dive off into. Seemed like a good idea at the time, but turned out to be a footshot .

The access to the beach should allow for a quick trip. No zig zag through enemy territotry or constrictions that reduce the flow rate.
Big tides tend to make a bigger slippery zone, and problems such as being washed back into the sea, so lesser tides are better,maybe, unless you use that area for landing the spearhead.

Waves can make the landing difficult, but it can keep the shore zone clear of enemy (eg enemy structures, mines, and so on )

However, its always an idea to land at the beach they aren’t expecting you to, but not the one you think they aren’t expecting you to, because they are expecting you to land at that one.

3

If you build up forces at sea, they turn into dark elves? :confused: :slight_smile:

4

What are you attacking? An island is a different kettle of fish, from a Continent where the enemy is backed up all the way to his home base. What is the air and sea scenario? Is the airspace and sea space contested? People look at Normandy landing and presume that it represents the ideal conditions. In reality, WW2 had amphibious landings of pretty much every stripe. From the German ones in Norway all the way up to Okinawa.

What factors you need, depend on the scenario you face.

5

No defenders opposing a landing could be useful.
Complete air superiority and an overabundant supply of air-droppable ordnance.

6

Reconnaissance.

7

The most important factor is that the beachhead be prior to about 1950 or be substantially undefended. or better yet, both.

The terrain issues the OP mentions are all valid. But pale in significance to the temporal issue. An amphibious assault of a well-defended beach in modern times would look about like a cavalry charge in late WWI. Fruitless and bloody. Very bloody.

8

The specific scenario I had in mind was China trying to invade

  1. Taiwan’s small offshore islands in the Taiwan Strait;

and

  1. Taiwan’s main island itself.

Although it was also a generalized question, for any other scenario too (i.e., what is the “Is this a good landing site” methodology used by Allies to assess Normandy or other places.)

9

Well. When you are talking about the small offshore islands, let’s assume China has air and naval superiority. Right now, they cannot achieve that, but it is not impossible. ‘All’ they have to do is stop loaning money to the USA, and develop domestic equivalents to the main weapons the USA uses. They have the industrial capacity to outproduce the U.S.A., and so in theory could be there in 10 years or so. (they probably won’t, it is not profitable or in accordance with their goals)

One thing they didn’t have in landing bombardments before is ground penetrating radar or airborne passive IR.

So the attackers could use bunker-buster bombs to kill all the defenders. If all bunkers are clearly visible on ground penetrating radar (they would be with current methods, though it might be possible to construct a ‘stealth’ bunker), and anyone on the surface is visible in IR, the attacking planes from China could just bomb the place until everyone is dead.

Once everyone is dead, send the Chinese admiral over in a launch and plant a flag on the crater strewn rubble of the islands.

I would assume the same could be done for the main islands, with the complication that if the Chinese plan to rule the place, and not just kill everyone, they’d need to pick a landing zone away from populated areas. That way they can treat anyone they see on IR as hostile, and again, destroy any cavities underground.

The main consideration for landing now would be missiles and artillery fired from long range. So they’d need some kind of anti-artillery, anti missile defenses to protect the forces as they land.

The sensible thing would probably be to use armored landing vehicles, similar to what the marines use today, and some kind of hovercraft packing missile defense, similar to what the marines use today.

All the defenders on the beach would be dead, though, which is why such vehicles would be practical.

10

ETA: agree w **SamuelA **as to the outlying islands. As to the Taiwanese main island:

First you prosecute a full-bore air/sea/space/cyber war between China and any allies vs. Taiwan and any allies. Once that’s fairly well along in the strategic “destroy the enemy homeland’s ability to fight” sense, *then * the currently-winning side can start to consider where on the currently-losing side’s territory it makes sense to establish the first beachhead.

Assuming of course the earlier stages of conflict don’t result in a political settlement to the war before the beachhead becomes necessary. Island nations have the inherent problem that they have little strategic depth to retreat into. Offsetting that is the difficulty of being invaded.

Absent allies on ether side China v Taiwan ends relatively quickly with Taiwanese capitulation or simple destruction in detail. Followed by unopposed landing of “peacekeeping” occupation troops from the mainland. Who perhaps will be harrowed by guerilla action for decades to come.

With allies it gets far more … interesting.

11

A couple of things to consider, using Normandy as an example:

Can you get to the beachhead? The Allies had to achieve naval and aerial superiority all the way out to the landing site to protect their invasion fleet. Failing to defend such a fleet from enemy forces could be disastrous, with men and material going straight to the bottom before they ever see enemy territory.

Can the enemy get to the beachhead? The allies used their aerial superiority to largely sweep the Luftwaffe away from the landing sites, which both served to hinder any direct aerial attacks, and also to make it more difficult for the Germans to ascertain the situation so they could mount an effective counterattack. Also, they attacked roads, bridges, and railways in the region, making it difficult for the Germans to get their forces to the landing areas quickly enough to prevent the Allies from massing their forces (one wave of troops is problematic. Fifteen waves that have had time to land and form up is substantially worse to deal with).

Does the enemy know where the beachhead is? In addition to the traditional use of airpower as a broom to keep troublesome eyes away and to interfere with communications, the Allies also employed information warfare, feeding the Germans bad information to have them chasing off in the wrong direction, and leaving them off-balance at the critical moment when the landings actually happened.

What is your goal in landing there? Dieppe was a minor raid to distract the Germans, cause some damage, and help refine Allied amphibious warfare doctrine. Normandy was a full-blown invasion to both liberate France and to pull the heat off of the Soviets. Incheon was a strike deep into the North Korean forces’ flank intended to break the back of the Communist offensive, thus relieving the forces defending the Pusan Perimeter. The amphibious invasion of Kuwait in 1991 was a full-blown feint meant to throw the Iraqi Army off balance and leave them vulnerable to the actual land invasion of Iraq from Saudi Arabia (which ultimately forced them to abandon Kuwait). What your goals are will dictate what resources you employ to achieve them (notably, in the Kuwait example, only naval forces were employed, with no landing forces at all, and everything else being sent across the Saudi Arabian desert to deliver the “Left Hook” instead).

Of course, your available resources will also dictate what goals you can pursue. In the spring of 1942, the Americans could hardly defend their own coastline from the German Navy, and were thus not in any position to send an invasion fleet to liberate France. By the spring of 1944, the situation regarding the American resources and priorities was entirely different.

12

All of your factors are absurd. The WW2 beach landings you saw in movies reflect unique situatios - the allies could land a bunch of men on a beach but couldn’t secure it with fire first because naval and air bombardment wasn’t accurate enough at the time, and thus some beacheads during the normandy invasion suffered higher than expected casualties. This had zero impact on the larger campaign. What the allies feared wasn’t that some beacha ssaults might get bogged down, they were worried that a large German armored counterattack could overwhelm the beachhead before they could be reinforced, and they couldn’t count on bombing alone to stop such an attack even with air superiority.

In a modern day scenario any beach defenders would have to be suicidal because everyone knows where the beach is and if the other guys are planning to go ashore on the beach then they already know where the defenders are and have enough firepower to kill anyone defending the beach before any of their own guys are anywhere near it. To plan anything otherwise would be suicidal for them, because if you can’t even kill everything within 2 miles of the beach then your invasion fleet would have been sent to the bottom by shore based anti-ship missiles long before they got anywhere near the landing site.

The idea that Taiwan could hold Jinmen or Matzu agains the mainland is absurd. Both of those islands are within rifle range of the mainland and would be reduced to a plowed field by artillery 3 minutes after hostilities start. What were the Taiwanese going to do? Launch their own amphibious counter-invasion of Shanghai? THe only reason they still hold them is because the communists literally did not have a navy or airforce while they did and the communists didn’t manage to build one in the ~1 year between the nationalists fleeing the mainland and the start of the Korean war.