How would you defend an island in the 1920s-1940s? Pic related.

>>33293367
>How would you defend an island in the 1920s-1940s?

With ships.

Coastal submarines to deter ships and merchant submarines to bring in at least a trickle of supplies through a blockade

>>33293461
>Coastal submarines

And where exactly are these subs supposed to dock and replenish?

>>33293561
On your island

5,000 brainwashed japanese infantrymen with a fuckload of prep time

>>33293588
The Japs could have been a lot more effective on Okinawa if they had integrated communications between their hill bunker beyond a battalion level.

>>33293574

The one that's being blockaded and hit with naval gunfire and bombs?

Lol

>>33293621
Sometimes you lack the industrial capacity/money to challenge rule of the waves, but at the same time don't want to be invaded or otherwise lose sovereignty

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>>33293367
Successfully.

>>33293751
Torpedoes are ineffective against an island.

>>33293751
I feel like airbases would be fairly easily knocked out in this scenario

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>>33293621
Hard to bombard someone with a sinking ship.

Hard to launch aircraft from a sinking carrier.

>>33294732
To be fair, CVs are difficult prey for a slow, WW2 sub

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I would put one /k/ approved Sherman tank on each island. As we all know, Shermans were invincible supertanks that could wipe out thousands of nazis without inflicting any damage, as proven by a youtuber

>>33293367
Why not a sea-plane armed with torpedos?

>>33294816
Because Fort Drum proved to be extraordinarily resilient, and provided that you don't lose the mainland can be a lynchpin to defending chokepoints.

Torpedo bombers are also good, tho.

Minelayers and PT boats, probably something closer to German E-boats, which were a little more fuel efficient with their diesels

>>33293367
What budget do I have to play with?

It makes all the difference in the world between having infantrymen dig deep, massive cave systems and camouflaging rifle and machine gun positions and building major carrier battlegroups with hundreds of aircraft.

>>33294732

You're not going to be killing carriers and battleships with coastal subs.

>>33293666
>Sometimes you lack the industrial capacity/money

But...you don't. Not in this scenario.

OP asked how you'd defend an island, not how you'd defend it on a budget. Coastal subs are the dumbest way of defending an island.

>>33295897
Let's, for the sake of argument, assume that this hypothetical nation resembles the Solomon Island chain and had a similar level of development to Taiwan, so a population of 3 million in 1920 and perhaps 6 million in 1940.

GDP in 1920 in 1990 dollars of $2.5 million or so.

>>33296624
>GDP in 1920 in 1990 dollars of $2.5 million or so.

I know people who live in houses that cost more than that.

Good luck with your island defense I guess.

Coastal Guns

submarines

land-based light bombers

lots of AAA

>>33296653
The problem with beancounting for these scenarios is that it is often impossible between inflation, PPP, etc.

For example, Angus Madison estimated the average per capita Asian GDP (excl Japan) in 1913 at $750 (in 1990 USD), but without in depth knowledge of costs of military equipment in the 1920s, it's hard to give concrete answers about what is and is not on the table

>>33296624
So, enough to buy a half dozen mediocre fighters.
Okay then.

Kind of scraps my idea of ringing the island with a layer cake of arty and AA, with a core of P-38 interceptors and accurate radar guided AA for the bombers.

>>33296746
We should probably start with how little of our population we can keep under arms, and how little we can pay them.

However, to be fair, the likely hypothetical foe of Japan, wasn't particularly good at amphibious operations versus, say the US.

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like this

>>33296722

Yeah, that's why you're not supposed to get this autistic about dumb questions like this.

>>33296785

"ALL MUST VERK FOR ZE KOMMON GUT" (or some such sauce).

But yea, gotta set limits before proposing the scenario.

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>>33293367
boatsluts

in all seriousness

the idea of emplaced defenses was obsolete around WW2;

assuming this island needs to be defended, it's probably important; resupply hub? forward firebase?

Assuming it *needs* to be defended, you should be issued sufficient forces to do so, or there should be friendly naval traffic nearby (either heading to the front where you're the beachhead harbor, or just to resupply)

If this island isn't a resupply hub which would be frequented by other friendly military forces, or a strategic point on an contested front (which would also be frequented by other friendly military forces); why the fuck are you even defending it?

And even if you were ordered to; say some full retard scenario where you and the infantry squad you command must secure and defend one of those tiny ass islands off of hawaii in case god forbid some kind of sneaky japanese ship manages to land or something fuck if I know. If I was that sorry motherfucker in charge of that expedition, I wouldn't order any weapon emplacements, I'd want comfy living facilities, observation equipment, and radio equipment; if the location is not hotly contested, a covert observational force to call in the big guns is the best way to go.

mobile forces > fixed defenses

I think this hypothetical is really a scenario where you could see the significant importance of modern tactics versus historical ones even when equipped with the same type of equipment and munitions. the 20-40s really were kind of the turning point in the warfare materials available and the types of tactics and strategy that were possible with them.

>>33296895
Well, based on a level of militarization of modern day Afghanistan and Thailand, 5 active duty soldiers per capita seems reasonable.

So, in 1920, roughly 15k active (30k total) under arms and double that in 1940.

Since a Mauser 98 cost $28 in the 1930s, or $270-ish in 1990 USD, that's a good place to start with military needs.

I could see needing another 20k over the next 20 years to cope with population growth, since not everyone will get a rifle.

>>33297087
>assuming this island needs to be defended, it's probably important;

It seems to be more political, in the sense of a small country trying to preserve independence, rather than a far flung forward base of the US or Imperial Japan or something.

>>33296624
In which case, I'll be buying surplus weapons from WW1, instituting a nationwide marksmanship program, and digging massive underground tunnel systems, with concealed firing ports covering key approach avenues.

My standing army, if any, gets trained to a razor's edge in field craft, marksmanship, land navigation, anti-armor warfare and small unit tactics.

The idea would be for villagers to hold their village and the immediate surrounding countryside with the standing army harassing enemy forces in between strongpoints, and re-enforcing weak points.

Basically, rip off Japan's defense of Iwo Jima and the British Home Guard plans.

On the otherside, make defensive pacts with stronger nations, try to build some kind of spy network to penetrate potentially hostile nations. If it comes to war, invoke my treaties and have the spies commit acts of sabotage against the aggressor to hurt them and get favorable peace terms.

I'm not going to be able to buy enough good fighters or combat ships to defend a nation of islands.

>>33297165
>defending an island with rifles

lmfaoooo

Launch torpedos from the island.

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>>33297194
>>33297194
>political

Is it like cuba (From a ruskie perspective)?

IF SO; you'd be provided the resources needed.

Now that I've typed that response, I notice your non-'green' text. In that case; your ONLY bet really, assuming you're in any degree of control of the central leadership IS to ally with one of those superpowers.

If not; you're probably going to be shortly dominated foreign economic interests which operate at a scale orders of magnitude above yours, or will have been branded a rouge state target for liberation by a superpower.

There is NO market/playingfield for 'little fish' in the global pond. If you haven't chosen 'a side', and you're still alive; you're simply not big enough to be considered a serious player.

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>>33293367

>>33297165

Because you're not going to stand off a IJNLF with rifles. Let alone the USMC in the time era specified.

In fact, chances are you'd just piss both off JUST enough to thoroughly lay waste to said isle.

So presently you'd be speaking either English or Japanese.

>>33297367
That's an interesting question in itself. Would you rather be speaking English or Japanese? I feel like English is the obvious choice, be it the Bong or American variety, considering how Japan treated Taiwan, Manchuria, and Korea

>>33296746
>Kind of scraps my idea of ringing the island with a layer cake of arty and AA, with a core of P-38 interceptors and accurate radar guided AA for the bombers.

Tell us more

>>33293367
lots of nuggent mosins

>>33293367
Fixed coastal defense batteries were surprisingly effective in WWII, with the notable exception of the British guns at Singapore which for some retarded reason didn't have any HE rounds.

The other big advantage of coastal fortification is they lasted a lot longer then mobile force. Construction of Fort Maxam Gorky started in 1912 to protect Sevastopol and still posed a major problem for German forces in WWII. Similar coastal batteries outside of Leningrad defined the front lines as no German commander wanted to advance into pre-sighted battleship caliber artillery and the super-heavy guns used at Sevastopol were not available. German batteries in France were also successful, if to a lesser degree, in preventing Allied attack or forcing them to risk capital ships in distraction artillery duels while the ground forces launched their attacks.

Investment into coastal fortifications in the 1920s and 30s would not have been a bad idea, provided they remember to stock antiquate food and ammunition.

>>33298210
>Fixed coastal defense batteries were surprisingly effective in WWII, with the notable exception of the British guns at Singapore which for some retarded reason didn't have any HE rounds.
Fixed guns at Singapore would've been very effective for coastal defense except the Japs attacked by land.
As for them not having HE rounds, that's because they were anti-ship guns.
Retard kys.

>>33298249
Literally every other nation supplied its coastal defense guns with HE.

Note the examples included in the previous post of coastal defense guns using HE against ground forces.

>>33298293
There was no need to supply their 15 inch guns with HE. They had plenty of smaller guns and mortars that did the job better. Singapore didn't fall because they were short of guns with HE ammo. Even if you knew literally nothing about that particular episode of history, it's something you should've been able to infer if you had the minimal capacity to reason.

>>33298360
Sure there was a need, note the Japanese ground force that came and took the city.

While there were a number of other issues the British faced at Singapore it would have helped if they had more heavy artillery to use.

Would it have prevented the fall of the city? Probably not.
Was it a stupid oversight that resulted in a shorter resistance and less Japanese losses? Certainly.

Again, what I originally said is that the coastal defense batteries at Singapore, which were not supplied with HE, were notably less effective then those of other nations due to poor British planning. That statement remain true.

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>>33297087
>the idea of emplaced defenses was obsolete around WW2;
This is a stupid notion. Of course, everyone just repeats it because Patton said so.

Emplaced defenses aren't meant to keep the enemy out. They're meant to force the enemy to take on terms favorable to you and allowing you to defend it with the least amount of troops while keeping most of your forces in reserve for any attacks and breakthroughs.

This is why I laugh at those that say the Maginot line, and other fixed defenses "fail." The Maginot line had 80,000 men manning it, while in the interior of France there were 2 million backing them up.

>>33293367
with 360 degree -rotating small profile turrets mounting guns of various calibers for use against a range of targets (big, battleship's main armament -tier guns for shooting big & tough targets from afar & various smaller calibers for engaging smaller, more maneuverable targets at shorter ranges), minefields to deter landing operations, underwater nets to deter frogmen, torpedoboats mounting 20 to 40mm autocannons and machineguns to harass/destroy targets the turrets can't deal with, static large caliber anti-air guns in pits partially or completely below the island surface & smaller caliber anti-air guns both in static positions partially below surface as well as mounted on armoured vehicles & constantly moved around, with some always hidden out of sight so that enemy recon can't be certain how many guns there are on the island.

>>33298512
You are retarded. Having HE ammo for their 5 x 15 inch guns would have had zero effect. The decision to surrender Singapore was made based on the Japs complete domination of the mainland peninsula, without which Singapore could not be supplied with fucking water.

>>33300769
Maybe something smaller, like 8-9" guns. Battleship guns might be prohibitively expensive, and it might be better to deal with those asymmetrically with mines.

What about flak towers?

>>33293806
>"Why Sealion would never succeed" - the map

>>33300580
Out of curiosity, I looked up the garrison of Fort Drum as mentioned in the OP. Only 200 men. And it required a disproportionate amount of effort to knock out, even in its gimped form when the US was retaking the Phillipines

>>33293367
Missile silos and radar.

>>33293436
fpbp

>>33296016
In that case I defend it with a technologically advanced naval fleet that is three times the size of every other navy in the world combined.

>>33303540
just strip a turret or two from a battleship destined to be scrapped because of the Washington naval treaty & install them on the island (naturally camouflaging the turrets to make them harder targets), being able to return fire at battleships pouding your island from 20 miles away sounds like something I'd like to be able to do if necessary, regardless of the cost.

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>>33306280
pic related: a pair of Russian 12" guns installed on an island in Helsinki, Finland, part of Peter the Great's sea fortress (basically Finnish and Estonian coasts were fortified after the Russo-Japanese war in order to deny hostile fleets access to the Gulf of Finland, in the end the guns were used to deny Soviets access *out* of the gulf...)

>>33294802
Just stop memeing. It'd be easier to make stationary emplacements a la what the Germans did with panther turrets

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>>33307592
Finnish Navy took some T-55 turrets and put them on some islands as coastal defences, before that Finnish Navy had pic related (that's a 152mm gun)

>>33293367
Your big guns, tons of ack ack, fighters in protected bunkers with dive bom
The scrapped Dreadknought guns,mine fields, lots of ackack, protected bunkers for fighters and dive bombers and lots of prepared infantry positions.

>>33300580
So, what about a scenario where you lack strategic depth like on an island?

>>33293367
Electric eels

>>33300580
The Maginot line worked, it never had to fire a shot because no one dared to attack it, if the French had been better, or had extended the line to the coast, the Nazis would have had to go even more around it.