WI: SLCM/SLBM Systems Fielded in World War II

[Delta Force]

What if submarine-launched cruise missiles and ballistic missiles had been fielded during World War II? I know they wouldn't be useful for hitting specific targets, but could Germany and Japan have used such weapons to force the Allied powers to expend resources defending the coastlines of North and South America from attack? Might such attacks have encouraged neutral nations to remain neutral, especially those in South America?

In terms of systems, I am thinking of the Imperial Japanese Navy I-400 class submarine with V-1 cruise missiles, and other ships armed with V-1 missiles and V-2 rocket pods.

 

[Cook]

There was a proposal to launch V-1 missiles from the deck of U-boats, it didn’t even reach the experimental stage because of inter-service rivalry; V-1 was a Luftwaffe project and jealously guarded as such. One of the major problems with the V-1 was targeting: the guidance system depended on dead reckoning (flying for a pre-set time in a given direction) and it was critically important to know the exact location of the target in relation to the launch site. That’s not a problem when you’re launching from a fixed location on the coast of northern France, but it becomes significantly more problematic when your launch site is a U-boat; any small error in determining the position of the boat at launch is going to be magnified during flight. Another problem with dead reckoning is the effect wind will have on the bearing and flight speed, so it is essential to know the wind conditions between the launch site and target. The Luftwaffe sent long range aircraft out over the Atlantic to gather information for weather forecasting; after that ability was lost they relied heavily on BBC radio broadcasts to tell them the weather. A U-boat launch is going to struggle in respect to this too. The V-1 struggled to hit a target the size of London from a fixed point on the coast of France, from a U-boat things are going to be much worse.

With regard to the V-2, there does seem to have been a plan to build a sort of submarine raft, to be towed by a U-boat, to house a V-2. Given the problems with storing liquid oxygen (boom!), I don’t think these would ever have come to much. The issue of navigation is even worse with respect to the V-2 than the V-1, apart from the influence of winds.

As to countermeasures, the US navy instigated Operation Teardrop.

Hope that helps.

 

[Driftless]

How long would the subs of that era need to be surfaced to prep the V-1 for launch?

Also, how far out from the target? 200-250km?

 

[Delta Force]

How long would the subs of that era need to be surfaced to prep the V-1 for launch?

Also, how far out from the target? 200-250km?

The maximum range for the V-1 and V-2 was around 300 kilometers, and that would be if they were hugging the coastline. I imagine they would want to at least stay over the horizon, if not even further so that coastal observers wouldn't notice the missile launch and tell defensive forces exactly where to look.

 

[The Kiat]

How long would the subs of that era need to be surfaced to prep the V-1 for launch?

Also, how far out from the target? 200-250km?

How accurate would they be? Are you going to aim for Manhattan and end up landing in the middle of New Jersey?

 

[Delta Force]

How accurate would they be? Are you going to aim for Manhattan and end up landing in the middle of New Jersey?

It wouldn't be nearly that dramatic. The CEP (circular error probability, where 50% of missiles will land) was probably something in the range of a few kilometers.

 

[U.S David]

Germany doesn't need to kill anyone in New York or burn any buildings.

Just fire a few V-2 from a few U-Boats. This is going to scare the American Public. They won't feel safe after seeing Nazi rockets in the sky.

This will be a massive propaganda victory for the Nazis. It's going to backfire but still.

 

[Delta Force]

Germany doesn't need to kill anyone in New York or burn any buildings.

Just fire a few V-2 from a few U-Boats. This is going to scare the American Public. They won't feel safe after seeing Nazi rockets in the sky.

This will be a massive propaganda victory for the Nazis. It's going to backfire but still.

Or even more easily, they could fire them at Brazil, Cuba, Mexico, or any of the other states in the Americas that declared war on the Axis. That would spread Allied forces even thinner.

 

[Driftless]

It wouldn't be nearly that dramatic. The CEP (circular error probability, where 50% of missiles will land) was probably something in the range of a few kilometers.

IF they could get it launched before being spotted & attacked themselves, hitting anywhere in a large city like Washington, New York, Phildelphia, or Boston would scare the living bejeebers out of the locals, far out of proportion to the damage done. Washington & Philedlephia might be far enough from the coast to add too much degree of difficulty.

You could have the almost dieselpunk idea of a missile launching U-boat being attacked by a USN Blimp.

 

[dmg86]

I read that some of the ingredients of the fuel had a short life span and would not have lasted the trip across the ocean in any event.

 

[Apollo 20]

There would have been a lot of possible targets on both coasts. In the end, though, I doubt that any of this would have had much of an impact on the course of the war. The US ramps up ASW activities along the coasts and in the Gulf. A few cities probably get hit, but the damage and casualties would be minimal. Maybe some US aircraft manufacturing gets moved inland just in case.

The only real difference would be in how the home front remembers the war; American memories among coastal residents resemble those of the British a bit more.

The only way this could get really nasty would be if Hitler went off the deep end and used biological or chemical agents. In that case, the missile's CEP is less important -- and there's a whole lot more support for the Morgenthau plan after the war. If, somehow, this delays Allied victory, the Germans get nuked. Also, if there are chem or bio agents involved, there may be talk of relocating the national capital away from Washington for the duration of the war. Maybe it winds up in Pittsburgh or Cleveland.

 

[Driftless]

The only real difference would be in how the home front remembers the war; American memories among coastal residents resemble those of the British a bit more.

Wasn't there a quote from the Queen Mother about how she was happy in a way that Windsor Castle was hit by a German bomb (with modest damage)? Something to the effect that after that she felt that she could at least look the East Enders in the eye when visiting heavily damaged areas

 

[TFSmith121]

Think about this:

What if submarine-launched cruise missiles and ballistic missiles had been fielded during World War II? I know they wouldn't be useful for hitting specific targets, but could Germany and Japan have used such weapons to force the Allied powers to expend resources defending the coastlines of North and South America from attack? Might such attacks have encouraged neutral nations to remain neutral, especially those in South America?

In terms of systems, I am thinking of the Imperial Japanese Navy I-400 class submarine with V-1 cruise missiles, and other ships armed with V-1 missiles and V-2 rocket pods.

DE 635 and her sisters numbered more than 500, including the 90-odd Tacoma class PFs; add in destroyers, gunboats (PG), ocean-going and coastal cutters (WPG), patrol craft of various and sundry (PCE, PC, SC, PY, PYc, etc.), all those AMs and YMS, and the CVEs, and the AVs and AVPs and AVDs and their broods, and land-based naval air...and cryptology and traffic analysis, and etc ad infinitum. Much less the USN fleet submarines and USAAF land-based bombers...

Much less the RN, RCN, the RAF and allies in European waters, and the RCAF in the western hemisphere...

And when is this all supposed to happen? 1944? 1945?

I think the Germans and Japanese had a few other things to worry about by then...

And there's a reason the US and USSR spent most of the 1950s trying to figure out how to integrate guided missiles (using 1950s technology, not 1940s) with submarines - they don't go well together.

Best,

 

[Tallil2long]

For fun I once played with the idea of German sub-launched anti-ship missiles (using the very primitive IR- or radar-seeking capability just then being discovered) as a way to resuscitate the convoy war.

Utterly ASB, obviously. But I didn't know better back then.

Any way you look at it, a V1 or V-2 launching sub would still have to contend with the plethora of Allied anti sub ships, patrol aircraft with cm-wavelength radar, etc, not to mention the difficulties of transporting liquid-fueled rockets across the Atlantic (boom!), rocket unreliability (boom!) and inaccuracy. The best Germany might do is one or two successful strikes out of many uboats dispatched. No significant effect on the war. And the effort would have to come from other (probably more effective) uses of available resources.

Sadly, from my perspective. It'd be so much fun to write! (not so fun to live through a Nazi sub-launched blitz, obviously)

 

[Gannt the chartist]

Far more interesting would be if the RN had continued to develop the radio guided LARYNX in the 30's.

 

[eltf177]

The plan was for a V-2 to be carried in a huge cylinder towed behind a U-Boat. The cylinder was then flooded so the top would be sticking out of the water. The V-2 was then to be prepped and launched. Towing the cylinder would have slowed the U-Boat considerably, not to mention the huge sonar reflection. And prepping the V-2 would have been dangerous, and in rough seas probably impossible.

As mentioned earlier, the big problem is that by the time this technology is available it's far too late for the Axis to use it successfully as Allied defenses are too strong.

The other problem is that although the basics are there the technology to mesh them together is just too immature. The 1950's and 60's are littered with interesting projects that failed simply because existing technology was just not up to the task yet...

 

[RamscoopRaider]

Actually I think the US could probably deploy a sub launched cruise missile. Speed up the Bat (deployed in combat April 1945) and Loon (prototype ready October 1944, sub launched 1947 OTL) and you can put the seeker of the Bat on the chassis of the Loon and get a crude anti ship sub launched cruise missile. Or just deploy the unguided version of the Loon from subs at Japan

Make the Pacific war go worse for the US, and sub launched Loons at the Home islands is quite possible, potentially sub launched ASMs as well

 

[The Red]

Had Operation Downfall gone ahead it's quite possible that you would have seen the JB-2 being fired from Balao-class subs.

 

[Sior]

The plan was for a V-2 to be carried in a huge cylinder towed behind a U-Boat. The cylinder was then flooded so the top would be sticking out of the water. The V-2 was then to be prepped and launched. Towing the cylinder would have slowed the U-Boat considerably, not to mention the huge sonar reflection. And prepping the V-2 would have been dangerous, and in rough seas probably impossible.

As mentioned earlier, the big problem is that by the time this technology is available it's far too late for the Axis to use it successfully as Allied defenses are too strong.

The other problem is that although the basics are there the technology to mesh them together is just too immature. The 1950's and 60's are littered with interesting projects that failed simply because existing technology was just not up to the task yet...

 

[TFSmith121]

The "Platforms for work" sort of suggest the

The "Platforms for work" sort of suggest that turning an extremely complex mechanism from the horizontal (after a 3000 mile sea voyage across the North Atlantic at wave/periscope depth) was not envisaged as yielding a ready-to-use weapon at the end of the trip...

This thing makes the Russian "modified diesel-electric boats that have to surface to fire nuclear-tipped guided missiles from tubes that are so large they need an expanded conning tower to keep them within the hull volume of the submarine" designs look elegant...and tactically, the time required to make this happen just sort of suggests suicide mission.

Best,