Ultimate Challenge: Unternehmen Seelöwe

[Ariosto]

So the rough plan is as follows:

January
- Begin designing and construction of landing craft. To enter Kriegsmarine by August of 1940.
- Divert a significant number of resources from the Army to the Navy so as to speed production and commissioning.
- Begin importation of two thousand pound Aerial Torpedos from Whitehead.
- Start modifications on those Bf 110's that can carry two thousand pounds or more so they may be armed with an aerial torpedo.
- Begin construction of Naval Guns to be positioned on the Coast, of fifteen caliber or higher.

March
- Modifications for the Bf 110's should be finished, begin trials in the Baltic Sea.

May
- Fall Gleb begins.

June
- Fall Gleb ends.
- Air bases in Northern France and the Low Countries are repaired. The Luftwaffe begins attacks on the United Kingdom. Targets, in order of priority are: Air Bases, Radar Installations, Factories, Naval Bases
- Naval Bases to be intially staffed by the U-boat fleet, which will raid merchent fleets enroute to the United Kingdom.
- Construction begins on the Naval Gun Stations along the Strait of Dover.

July
- Luftwaffe Air Campaign against the United Kingdom continues throughout the month. Naval Bases not within the invasion zone are given increased priority.

August
- First landing craft begin coming off the production lines.
- Luftwaffe Air Campaign continues. Air Bases and Naval Bases are now given equal priority.

September
- Luftwaffe Air Campaign continues.
- Anti-Ship Bf 110's are deployed to Pas-de-Calais. Begin first combat sorties against the English Navy.
- Kriegsmarine sallies force to take position in the Straits of Dover, docking in Calais.
- Minefields are strung along the Eastern and Western edges of the Strait of Dover.

Late October
- Invasion begins.

Again, rough outline of what has so far been devised. However, if we are able to convince the Fuhrer that the Kreigsmarine must be reinforced with surface ships, and allocated additional resources, this will be the standing of our navy:

1 Aircraft Carrier
- 1 Graf Zeppelin Class

4 Battleships
- 2 Bismarck Class
- 2 Scharnhorst Class

2 Pre-Dreadnaughts
- 2 Deustchland Class

8 Heavy Cruisers
- 3 Deutschland Class
- 5 Admiral Hipper Class

6 Light Cruisers
- 1 Emden Class
- 3 K Class
- 2 Leipzig

26 Destroyers
- 4 Zerstorer 1934 Class
- 12 Zerstorer 1934A Class
- 6 Zerstorer 1936 Class
- 4 Zerstorer 1936A Class

23 Torpedoboats
- 6 Type 23 Class
- 5 Type 24 Class
- 12 Type 1935 Class

8 Minelayers

89 R-Boats
- 16 R-1 Class
- 8 R-17 Class
- 16 R-25 Class
- 45 R-41 Class

~25 E-boats

10 Fleet Escorts ("Flottenbegleiter")

Numerous Landing Craft, Marinefährprahm class


The problem we encounter with the Graf Zeppelin, however, is who is going to have control of the carrier based aircraft. The Luftwaffe or the Kriegsmarine? I would prefer the latter, but it is not up to me. Therefore, it is questionable whether we should even expend resources on the Graf Zeppelin, unless we decide to use it as a massive supply ship. Even then, its value is questionable.

 

[jlckansas]

Here is the cross channel guns site on wikipedia. Checked most against the RR artillary board and some coast defense sites that I know of so it is pretty accurate.
http://en.wikipedia.org/wiki/Cross-Channel_guns_in_the_Second_World_War

On the accuracy of the guns, attacking fast moving naval combat vessels, not good accuracy, but against slow moving transports and landing craft, well a close miss is gonna do some damage. Plus the UK can bring up other RR guns to fire on them at long range and be accurate due to the fact that it would be on known ground.

 

[Ariosto]

Here is the cross channel guns site on wikipedia. Checked most against the RR artillary board and some coast defense sites that I know of so it is pretty accurate.
http://en.wikipedia.org/wiki/Cross-Channel_guns_in_the_Second_World_War

On the accuracy of the guns, attacking fast moving naval combat vessels, not good accuracy, but against slow moving transports and landing craft, well a close miss is gonna do some damage. Plus the UK can bring up other RR guns to fire on them at long range and be accurate due to the fact that it would be on known ground.

Krupp K5 Railway Guns could be used as mobile Gun Stations in this case, along with the stationary Naval Gun Stations.

 

[ChaosNDiscord]

Bombing the southern ports will only help the first wave. All the RN need to do is station their fleet in Rosyth and send it down in the event of an invasion. This would mean that once the first wave is across, they are trapped with no chance of supply. Also if the ports are bombed to bits, how will the heavy armour get across?

This brings me on to another point. Landing craft. How on earth are we going to get enough landing craft for hundreds of thousdands of soldiers in less than a year. Any timescale over this and the invasion is out of the question anyway. Seriously, what will you bring them across on? River barges?

The scheme is doomed.

Which is why I advocate the indirect approach. Starve the English out. Destroy the ports, ships, everything. No need for invasion, since the British will simply wither away.

 

[redcoatT]

Which is why I advocate the indirect approach. Starve the English out. Destroy the ports, ships, everything. No need for invasion, since the British will simply wither away.

You mean like the Germans tried to do in real life...... and failed

 

[redcoatT]

Krupp K5 Railway Guns could be used as mobile Gun Stations in this case, along with the stationary Naval Gun Stations.

and how good are these guns at night

 

[redcoatT]

Late October
- Invasion begins.

No, it doesn't.
Nobody who understands the conditions needed for a successful invasion across the Channel would ever plan to start at such a late time of year, the weather is far too unpredictable.
In 1940 both the British and Germans knew that the latest time an invasion was possible was late September.

 

[jlckansas]

and how good are these guns at night

Better than an airplane at this stage of the war. In an attack on ships at sea only the target is moving and you are attacking from a known point to a known moving point. On land its the same as daylight. Artillery fire from any caliber weapon is not degraded by firing at night. As to the ships in the channel you had search lights and spotters, ground and air, that would see the splashes in relation to the target to make corrections. On land even easier, you are still firing from a known point to a stationary known point so you know the range to begin with and can walk them in just like a standard call for fire. Just the big guns are not firing as fast as say 105s or 155s.

 

[Don Lardo]

Better than an airplane at this stage of the war.

Which, of course, is why Germany used coastal artillery to routinely attack shipping in the Channel.... ... oh wait a minute... ... they didn't. They used aircraft, mines, and E-boats to attack shipping in the Channel because I guess they were too stupid to figure this all out. Those silly Nazis, they could have used coastal guns all that time!

Artillery fire from any caliber weapon is not degraded by firing at night.

Aiming artillery fire most certainly is and I'll let you talk to the Allied survivors of the various Solomon Islands battles against the IJN to learn about that.

As to the ships in the channel you had search lights...

A searchlight. With a twenty mile range. Sure, whatever.

... and spotters, ground and air, that would see the splashes in relation to the target to make corrections.

Sure they will. Even the IJN's famous corps of night spotters didn't pick out shell splashes. They needed floatplane flares, big slices of the moon, and other tricks too. Just as I wrote up-thread, this little roleplaying farces is doing nothing but make those taking seriously look like fools.

 

[Mostlyharmless]

Oh dear! I started writing this about 12 hours ago and find that I cannot keep up with all the new ideas except that I have added the Bf-110 suggestion.

I hereby submit my request to be reassigned to a combat command. This so-called "plan" is fruitless and will never achieve a workable solution to the problem. The might of the Royal Navy is simply too great. We might as well speak of digging a giant tunnel under the English Channel. Perhaps if we had started planning in 1936, we could have achieved something. With the time at our disposal, though, the task is simply impossible.

I am not going to ask for reassignment to a combat command because I have a strong aversion to loud noises and fast moving pieces of metal. Also I like to spend my evenings playing bridge and find that this is difficult when living in foxholes. As a bridge player, I know that on some occasions it only possible for the contract to succeed if the cards are distributed in a particular way. When the contract can only succeed if the player on my right has a king doubleton in hearts, it is necessary to calculate a line of play starting from the assumption that he has the doubleton and thus, for example, that the player to my left has four hearts. If I also believe, like both Beck and Hitler, that the alliance with Stalin will not last, I may decide that the war must be won in 1940 or it will be lost. Thus I will assume that the attack on France will gain a quick and decisive success. From this assumption, it is obvious Britain will be most vulnerable to invasion in the week following a French armistice. Thus it is necessary that a invasion can be launched in that window of opportunity and also that every effort is made to destroy British forces in France before they can withdraw.

If I had been employed to make these plans from 3rd September 1939, I would have been confident that enough landing craft could be designed and built http://www.german-navy.de/kriegsmarine/ships/landingcrafts/index.html (the likely time scale can be seen from http://en.wikipedia.org/wiki/Siebel_ferry which reports that 25 had been produced by the end of September 1940 after the design process started in July). At the other end of the size scale, it should be possible to use liners such as Bremen, Europa, Potsdam, Gneisenau and several others which could certainly transport enough troops but may need lighters to unload. We can also increase the production of transport aircraft and perhaps, if starting from September 1939, produce the Me 321 and Me 323 to allow us to transport Pzkw IIs at least by air. Ideally, we should build something like the Marder II, http://en.wikipedia.org/wiki/Marder_II, to handle possible attacks by British Matildas. Ah but the PAK39 is not ready for service I hear shouted. True but we can use 7.5 cm FK 38, http://en.wikipedia.org/wiki/7.5_cm_FK_38, which fortunately is being produced for Brazil and, with a new armour piercing round, is better than anything else available except for the 88.

Soon somebody is going to say “Where are all these resources going to come from? Tooze shows that the German economy was fully mobilized ...etc.” However, we have decided to win the war in 1940. Thus synthetic fuel plants, completion of the new Volkswagen plant, http://en.wikipedia.org/wiki/Volkswagen, which produced its first Kubelwagen in 1940 but was not complete until 1941, the huge FMO-Flugmotorenwerke Ost factory for the Jumo 222 and even the Nibelungen-Werke tank factory are unnecessary, freeing up resources for perhaps a 50% rise in the 1940 weapon production, which we will certainly need.

There are naturally some problems, essentially coming down to the Royal Navy and the RAF. The obvious way of dealing with the RAF is more Bf-109s (possible), more pilots (difficult) and drop tanks, ideally made of paper (easy). We should also start practising directing fighters from radar equipped ships (easy if LW and KM co-operate). Getting anti-aircraft guns positioned shortly after the landing may be critical for being able to unload the ships.

The RN is even more difficult! It is probably impossible to speed up Bismarck's completion and work up for July 1940 and it may also be difficult to complete any other extra cruisers or destroyers although we should be able to move forward Admiral Scheer's refit so that it can leave dock well before 31st July 1940. Thus we need to reduce the number of ships sunk and damaged up to 1st July 1940. Again notice that we are planning to win the war in 1940. Thus the possession of Norway is desirable but not critical. It is actually in our favour if there is a British Army occupying Narvik on 1st July 1940 because it cannot defend Britain. We can either scrap the attack on Norway and Denmark completely or minimize the risks by only landing in the South of Norway (the Narvik destroyer force needed to refuel before returning and their tanker was sunk) and avoiding dangerous waters such as the Droebak Narrows. The advantage of such an operation would be that the Luftwaffe can attack the RN over several weeks and thus gain experience in air attack on warships. Of course, without Norway we will have opportunities off Dunkirk. However, either way we are clearly going to depend on aircraft to defeat the RN.

We have an excellent dive bomber in the Ju 87. The only problem is that we need to train a large force in anti-shipping operations. The He 111 proved to be a good torpedo bomber and the Ju 88 was faster if not quite so forgiving. It has been suggested that the Bf-110 would have also been effective and the Bf 110E-1 later did have racks that could have carried two (!!) torpedoes, so the ground clearance was adequate although I have never heard of a torpedo being carried. The problems are getting useful torpedoes and training the crews. The German air launched torpedoes in 1940 made the American equipment look very good (i.e. it was useless). The Italians were developing good torpedoes but had hardly put them into production until the middle of 1940. The Japanese air launched 45 cm Type 91 Mod 1 had been in production for many years but was being replaced by the mod 2 with anti-roll stabilizers in 1940. Nevertheless, I think that it was a mod 1 that first hit Prince of Wales, so these may have been the best designs to copy if they can be bought. Japan might be interested in tools for making fuel injectors and in radar if these can be sent, perhaps on Italian warships to East Africa and on a Japanese cruiser to Japan. Note that as we intend to win the war in 1940, we are not worried by our secret technologies being revealed. Hopefully, by combining all the designs, something useful can be produced in time. Training in torpedo bombing may be even harder to organise. The Italians have no torpedo bombers in service, the Japanese may not be helpful after the Molotov-Ribbentrop Pact and the Baltic is frozen in winter. Thus torpedo bomber training will probably start in about April 1940 and we will need considerable mental strength to keep 100-200 bombers out of the critical battles being fought during April-June 1940!

Finally, we are going to have luck (especially if in a moment of paranoia we change the Enigma rotors after the Battle of France). Even if we cannot persuade the Italians to attack Malta at the proper moment, the British will be enmeshed in Operation Catapult at the moment that we strike (naturally after a week of attacks on all British naval bases that can be covered by Bf-109s with drop tanks).

 

[Ariosto]

Very well then, the operation is pulled back to occur in Late September. However, that reduces the number of landing craft available, which means that we are likely reduced to those two beaches that I had highlighted in the previous map, rather than additional ones to the west.

As for searchlights, there is only 21 miles of water between Dover and Calais. So if the maximum range of the searchlight is 20 miles, well, that means that almost everything except a portion of the English Coast is not lit up. Also coastal guns (Krupp K5) were used against shipping in the Channel, successfully, but they were later employed to other theaters where they were deemed more important. K5's will be built in larger numbers and be the armanent of these Naval Gun Stations.

The Battleships Bismarck and Tirpitz are definately going to be ready for deployment by the time required to sortie to Calais, but only if additional resources are diverted to aid in their commissioning. If not, the Tirpitz may or may not be ready to sail. The rest should not have any major problems.

Now I have been reading several documents on these units called the Fallschirmjäger, men who are dropped behind enemy lines from transport aircraft. If we could make a landing Northwest of Dover, we would be able to surround the city and more swiftly capture it. However, it is their armanents that I am worried about. Immediately after the jump, they only have a knife and a pistol on their person. The main arms are dropped in seperate crates along with the men. Is there a way that we can drop these men with at least a MP 40? Granted, these are some of the best soldiers in the Reich, but there is only so much you can do with a pistol.

 

[redcoatT]

As for searchlights, there is only 21 miles of water between Dover and Calais. So if the maximum range of the searchlight is 20 miles, l.

The maximum detection range of the most powerful German searchlight in 1940 was around 8 kilometers.

 

[Teleology]

If war with the Soviets hasn't broken out yet, is there anything they can bring to the table? They can have Scotland, Ireland, Northumbria, the Midlands, Wales.

Occupying Cornwall and England will be more than sufficient for Germany.

 

[jlckansas]

Which, of course, is why Germany used coastal artillery to routinely attack shipping in the Channel.... ... oh wait a minute... ... they didn't. They used aircraft, mines, and E-boats to attack shipping in the Channel because I guess they were too stupid to figure this all out. Those silly Nazis, they could have used coastal guns all that time! Aiming artillery fire most certainly is and I'll let you talk to the Allied survivors of the various Solomon Islands battles against the IJN to learn about that. A searchlight. With a twenty mile range. Sure, whatever. Sure they will. Even the IJN's famous corps of night spotters didn't pick out shell splashes. They needed floatplane flares, big slices of the moon, and other tricks too. Just as I wrote up-thread, this little roleplaying farces is doing nothing but make those taking seriously look like fools.

Lets tackle these one at at time.

Germany did use their coastal arty to attack shipping and the Dover area all the time they occupied the Pas De Calais area. Plus when the Peenemunde arrow shells were used they struck, IIRC from Ian Hoggs German Artillery book, up to 30 to 40 miles inland in southeast England when fired from the Pas De Calais guns. In this case they would be bombarding the English Coast defenses, known positions at known ranges both day and night in all weather. Also on the coastal guns, remember Point Du Hoc? the whole reason the rangers attacked it was to knock out the coastal guns which would be able to attack the fleet on Omaha beach.

As to the degradation and aiming, its different firing a large cannon greater than say 11 or 12 inches from land then a ship based weapon. You are firing from a stable platform, the land, to a fixed target, the English defensive areas along the beaches, at a known range that you would start firing at during the daylight to spot your shots.

As to the English firing back. Again firing from a known positions to a known area in the channel. You could fire ranging shots during the daytime to get it zeroed in. The invasion fleet would be doing at the most 10 to 15 knots cross channel. As to the searchlights yes you have a range factor with them but you would also have the larger caliber weapons firing flares into the area to help spot the invasion fleet. In addition the fleet would not be zigzagging individually but as a group so your attacking an area target. With the light construction of the invasion fleet a near miss would be as good as a hit.

This is a mature science for the time unlike the aircraft vs ship attacks. Large caliber weapons on land were tested all the time, including the naval ones that were meant to be mounted on battleships. The gunnery tables were worked out by both science and practice from before WWI.

 

[Don Lardo]

Lets tackle these one at at time.

No, let's not. Quibbling over details will only obscure the fact that you and the rest are engaged in a fantasy here.

Nothing being proposed in this thread hasn't been suggested hundreds times before and found wholly lacking. Actual military professionals, both German and Allied, both at the time and later, with more knowledge than you or I ever will have looked at this operation and concluded it was insane to even attempt it.

A Sealion in 1940 with only 6 months planning and construction is suicide. That's the unanimous opinion of actual military professionals and not the internet fantasies of historical hobbyists.

Nothing, as in nothing, you "roleplayers" dredge up is going to make Sealion work. Not oodles of coastal artillery, not magical spotlights, and most certainly not German guns on the Pas de Calais firing over twenty miles away at targets on English invasion beaches.

Sure, the Nazi pulled a few technical stunts like those mentioned in Hogg's book. However, if you think those shells were aimed with anything resembling accuracy let me suggest you sit in the foxhole calling in the next barrage.

This thread is nonsense and those seriously participating in it are wasting their time.

 

[juanml82]

Mein Fuhrer, as my previous proposal of volunteering to begin diplomatic agreements with Sweden, including being posted there for years if required, was rejected I come with a new plan. However, I must warn you, you are not going to like it.

First, I understand further plans for the Reich require the war with the UK to be over within a year or two.
Second, achieving in southern England and perhaps the British Midlands is within the possibilities of the Luftwaffe. Holding the Royal Navy is not within the possibilities of the Kriegsmarine and, in the event of invasion, our bombers will also be required to support the invasion, limiting their availability to damage the British warships.
Finally, the goal is to achieve a ceasefire with the UK, not necessarily to invade and occupy them, although that would certainly prove an asset to the Reich. In summary, we need to break either their will or their ability to fight.

Plan A begins right after the fall of France. We begin to set up an invasion force with the resources available. Seemingly in preparations for that, the Luftwaffe needs to destroy the RAF as a fighting force. In doing so, special attention must be paid into bombing and destroying their bombers as well as their fighters. Once they are against the ropes, the British will need to prioritize fighters, since are cheaper than bombers and urgently needed. Their bomber arm will not receive enough replacements and pilots will be training in day fighter tactics. Their bombers will also be based further north. We do count on the Me110 to escort our bombers beyond the Me109 range - still, producing drop tanks for the Me109s is a sensible idea. Once the British Bomber Command has been significantly damaged - and note I say significantly damaged, we won't wipe it out completely - we use gas.
We can use it in a limited, demonstration, attack against a small settlement while accompanied by peace overtures in the form of an ultimatum to break their will to fight. Or we can use it in one large scale attack against their major cities. The goal here is to break both their will and ability to fight, as much as possible. Make no mistakes though. They will hurt us with gas as well, and they will hurt us badly. We need to make sure their bombers are limited because of this and we need to make sure they think they'll take the worst of the exchange. In that situation, Chamberlain will accept peace. This plan, however, will cause great damage to the Reich. I do not recommend it.

My second recommendation also uses chemical agents. But it does in support of the invasion. We prepare for it. The night before launching it, our bombers launch a massive chemical strike against the major RN anchorages. The objective is to kill or temporarily incapacitate as many of their sailors as possible. With the RN undermanned, our first wave can have a chance. And, with our invasion underway, the RAF will need their bombers to stop it, which will reduce the number of planes they can use to attack our cities with gas. We will need to provide our troops with chemical gear, as the British will most likely use gas in combat as well. And specially, once inland, we need to attack as fast and as deep as possible, as we might not be able to resupply our invasion forces. The threat of using gas, in combat, near their cities is likely break their will to fight, as well, should we accept to withdraw from the British isles in exchange for peace.

All other alternatives available to us lead to a disaster while trying to invade, or a protracted war with the British Empire, which we should avoid.

 

[cbr]

Wow, you've managed to move from alternate history to Lalaland within 3 pages, that must be some kind of record for a non-ASB thread.

An invasion of Britain in october? Do you know what you are saying? There is a reason the German High Command had a timelimit on september, because even that would be risky, but still marginally feasable. A channel crossing in october is fantasy.

Also it's amusing you think they'd start preparing to invade Britain in January when at that time they didn't even know how long the invasion of France would take. The idea that Goering would part with many of his planes to be retrofitted and tested for torpedo and anti-shipping missions before the fall of France is insanity.

I'm not even going to comment on the fairytale of costal artillery with its accurate 20 mile fire or the magical searchlights.

 

[The Red]

If I may give some input, I would advise the best way to repulse the Royal Navy would be to load up Heinkel He 111's full of explosives and smash them into ships.

 

[Astrodragon]

Mein Fuhrer, as my previous proposal of volunteering to begin diplomatic agreements with Sweden, including being posted there for years if required, was rejected I come with a new plan. However, I must warn you, you are not going to like it.

First, I understand further plans for the Reich require the war with the UK to be over within a year or two.
Second, achieving in southern England and perhaps the British Midlands is within the possibilities of the Luftwaffe. Holding the Royal Navy is not within the possibilities of the Kriegsmarine and, in the event of invasion, our bombers will also be required to support the invasion, limiting their availability to damage the British warships.
Finally, the goal is to achieve a ceasefire with the UK, not necessarily to invade and occupy them, although that would certainly prove an asset to the Reich. In summary, we need to break either their will or their ability to fight.

Plan A begins right after the fall of France. We begin to set up an invasion force with the resources available. Seemingly in preparations for that, the Luftwaffe needs to destroy the RAF as a fighting force. In doing so, special attention must be paid into bombing and destroying their bombers as well as their fighters. Once they are against the ropes, the British will need to prioritize fighters, since are cheaper than bombers and urgently needed. Their bomber arm will not receive enough replacements and pilots will be training in day fighter tactics. Their bombers will also be based further north. We do count on the Me110 to escort our bombers beyond the Me109 range - still, producing drop tanks for the Me109s is a sensible idea. Once the British Bomber Command has been significantly damaged - and note I say significantly damaged, we won't wipe it out completely - we use gas.
We can use it in a limited, demonstration, attack against a small settlement while accompanied by peace overtures in the form of an ultimatum to break their will to fight. Or we can use it in one large scale attack against their major cities. The goal here is to break both their will and ability to fight, as much as possible. Make no mistakes though. They will hurt us with gas as well, and they will hurt us badly. We need to make sure their bombers are limited because of this and we need to make sure they think they'll take the worst of the exchange. In that situation, Chamberlain will accept peace. This plan, however, will cause great damage to the Reich. I do not recommend it.

My second recommendation also uses chemical agents. But it does in support of the invasion. We prepare for it. The night before launching it, our bombers launch a massive chemical strike against the major RN anchorages. The objective is to kill or temporarily incapacitate as many of their sailors as possible. With the RN undermanned, our first wave can have a chance. And, with our invasion underway, the RAF will need their bombers to stop it, which will reduce the number of planes they can use to attack our cities with gas. We will need to provide our troops with chemical gear, as the British will most likely use gas in combat as well. And specially, once inland, we need to attack as fast and as deep as possible, as we might not be able to resupply our invasion forces. The threat of using gas, in combat, near their cities is likely break their will to fight, as well, should we accept to withdraw from the British isles in exchange for peace.

All other alternatives available to us lead to a disaster while trying to invade, or a protracted war with the British Empire, which we should avoid.

Oh my!!!
The Fuhrer is going to like it even less when the reaction of the British to being gassed is to drop Anthrax all over Germany....!!!

 

[Mostlyharmless]

Oh my!!!
The Fuhrer is going to like it even less when the reaction of the British to being gassed is to drop Anthrax all over Germany....!!!

Fortunately, the British only started tests in 1941 http://www.wnd.com/?pageId=11567 and equally fortunately the German's only started tablun production from 1942 http://en.wikipedia.org/wiki/Tabun_(nerve_agent). Thus it is back to WW1 agents and protection of ships against these had been considered (and perhaps practised?). The ships most obviously vulnerable would have been USN aircraft carriers with open hangars, which was one argument used for British and Japanese closed hangars. Most anti-aircraft guns and all destroyer armament would suffer from a persistent agent but there is the nice feature of ships that they move out of gas clouds quite quickly when at sea.