Most effective "possible" WWII weapon at sinking merchantmen?

CalBear

Moderator
Donor
Monthly Donor
Submarines in a walk. Nothing else comes even close.

Had the KM had a reasonable number of boats (the total force was only 57 boats, only 23 were capable of operation into the Atlantic shipping lanes) the Reich could have done vastly more damage. The Reich would not have been able to force a British Surrender, but the issue would have been very close. The U-boats sank 14 MILLION tons of shipping. Still, the KM failed, mainly because the Allies, primarily the U.S., constructed 38 million tons of merchant tonnage, built hundreds of specialized escorts. broke the Reich's codes, and invented a type of warfare that had never before been attempted.

In the Pacific the result was dramatically different. The USN did starve Japan while sinking three of every five merchant ships, of any size, that the Japanese operated during the entire war.

The second best weapon was mining, both submarine deployed and air deployed. the U.S. mining campaign effectively made the Japanese Inland Sea a "no go" zone and made the waters between Japan and Korea a death trap.

Aircraft are a nice addition, especially if you can get them into restricted waters that the enemy has to transit, but they are far less capable in the open sea (too much sea, too few aircraft, limited operational window) and are much more vulnerable to the defensive armament that can reasonably be added to a merchant vessel without compromising its primary function. Among aircraft weapons the best option, by far, is the air dropped torpedo. Unlike warships, which have the speed and maneuverability to often avoid the deployed weapon, merchant ships (in WW II generally possessed with top speeds of 10-12 knots) are unable to dodge a torpedo. One torpedo was sufficient to sink or cripple almost any merchant vessel used by any nation throughout the war.
 
Wait, you were actually serious about 40mm/.50 cals in turrets, and that the turret would only weight 2,000 lbs?
Yep. The figures you are providing I believe are for the OTL naval version of the weapons, which has some other factor from an airborn weapon.
If I have my numbers rigth, the naval version had a range exceeding 7,000 meters, while I need something just a we bit more than 1,000 meters. The naval version needed to propel it's rounds up, while mine will not.
to keep with the originally posited turret weight, lets consider. The M2 (like the ones I dealt with in the army) < 100 lbs, but lets call it 100 lbs. The turret say 1,000 lbs. We now have 800 lbs for a pair of 40mm aircraft mounted autocannons, so a max of 400 lbs each. What do you folks think? Can a 40mm autocannon be built, have say 1,200 yard range, with enough hitting power to penetrate a merchantmens hull from 1,000 yards out and 1,000 feet up be developed that fits this weight limit? Off the top of my head, I can say that I can definately get the range, but not sure about the penatrating power, I just plain don't know on this one.

A 40mm Bofors (to get you the 2lb shell) weighs 1,000 lbs per gun, and a naval twin mounting gets you another 10-15,000 lbs, 2,000 lbs for another 500 rounds per gun. You're missing a zero there just for the mounting alone, let alone the reinforcement the airframe will require to cope with the recoil.
Don't need the naval version, as I dont need the 7,000 + meter range nor ability to fire UP, as I will be firing from above, thus need much less of a cannon.

So far as rounds penetrating the water goes, of course some of them will penetrate quite some distance. The problem is that they are very rapidly losing velocity, and depending on the angle a number will ricochet off the surface. Remember that the ships aren't made of paper-thin material like aircraft - 1" thick plates are not uncommon, not from any form of armour but simply because they need the structural strength to stay together.
The penetration power could be a show stopper, if the lighter airborn cannon cannot pierce the hull from 1,000 yards.

Finally, your attack profile seems explicitly designed to do several things, none of them good:
I see. Well, lets take this one step at a time, shall we?
Ensure the guns are installed in the heaviest possible manner, minimising range and payload.
The lighter mounting of fixed weapons comes at a cost I don't want to have to pay.

Maximising the amount of time your aircraft stays over the target, ensuring that any gunners have plenty of time left to shoot at it. Note also that you are presenting a broadside on target to any AA gunners.
I do want to give my gunner the most time I can to hit the target, true. This likely makes his fire more accurate, and thus is more effective. Although I should probably point out, my attack profile will never actually have me 'over the target', but rather 1,000 yards out.

Making your gunner's aiming job hard, by ensuring that he is always firing deflection shots against a target at a continually changing angle. That obviates any chance you have to get decent concentration of fire against a single spot.
First, my attack profile has me moving a say 200 miles an hour, on a paralelle course, and while this will always be a deflection shot, the change in range is going to be slower and much less than a conventional, charge right in attack. Secondly, I don't want multiple hits in the same area, but multiple hits well seperated from each other.

Ensuring you're in trouble if bounced by fighters - bombs and torpedoes can be jettisoned at need, a turret cannot be.
If your getting bounced by fighter, your already in trouble.:p
:D

Now for the rebuttal::cool:

By mounting the weapons in a light weight, but fixed mounting I doom myself to the following disadvantages.
1) I am forced to aim my plane at the target.
2) I am forcing the fellow flying the plane to double as my gunner. This both distracts him from bringing accurate fire to bear, and reduces the missions effectiveness overall.
3) I am forcing my planes to get much closer to the target than 1,000 yards. All other things being equal, shorter ranges mean more accuracy from the defenders AA.

Advantagious trade offs from heavier mountings.
1) With a turret mounted armament, my plane does not have to be aimed at the target ship, but can attack in a wide varity of attack profiles.
2) By allowing my gunner to concentrate on the task at hand, I will achieve better accuracy, and this is needed for the very specific targeting I am attempting, while the 'point at the target' attack profile really cannot deliver this sort of attack at all.:eek:
3) Maintaing my distance, will have a very drastic effect on the effectiveness of defensive AA fire, far more that most folks would suspect. It isn't simply a matter of being farther away, it is far more than that. An expert defensive AA gunner would have quite a bit harder time hitting a plane using my attack profile that the OTL one, and an inexperienced gunner is going to need a great deal of luck. Can anyone guess why?

Next point, the time on target, and broadside on aspect.
1) While giving the enemy a larger target seems like a bad idea, here are some things to consider here. My posited aircraft will be coming in around say 200 miles per hour (maybe more if we feel the need to waste the fuel), and this will limit the time My gunner has to bring his weapons to bear. Maintaining a constant bearing while on the approach, allows him to adjust in a single dimension, rather than two (range and altitude), which will also serve to increase his accuracy. This is not possible with the fixed mountings.

And finally, the big tomale'.
By keeping my distance from the target, I reduce the accuracy of their AA fire. It has been repetadly pointed out that my attack profile with cause my planes gunner to be forced to engage in deflection angle shooting. While that is certainly true, what has been repeatedly overlooked, is that the defensive AA fire will also be deflection fire. Why is this such a huge deal, and why does it give an advantage that makes everyghing else more than worth while?

What makes deflection angle shooting harder that straight shooting, and why does this work entirely in the favor of the attacker?

Speed.

If your target is moving at 20kts, there is very little you need do to adjust your aiming point to hit your target, essentially, you aim where they are, and hit them. And when your target is several hundred feet long, this gives you a target that is hard to miss.

Now lets apply this to the attack profile I have posited. 200 miles per hour, so if you aim at the plane, you score a clean miss. You have to lead your target, and the faster the target, the more you have to lead it. Seems not to hard so far, right? But now they are 1,000 yards out, and 1,000 feet overhead, so you have just introduced some more variables to the equasion. The defensive AA gunner needs to account for the changing range as the aircraft closes in, which changes his lead point, but he also has to continually adjust for the affect of gravity on his rounds, as well.

So basically, your defensive AA gunner has to guess how much lead to give, how much balistics to adjust for, and both of these variables are constantly changing. For the heavier AAA, these factors are not as bad, but for the lighter AA, this forces the gunner to attempt to engage a small (compared to the merchantship), fast moving target, while adjusting his aimpoint in two dimensions.
 
This part is good information, for which I am glad and pleased to have, as without you post I likely would never have known it. It is also relevent to this thread, and therefore both on topic and appreciated. Thank you.

This other part I will only respond to once.
I come here, to the alternatehistory.com forums as a hobby, and strictly for entertainment purposes. I don't generally make it a habit to deliberately insult, nor provoke, my fellow forum community members.

So for this part, let me start off by saying, if I have offended, then I hereby and publicly appologise for any and all offense taken.


Allow me to explain. First, this was not intended as an insult, nor an assertion of any kind. It was in fact a two part joke. Back in the day, while serving in the US army of occupation of Berlin, I often had occasion to play a game with my comrades in arms called 'axis and allies'. On numerous occasions, a player would engage a sole enemy transport (that has but 1 chance in 6 of scoring a hit), with their bomber (which has a 1-4 chance of scoring a hit), and not only fail to hit the transport, but getting shot down by it. The simple math odds of that are something like 18:1, but it happened often enough in our games, that the standing joke went something like, "Grandma, with her coke-bottle spectacles, once again demonstrates here superior marksmenship by single handedly wiping out the entire enemy bomber squadron with antique deck gun".

The second part, was a Star Trek joke, based upon the scene where (IIRC Christopher Loyd, playing the Klingon commander), orders his gunner to aim for the federation ships engines, with the goal of capturing the ship. The gunner fires on the federation ship, but utterly destroys it, and exclaims (just before being shot by his commander) "Lucky shot, sir"!

Hence, while posting a thread about an alternate Germany, that takes a serious look at what they can realistically do to defeat the UK by building a purpose built "ship hunting" naval aviation force, and reading a response that seems to be implying that a lone British merchantman (even with 11 AA guns), is both going to shrug off the damage from a 5 plane attack, while at the same time infilcting serious losses upon such a force, well.:rolleyes:


A couple things about this part of your post. First, where in the thread do I endorce Nazism? So where, therefore, do I deserve to get slandered by the bolded portion? Second, if you are offended by threads that posit a Germany that is not as badly run as OTL Nazi germany was run, without some form of 'better' French and UK counter, perhaps avoiding those threads (and then being offended all over again), might be a better way to go? IIUC, OTL Nazi Germany beating France was a fluke, not some stroke of genius on the part of Germany, as OTL they didn't have any plans nor forces ready to take the war to the UK.:eek:

This is a fair point, I feel, but I have to respond with an american bit of slang. I really had no idea that folks reading this thread would get "Bent out of shape" over my previous post.

Once again, I apologise for any offense given.

Apology accepted and allow me to reciprocate as I did not mean to imply you were a "master racer" yourself and I should have chosen words more carefully.

Secondly I don't expect a counter punch from the Allies (Eastern or Western) to be better, just that there would be one and in many threads this does not happen, hence frustration and my apology for placing you in that basket
 

Saphroneth

Banned
Weapon weight can't be reduced by nearly 90% just by accepting a smaller maximum range.
What do you think controls maximum range? It's muzzle velocity! And that also affects accuracy.
Not to mention most of the weight is in the twin mounting and the ammo and breech and feed mechanism...
Reducing the barrel length by a bit is about all you could do to save weight, and if you do that you've essentially got an eight ton bomb lobber at which point you may as well just drop bombs.
 

hipper

Banned
Canons are not going to do it. If you gonna have a plane like that with internal bomb bay. Load torpedoes in there. Ditch the turret and all extra weight. Your best defence is range and size of the ocean. It will be a some time till escort carriers are a problem.

How good were German air launched torpedoes anyway?

If written realistically and not as wank this could be a fascinating tactical study. Once escort carrier become available in number though it will start getting a bit one sided.

Germany started the war without an air launched torpedo,

Later they copied the Italian air dropped torpedos but at first the only aeroplane to use them was a seaplane.
 

hipper

Banned
Yep. The figures you are providing I believe are for the OTL naval version of the weapons, which has some other factor from an airborn weapon.
If I have my numbers rigth, the naval version had a range exceeding 7,000 meters, while I need something just a we bit more than 1,000 meters. The naval version needed to propel it's rounds up, while mine will not.
to keep with the originally posited turret weight, lets consider. The M2 (like the ones I dealt with in the army) < 100 lbs, but lets call it 100 lbs. The turret say 1,000 lbs. We now have 800 lbs for a pair of 40mm aircraft mounted autocannons, so a max of 400 lbs each. What do you folks think? Can a 40mm autocannon be built, have say 1,200 yard range, with enough hitting power to penetrate a merchantmens hull from 1,000 yards out and 1,000 feet up be developed that fits this weight limit? Off the top of my head, I can say that I can definately get the range, but not sure about the penatrating power, I just plain don't know on this one.

Don't need the naval version, as I dont need the 7,000 + meter range nor ability to fire UP, as I will be firing from above, thus need much less of a cannon.

The penetration power could be a show stopper, if the lighter airborn cannon cannot pierce the hull from 1,000 yards.

I see. Well, lets take this one step at a time, shall we?
The lighter mounting of fixed weapons comes at a cost I don't want to have to pay.

I do want to give my gunner the most time I can to hit the target, true. This likely makes his fire more accurate, and thus is more effective. Although I should probably point out, my attack profile will never actually have me 'over the target', but rather 1,000 yards out.

First, my attack profile has me moving a say 200 miles an hour, on a paralelle course, and while this will always be a deflection shot, the change in range is going to be slower and much less than a conventional, charge right in attack. Secondly, I don't want multiple hits in the same area, but multiple hits well seperated from each other.

If your getting bounced by fighter, your already in trouble.:p
:D

Now for the rebuttal::cool:

By mounting the weapons in a light weight, but fixed mounting I doom myself to the following disadvantages.
1) I am forced to aim my plane at the target.
2) I am forcing the fellow flying the plane to double as my gunner. This both distracts him from bringing accurate fire to bear, and reduces the missions effectiveness overall.
3) I am forcing my planes to get much closer to the target than 1,000 yards. All other things being equal, shorter ranges mean more accuracy from the defenders AA.

Advantagious trade offs from heavier mountings.
1) With a turret mounted armament, my plane does not have to be aimed at the target ship, but can attack in a wide varity of attack profiles.
2) By allowing my gunner to concentrate on the task at hand, I will achieve better accuracy, and this is needed for the very specific targeting I am attempting, while the 'point at the target' attack profile really cannot deliver this sort of attack at all.:eek:
3) Maintaing my distance, will have a very drastic effect on the effectiveness of defensive AA fire, far more that most folks would suspect. It isn't simply a matter of being farther away, it is far more than that. An expert defensive AA gunner would have quite a bit harder time hitting a plane using my attack profile that the OTL one, and an inexperienced gunner is going to need a great deal of luck. Can anyone guess why?

Next point, the time on target, and broadside on aspect.
1) While giving the enemy a larger target seems like a bad idea, here are some things to consider here. My posited aircraft will be coming in around say 200 miles per hour (maybe more if we feel the need to waste the fuel), and this will limit the time My gunner has to bring his weapons to bear. Maintaining a constant bearing while on the approach, allows him to adjust in a single dimension, rather than two (range and altitude), which will also serve to increase his accuracy. This is not possible with the fixed mountings.

And finally, the big tomale'.
By keeping my distance from the target, I reduce the accuracy of their AA fire. It has been repetadly pointed out that my attack profile with cause my planes gunner to be forced to engage in deflection angle shooting. While that is certainly true, what has been repeatedly overlooked, is that the defensive AA fire will also be deflection fire. Why is this such a huge deal, and why does it give an advantage that makes everyghing else more than worth while?

What makes deflection angle shooting harder that straight shooting, and why does this work entirely in the favor of the attacker?

Speed.

If your target is moving at 20kts, there is very little you need do to adjust your aiming point to hit your target, essentially, you aim where they are, and hit them. And when your target is several hundred feet long, this gives you a target that is hard to miss.

Now lets apply this to the attack profile I have posited. 200 miles per hour, so if you aim at the plane, you score a clean miss. You have to lead your target, and the faster the target, the more you have to lead it. Seems not to hard so far, right? But now they are 1,000 yards out, and 1,000 feet overhead, so you have just introduced some more variables to the equasion. The defensive AA gunner needs to account for the changing range as the aircraft closes in, which changes his lead point, but he also has to continually adjust for the affect of gravity on his rounds, as well.

So basically, your defensive AA gunner has to guess how much lead to give, how much balistics to adjust for, and both of these variables are constantly changing. For the heavier AAA, these factors are not as bad, but for the lighter AA, this forces the gunner to attempt to engage a small (compared to the merchantship), fast moving target, while adjusting his aimpoint in two dimensions.

The Germans used a weapon in this class the BK37 it weighed 650 lbs in a non flexible mounting it deliverd a 37 mm shell in ap and HE format. I doubt it could be used in a turret mounting owing to recoil forces though a side mounting may be possible.

In actual attacks on ships aircraft found it expedient to get out of firing range as quickly as possible as aircraft are more fragile than ships.

You may want to consider basic human psychology people don't like being shot at, the pilot of an aeroplane will choose the attack profile that causes him least exposure. It's a Darwinian process.

Regards Hiper.
 
CalBear beat me to it.:eek: I second (third?:p) both.

I'd also add, 4x40mm in the nose of a bomber would be a good choice, plus useful for antitank. (Think Hurribomber...)
 
Germany started the war without an air launched torpedo,

Later they copied the Italian air dropped torpedos but at first the only aeroplane to use them was a seaplane.
They did have an air launched torpedo at the outbreak of war, but it was highly unreliable and the only aircraft capable of using it was the large slow He 59 float plane. It wasn't until May 1940 that improvements to the torpedo enabled the better He 115 float plane to carry it, though it was still unreliable.
It wasn't until the beginning of 1941 that the German's were able to get the torpedo to function reasonably well and fit it on a He 111.
 
These threads can seem quite confusing to old farts like me. It seems that U-boats are precluded from the premise although they were historically the most effective weapon the Germans had for sinking merchant shipping, and if they had a better torpedo early, sinking naval ships as well. The development of countermeasures reduced their effectiveness to the point of curtailing operations, until modifications permitted their return. It didn't really happen.

Just as the allies hadn't developed proper methods and weapons to defeat U-boats at the onset of war, with a flood of working systems unleashed in 1943, the Germans hadn't had any interest in studying methods of attacking ships from the air before 1941. The Stuka served as a dual purpose machine, as Rudel demonstrated, and as witnessed off Crete, but the Stuka had limitations in range, and couldn't operate well against air defenses. Condors became a noted scourge, using level bombing from low altitude, but was an aircraft not built for the purpose, and not modified properly to the task. It succumbed to AA defenses and air cover when such things were arranged, but that didn't happen right away. He-111 and Ju-88s also had their day, in their place. Their day came to an end with jeep carriers and the activities of a developed Coastal Command. These countermeasures would have also curtailed the success of radio-guided glide bombs.

The development of German aerial torpedoes is curious indeed. Just as the reason I don't believe in Sea Lion is that Germany began to develop the plan in May, 1940, they hadn't given a thought to the lack of an effective aerial torpedo until 1940 drew to a close. These things take time, and it was only due to Italian efforts that such things were eventually forthcoming come 1941. The thought that there were Germans giving serious considerations to aerial attacks on shipping seems dubious to me, due to the historical reliance on Italians and airliners to do the job. Also in mind must remain the fact that jeep carriers and Bofors guns in abundance weren't a big factor on the minds of the allies until the need arose.

Getting off topic, my mind stirs at the thought of Air Apaches with a bay full of 500 pounders, and 18 .50s blazing, coming in at wave-top level. For aerial anti-shipping, that's the image seared in my mind. They even had the best paint jobs.
 
Actually I think air dropped naval mines might actually be the most effective way for planes to sink merchantmen, during the last six months of the war they sank more tonnage than every other source IIRC
That's because the marine arm of the Luftwaffe had ceased to exist, and the U-boat fleet was doing little more than provide target practice to the Allied ASW forces.
 
This seems far closer to the mark of what I have in mind than anything else posted, the equivelant German weapon weighing in at around twice as much, and put together in typical Nazi-ish lack of forplanning, not to mention being designed for the anti-tank role rather than the anti-shipping role.

http://en.wikipedia.org/wiki/Vickers_S_gun

If the UK can develop this weapon, why not something in this weight class by the Germans for anti-shipping?

I don't understand?

If we are dealing with an alternate Germany that does go down the path of long range land based naval aviation, why are we supposing that they would not develop a more capable weapon? I posited a 400 lbs 40mm turret mounted weapon, and here we have a 320 lbs 40mm pod mounted weapon. The site linked even mentioned it was tested in a turret.

Can someone explaing to me why it is that an ATL Germany is assumed to be unable to develop a weapon along the lines I have posited?

Oh, and the British version used a 4 lbs projectal, and I have to wonder if the 320 lbs weight quoted includes the 48 lbs of the gun pods 12 round capacity.

Help me here.:)
 
Submarines in a walk. Nothing else comes even close.

Had the KM had a reasonable number of boats (the total force was only 57 boats, only 23 were capable of operation into the Atlantic shipping lanes) the Reich could have done vastly more damage. The Reich would not have been able to force a British Surrender, but the issue would have been very close. The U-boats sank 14 MILLION tons of shipping. Still, the KM failed, mainly because the Allies, primarily the U.S., constructed 38 million tons of merchant tonnage, built hundreds of specialized escorts. broke the Reich's codes, and invented a type of warfare that had never before been attempted.


Aircraft are a nice addition, especially if you can get them into restricted waters that the enemy has to transit, but they are far less capable in the open sea (too much sea, too few aircraft, limited operational window) and are much more vulnerable to the defensive armament that can reasonably be added to a merchant vessel without compromising its primary function. Among aircraft weapons the best option, by far, is the air dropped torpedo. Unlike warships, which have the speed and maneuverability to often avoid the deployed weapon, merchant ships (in WW II generally possessed with top speeds of 10-12 knots) are unable to dodge a torpedo. One torpedo was sufficient to sink or cripple almost any merchant vessel used by any nation throughout the war.

the "what if" effect of having auxiliary cruisers able to reach (approx.) 20 knots or so (comparable to their Dithmarschen-class http://german-navy.de/kriegsmarine/ships/auxships/dithmarschen/history.html supply ships?

operate in tandem with u-boats, they all carried torpedoes as well but also 5.9" guns.
 

CalBear

Moderator
Donor
Monthly Donor
the "what if" effect of having auxiliary cruisers able to reach (approx.) 20 knots or so (comparable to their Dithmarschen-class http://german-navy.de/kriegsmarine/ships/auxships/dithmarschen/history.html supply ships?

operate in tandem with u-boats, they all carried torpedoes as well but also 5.9" guns.

Surface raiders are useful, but they are, in general "one and done". They go out and raise hell until they are tracked down and sunk. They can tie up lots of naval assets, which is a positive, but subs can do the same, on their own, and can make multiple sorties. You can build two-three boats for the same materials as one auxiliary cruiser.

A raider gets too successful and the enemy will scare up enough resources, up to and including aircraft carriers, to make sure it get dead. Since the Reich was not seriously capable of challenging the RN, much less the USN and RN in a stand-up fight, having a carrier group out chasing a raider was less of an issue than it would have been had the British had to defend a series of islands across the entire Atlantic from enemy invasion

In the case of the Dithmarschen the KM chose, wisely IMO, to refrain from using it as a raider, choosing to keep it out of combat and utilize it as a force multiplier. That is why two of the class survived the war. Had they started trying to attack convoys there would have been zero surviving hulls.
 
Had the KM had a reasonable number of boats (the total force was only 57 boats, only 23 were capable of operation into the Atlantic shipping lanes) the Reich could have done vastly more damage. The Reich would not have been able to force a British Surrender, but the issue would have been very close.

What is a "reasonable number" exactly? France had nearly 80 submarines, many of them long ranged, with dramatically better basing options. However, it feels like somebody in the Admiralty was doing their job terribly wrong if France had a navy capable of bringing Britain to its knees.
 

CalBear

Moderator
Donor
Monthly Donor
This seems far closer to the mark of what I have in mind than anything else posted, the equivelant German weapon weighing in at around twice as much, and put together in typical Nazi-ish lack of forplanning, not to mention being designed for the anti-tank role rather than the anti-shipping role.

http://en.wikipedia.org/wiki/Vickers_S_gun

If the UK can develop this weapon, why not something in this weight class by the Germans for anti-shipping?

I don't understand?

If we are dealing with an alternate Germany that does go down the path of long range land based naval aviation, why are we supposing that they would not develop a more capable weapon? I posited a 400 lbs 40mm turret mounted weapon, and here we have a 320 lbs 40mm pod mounted weapon. The site linked even mentioned it was tested in a turret.

Can someone explaing to me why it is that an ATL Germany is assumed to be unable to develop a weapon along the lines I have posited?

Oh, and the British version used a 4 lbs projectal, and I have to wonder if the 320 lbs weight quoted includes the 48 lbs of the gun pods 12 round capacity.

Help me here.:)

How many 40mm shells are you imagining it will take to sink a single 10,000 ton, 400 foot long merchant vessel? Keep in mind that the ships can survive 100kg bomb direct hits, and many shrugged off 250kg bombs. You can manage to sink a barge (a small one) or a 65' fishing trawler with 40mm, but a SHIP? Not going to happen, not with only a single (or even a couple) aircraft attacking. The Vickers S AP shell wasn't even effective against Tiger tank top armor (25mm or ~1") but a similar gun will somehow sink a seagoing vessel, one that can survive North Atlantic storms?

At Bismarck Sea it took 110 bombers, supported by 50+ fighters, three days to sink eight transports (and 5 DD), most of them being coastals (the largest ship was 8,800 tons, four were under 5,000, one under 1,000). THREE DAYS, 150+ aircraft to kill 8 transports, all of them sunk by 500 pound bombs or by 21" torpedoes. If the Luftwaffe can put 150 aircraft over a convoy, every day for THREE DAYS, the British are in more than a little trouble, and its seems fairly likely that the Luftwaffe will be able to bring some bombs along.

Aircraft tend to be lethal when deployed in swarms, as singletons or two-three aircraft strafing elements they are an irritant.
 

Sycamore

Banned
This seems far closer to the mark of what I have in mind than anything else posted, the equivelant German weapon weighing in at around twice as much, and put together in typical Nazi-ish lack of forplanning, not to mention being designed for the anti-tank role rather than the anti-shipping role.

http://en.wikipedia.org/wiki/Vickers_S_gun

If the UK can develop this weapon, why not something in this weight class by the Germans for anti-shipping?

I don't understand?

If we are dealing with an alternate Germany that does go down the path of long range land based naval aviation, why are we supposing that they would not develop a more capable weapon? I posited a 400 lbs 40mm turret mounted weapon, and here we have a 320 lbs 40mm pod mounted weapon. The site linked even mentioned it was tested in a turret.

Can someone explaing to me why it is that an ATL Germany is assumed to be unable to develop a weapon along the lines I have posited?

Oh, and the British version used a 4 lbs projectal, and I have to wonder if the 320 lbs weight quoted includes the 48 lbs of the gun pods 12 round capacity.

Help me here.:)

So, what about my suggestion of the Germans developing an aircraft similar to the Lockheed AC-130 Spectre gunship for the anti-shipping role? One with a similar side-mounted large caliber gun (either the PaK-40 75mm cannon which they fitted on the JU-88P IOTL, the Bordkanone BK 75mm cannon which they fitted on the Hs 129 B-3 IOTL, or even the Pak 43 88mm cannon)? Here's a picture, to give you some idea of the layout I'm talking about...

800px-AC-130.JPEG


And there's another option as well, one which the Germans never really explored IOTL- aerial rocket artillery. Even IOTL, the Hs 129B had the load carrying capacity to be fitted out with a 150mm Nebelwerfer 41 multiple rocket launcher, if the Germans had been so inclined. Fitting an 210mm Nebelwerfer 42 MRL would have been even easier, since it only had half the weight of the Nw. 41 MRL, and the Hs 129B would have been capable of carrying two of them (enabling it to lay a barrage of 10 Wgr. 42 rockets down on a target)- but when the Luftwaffe adopted it IOTL, they attempted to adapt it into an air-to-air weapon (the Wfr. Gr. 21), a role for which it was patently unsuited. Why wouldn't a more sane leader of the German Luftwaffe simply adopt it as an air-to-ground weapon instead?

Think of something along the lines of the He 177 Grosszerstörer flying battleship variant- but tasked with the role of attacking enemy shipping vessels, the batteries of 33 obliquely mounted 21 cm (8¼ in) calibre rocket mortar tubes placed in its fuselage would be inclined to fire downwards instead of upwards. IMHO, it would've been far more suited to carry out this sort of anti-shipping role than the OTL experimental variant was suited to attack Allied bomber formations (and their numerous fighter plane escorts).
 

CalBear

Moderator
Donor
Monthly Donor
What is a "reasonable number" exactly? France had nearly 80 submarines, many of them long ranged, with dramatically better basing options. However, it feels like somebody in the Admiralty was doing their job terribly wrong if France had a navy capable of bringing Britain to its knees.

France also had three oceans to cover and was a firm ally (rather like the fact that the Admiralty doesn't have many sleepless nights these days because the USN has 10 CVN and close to 100 SSN/SSGN/SSBN, unless the concern is that the U.S. could use a few more hulls :)). That being said, if a hostile Paris could have surged 80 boats into the sea lanes the disruption would have been huge. The Admiralty, BTW, DID have major issues with its war planning (the UK didn't trade 99 year rent free base leases for 50 OLD destroyers because the Admiralty had managed an exceptional building program and it wasn't using converted fishing boats as solo escorts by choice).

Problem is that you can't surge 80 boats, not if you want a constant threat. You can, at best, have one boat in three on station, assuming none need repair/overhaul the others are either in transit or along side being refueled/rearmed/resupplied. A WW II U-boat could manage about 6 knots while submerged/17 surfaced so the average travel day is 200-300 miles, depending on air/surface threat. That's 5 days transit each way.

The KM could only have 8-10 boats on station at any one time. None had radar (and even if they did its range was very limited due to antenna height) so the best that could be done was to put the boat in the shipping lanes and hope for the best. Despite that, they caused more damage to the British war effort than the entire Luftwaffe and all of the KM's surface ships combined. Imagine if the Reich had started the war with 200 Type VII instead of 25, and had been able to have 50+ boats on station 24/7.
 
France also had three oceans to cover and was a firm ally (rather like the fact that the Admiralty doesn't have many sleepless nights these days because the USN has 10 CVN and close to 100 SSN/SSGN/SSBN, unless the concern is that the U.S. could use a few more hulls :)). That being said, if a hostile Paris could have surged 80 boats into the sea lanes the disruption would have been huge. The Admiralty, BTW, DID have major issues with its war planning (the UK didn't trade 99 year rent free base leases for 50 OLD destroyers because the Admiralty had managed an exceptional building program and it wasn't using converted fishing boats as solo escorts by choice).

Problem is that you can't surge 80 boats, not if you want a constant threat. You can, at best, have one boat in three on station, assuming none need repair/overhaul the others are either in transit or along side being refueled/rearmed/resupplied. A WW II U-boat could manage about 6 knots while submerged/17 surfaced so the average travel day is 200-300 miles, depending on air/surface threat. That's 5 days transit each way.

The KM could only have 8-10 boats on station at any one time. None had radar (and even if they did its range was very limited due to antenna height) so the best that could be done was to put the boat in the shipping lanes and hope for the best. Despite that, they caused more damage to the British war effort than the entire Luftwaffe and all of the KM's surface ships combined. Imagine if the Reich had started the war with 200 Type VII instead of 25, and had been able to have 50+ boats on station 24/7.
Word. And the Germans never had a third of their force on station; they kept more boats in training, so it was more like a fifth...:rolleyes:

As for the proposed earlier Type XXI, that's really a non-starter. The Germans only saw the need after the Brits put so many LR mari pat a/c over the Atlantic & Biscay...:eek: Everybody, but everybody, figured subs would operate mostly surfaced, which is why all pre-WW2 boats look the way they do.

Could the Germans have adopted snort sooner? Certainly, & that alone would have been a big deal--but not the game-changer the Type XXI was. More Type IXs would have been major headaches for the Brits, by opening up more-distant patrol areas. Basing in Dakar would have been huge.:eek:

In short, it's harder to fix the problem technologically than geographically--or politically.
 
the "what if" effect of having auxiliary cruisers able to reach (approx.) 20 knots or so (comparable to their Dithmarschen-class http://german-navy.de/kriegsmarine/ships/auxships/dithmarschen/history.html supply ships?

operate in tandem with u-boats, they all carried torpedoes as well but also 5.9" guns.

Surface raiders are useful, but they are, in general "one and done". They go out and raise hell until they are tracked down and sunk. They can tie up lots of naval assets, which is a positive, but subs can do the same, on their own, and can make multiple sorties. You can build two-three boats for the same materials as one auxiliary cruiser.

A raider gets too successful and the enemy will scare up enough resources, up to and including aircraft carriers, to make sure it get dead. Since the Reich was not seriously capable of challenging the RN, much less the USN and RN in a stand-up fight, having a carrier group out chasing a raider was less of an issue than it would have been had the British had to defend a series of islands across the entire Atlantic from enemy invasion

In the case of the Dithmarschen the KM chose, wisely IMO, to refrain from using it as a raider, choosing to keep it out of combat and utilize it as a force multiplier. That is why two of the class survived the war. Had they started trying to attack convoys there would have been zero surviving hulls.

guess my scenario is to subsidize the marginal cost of additional/larger engines for some percentage of commercial ships being built where they would be able to keep pace with the Dithmarschen-class

to facilitate u-boat operations farther afield and for longer duration.

(and pocket battleship operations until they were eliminated)

my thinking was not to build auxiliary cruisers at the expense of u-boats but build a "ghost fleet" (one can submerge, the other assume a disguise)
 
Top