Alternate history speculation

[Lert]

Alternative history. Late 1941, early 1942.

 

Graf Spee survived the battle of the River Plate with minor damage, managed to steam back to German occupied ports to get repaired, and was sent back to sea for additional commerce raiding, this time to prevent convoys from reaching Britain.

The weather was kind to Bismarck, allowing the latter to escape without getting spotted by seaplanes, preventing her to eat that fateful torpedo to the rudder. She is loose in the atlantic.

Graf Zeppelin was completed as planned and commissioned in early 1941, managing to escape into the atlantic.

Tirpitz finally also managed to escape under the cover of night to make it into the atlantic.

 

These four ships, famous for their fates, loose in the atlantic for their intended purpose of raiding commerce, sinking merchantmen and preventing supplies from reaching Great Britain. Would they have had an appreciable effect on the war? Would the US have sent a significant task force to try and deal with these four ships, would that have affected the war in the pacific? Would Britain have been able to hold out?

[Captain_Dorja]

Not that it really matters, but my opinion is as follows.

All it would have done was brought the US into overt war sooner, and considering that we DID send substantial fleets after those ships even when all they were doing was sitting idle in Norway, we'd have done it for certain if they were at liberty in the Atlantic. That said, I doubt the conventional raiding would have been that successful anyway. For one, at the time Graf Spee was sunk, it was already getting harder for her to successfully raid where she was, and that was essentially a peripheral theater. To be fair, much later, when opposition was a lot stronger, Admiral Scheer managed an even more successful raider cruise, being the most successful conventional warship surface raider of the High Seas Fleet, but overall it's immaterial. The German surface raiders contributed so little that the most they can really be considered is a propaganda coup for the Germans, but even that wasn't very valuable because their inevitable defeat meant at least an equally larger propaganda coup for the Allies, plus removal of a threat that actually existed but couldn't ever really harm them.

[1Sherman]

The Royal Navy and the RCN hunker down at their major Atlantic ports (e.g. Halifax) and focus their ship-building efforts on subs and CVs to kill the German ships. Ultimately, they are successful, but the diverted resources means that fewer ships are able to escort the convoys across open water, leading to greater losses from the wolfpacks. To end this, the British use the Lend-Lease Act to get a few CVs from the Americans, who end up giving them several Casablancas and Independences as well as (dare I say) an Essex or two. As well, greater pressure is placed on Bletchley Park to develop ASDIC to counter the U-Boats and to break the Enigma cipher. In short, the Battle of the Atlantic becomes more like the Battle of the Pacific. Land-based aircraft and surface ships fall out of favour and are replaced by subs scouting the oceans from below and fast, powerful CV-based planes who numbers are legion and who strike with hellish fury upon any target they find.

[ZombieFlanders]

Bigger focus on tech, especially radar and sonar. More convoys would have been interfered with, and thus more liberty/cargo ships sunk means less to aid in the effort. If there was fair warning of the presence of these ships and wolf-packs from radar and sonar then convoys could be diverted and at least some losses averted.

 

To counter the threat more resources certainly would have been transferred to the Atlantic. More ships, but also more land based aircraft in numbers as well as capability. More bombers, less recon, Iceland is an unsinkable aircraft carrier/depot. 

 

The west coast of the US would still need to be protected and would have been more vulnerable, and island hopping would have been pushed back most likely. Guadalcanal may not have been in 42, at least not until the Atlantinc was dealt with. 

 

Over time not allies till win since the production capacity in NA would out-pace that in Germany and occupied Europe. 

[LordBenjamin]

I'm of the opinion that we knew or would shortly know quite a bit more about the Bismarck from Enigma than we let on at the time.    Allies had more ships, more planes, and could read their mail.   No matter how long it took the ending was going to be the same.

[Phoenix_jz]

Remember how much was set loose to hunt the Graf Spee? Force de Raid and Force H?

 

You can bet every fast modern BB and British battlecruiser available would be on the hunt, plus carriers. 

 

Such an event would have major repercussions elsewhere, however. The fact the British suddenly have this situation to distract then will do wonders for the Italian war effort, freeing up their ability to act aggressively greatly.

 

Ultimately, though, the ships would have little to no hope of escaping back to German waters... So, while they might run riot for a while, I doubt they would be able to last for long enough to say, win the war for Germany. If they're out past the Japanese entry into the war... Well, now the Americans will be shooting to kill as well.

[FayFay731]

What if the Pinguin and Komoran survived their battles with British cruisers?

Then they'll rule the Atlantic.

[Dunk_Master_Flex]

I think one saying fits this situation quite well, "You can run but you'll just die tired."

 

The amount of resources allocated for the destruction of Kriegsmarine capital ships should make this very obvious but Britain and the Allies will put every possible ship out on the hunt for all these ships. The Atlantic is a big place however, it's not infinity. The ships will get found and hunted down one by one, they will use their generally faster speeds to escape however, it will be almost impossible to resupply, repair damage and get back to friendly ports.

 

More Allied shipping and warships are lost however, I don't see this turning the war at all.

[mofton]

This situation isn't actually too dissimilar from Operation Berlin in Jan-March 1941.

In that raid Scharnhorst and Gneisenau got loose into the Atlantic as a pack together, in total sinking 22 ships. They stayed out for 60 days to achieve that. Simultaneously the Scheer was loose in the Atlantic (and Indian Oceans) breaking through the Denmark Strait in late March to return to Norway. The Admiral Hipper was also active in the Atlantic in February '41. A busy time.

So a scenario of several heavy German warships being loose in the Atlantic is not without precedent. Scharnhorst, Gneisenau, Hipper and Scheer in early 1941 vs. Bismarck, Tirpitz, Graf Zeppelin and AGS in late 1941/early 1942 is in some ways comparable.

Considerations -

• The KM showed a habit for operating the heavy ships together where possible, Scharn & Gneis on Op Berlin, Prinz Eugen with Bismarck, Hipper and Scheer together at Barents Sea. Doing so concentrates fighting power and makes intercepting with a powerful enough force difficult. However it also means you can only be in one place attacking one convoy
• Scharn and Gneis declined combat with even old unmodernized Battleships such as Ramillies and Malaya. I'm not sure if Bismarck&Tirpitz together would or wouldn't
• The Bismarck and Berlin operations were supported by a gaggle of German tankers which provided fuel and scouting. Friedrich Breme was sunk in May '41 Gonzenheim in June, Altmark went to Japan, others were variably lost or redeployed in 1941 and might not be available in this timeline
• GZ is a real wildcard in terms of effectiveness, aside from the IJN's Indian Ocean Raid with very different ships we don't have much of a benchmark

The best British response would have been to form responsive task forces of whatever aircraft carriers and modern battleships were available while continuing the policy of escorting large convoys with battleship-level firepower wherever possible. Bigger convoys can still be escorted by a single ship at greater risk but I think it's a trade off to take. Depending on when in '41-'42 the RN may be pretty low on ships, Ark Royal was sunk in the Med in November 1941. HMS Illustrious was out of the war until Feb '42, as was Formidable after battle and collision damage. Victorious was available. Indomitable was commissioned in October 1941, Indomitable went to the far east in early '42 but might have been redeployed if the Atlantic situation was different. The cupboard's pretty bare.

The biggest German impact would be a sudden shock to the supply lines at a critical time, overall even multiplying the success of Scheer and Op Berlin surface ships are unlikely to sink enough ships in the long term, but totally disrupting the convoy system for a short-medium period would be disproportionately damaging.

When -

With the US entry to the war in Dec '41 additional units come in, including Ranger, North Carolina and Washington, all very useful assets.

[Eisennagel]

3 hours ago, 1Sherman said:

The Royal Navy and the RCN hunker down at their major Atlantic ports (e.g. Halifax) and focus their ship-building efforts on subs and CVs to kill the German ships. Ultimately, they are successful, but the diverted resources means that fewer ships are able to escort the convoys across open water, leading to greater losses from the wolfpacks. To end this, the British use the Lend-Lease Act to get a few CVs from the Americans, who end up giving them several Casablancas and Independences as well as (dare I say) an Essex or two. As well, greater pressure is placed on Bletchley Park to develop ASDIC to counter the U-Boats and to break the Enigma cipher. In short, the Battle of the Atlantic becomes more like the Battle of the Pacific. Land-based aircraft and surface ships fall out of favour and are replaced by subs scouting the oceans from below and fast, powerful CV-based planes who numbers are legion and who strike with hellish fury upon any target they find.

 

 

Doesn't matter at all.  The bigger ships can chase German raiders all day all year long.  Much of the brunt in the Submarine war were carried by small corvettes and escort ships that could easily be mass produced in huge numbers.  These ships also bore the brunt of escort duties.

 

Subs going after raiders are vastly inefficient.  They are too slow to chase after them and need to be positioned well ahead to expect where the raider is going to be.   Subs underwater only move around 8 knots, and at the surface around 20 knots.   A German surface raider is much faster than that.  Furthermore the ability of a sub to detect a ship isn't great unless the sub is prepositioned on a route with dense sea traffic, using luck on a target rich environment.  They can only listen to the sound.  Visual sighting, and even if the sub has surfaced to use radar, range is very limited because of the short height of the sail.  There is a reason why spotters, rangefinders and radars are placed on top of the tall masts on ships.  The technology to make subs go after ships much more effectively isn't going to happen for another ten years.

 

CV planes are poor in range, since they are mostly single engined aircraft with limited fuel capacity.  Far more important are land based four engined aircraft because they can carry a lot of fuel for great flight endurance and range, and they can carry radars, torpedoes and depth charges.  Land based four engined aircraft on the Allied side and the insufficient number of it, mainly operating the FW-200 Condor aka Scourge of the Atlantic, on the Axis side, sealed the fate for the one who failed to use them in the proper numbers.   The FW-200 did much damage despite being only a converted passenger liner, imagine if the Germans had proper bomber based four engined aircraft.

 

You really need radar to find submarines on the water, as even when surfaced, a submarine is extremely difficult to eyeball on the surface.  You also need aircraft that can listen in submarine transmissions, which means additional equipment on the plane, and extra crew to man those equipment and more crew means more eyeballs looking at the ocean.  You need aircraft with glass noses and glass blisters on the side and on the bottom for observers to look down upon the surface.  Surface viewing isn't optimal on singled engined aircraft for the lack of glass noses. Hence, four engined land based planes once again, either dedicated in design, or converted from strategic land based long ranged bombers.

 

The Germans were the first to develop anti radar coatings on submarines (or for use anywhere) in the world because of this.  Today, modern submarines have radar absorbent coatings in addition to a more radar stealthy upper hull shape, making them radar stealthy above water and sonar stealthy underwater.

 

A sub chaser works by using radar to detect surfaced submarines and "chase" after them, fighting them with guns and depth charges.  You don't go around pinging the ocean looking for subs in open water because the sonar will work against you, as the sub will pick up the sonar first, and they will be aware of your presence and location.

 

As for surface raiding, the whole concept was dead as soon as the long ranged radar equipped surveillance aircraft were deployed.  

 

 

 

[1Sherman]

17 minutes ago, Eisennagel said:

 

 

Doesn't matter at all.  The bigger ships can chase German raiders all day all year long.  Much of the brunt in the Submarine war were carried by small corvettes and escort ships that could easily be mass produced in huge numbers.  These ships also bore the brunt of escort duties.

 

Subs going after raiders are vastly inefficient.  They are too slow to chase after them and need to be positioned well ahead to expect where the raider is going to be.   Subs underwater only move around 8 knots, and at the surface around 20 knots.   A German surface raider is much faster than that.  Furthermore the ability of a sub to detect a ship isn't great unless the sub is prepositioned on a route with dense sea traffic, using luck on a target rich environment.  They can only listen to the sound.  Visual sighting, and even if the sub has surfaced to use radar, range is very limited because of the short height of the sail.  There is a reason why spotters, rangefinders and radars are placed on top of the tall masts on ships.  The technology to make subs go after ships much more effectively isn't going to happen for another ten years.

 

CV planes are poor in range, since they are mostly single engined aircraft with limited fuel capacity.  Far more important are land based four engined aircraft because they can carry a lot of fuel for great flight endurance and range, and they can carry radars, torpedoes and depth charges.  Land based four engined aircraft on the Allied side and the insufficient number of it, mainly operating the FW-200 Condor aka Scourge of the Atlantic, on the Axis side, sealed the fate for the one who failed to use them in the proper numbers.   The FW-200 did much damage despite being only a converted passenger liner, imagine if the Germans had proper bomber based four engined aircraft.

 

You really need radar to find submarines on the water, as even when surfaced, a submarine is extremely difficult to eyeball on the surface.  You also need aircraft that can listen in submarine transmissions, which means additional equipment on the plane, and extra crew to man those equipment and more crew means more eyeballs looking at the ocean.  You need aircraft with glass noses and glass blisters on the side and on the bottom for observers to look down upon the surface.  Surface viewing isn't optimal on singled engined aircraft for the lack of glass noses. Hence, four engined land based planes once again, either dedicated in design, or converted from strategic land based long ranged bombers.

 

The Germans were the first to develop anti radar coatings on submarines (or for use anywhere) in the world because of this.  Today, modern submarines have radar absorbent coatings in addition to a more radar stealthy upper hull shape, making them radar stealthy above water and sonar stealthy underwater.

 

A sub chaser works by using radar to detect surfaced submarines and "chase" after them, fighting them with guns and depth charges.  You don't go around pinging the ocean looking for subs in open water because the sonar will work against you, as the sub will pick up the sonar first, and they will be aware of your presence and location.

 

As for surface raiding, the whole concept was dead as soon as the long ranged radar equipped surveillance aircraft were deployed.  

 

 

 

 

Lert asked for ideas, I gave him mine. I figured that in the scenario given, the RN would be scared to send its BBs out against 2 BBs, a CA/BB hybrid, and a CV and would use methods that were harder to counter, e.g. subs. As well, while CV-based planes may have a short range, CVs themselves do not. It's the entire purpose of a CV to act as a mobile base for aircraft. Keep enough of them around and enemy planes will drop like flies (e.g. Marianas Turkey Shoot). As well, that so-called "stealth" stuff you say German U-Boats had didn't exactly do them much good against Allied ships and planes considering that three quarters of everyone who sailed on a U-Boat was killed.

[Eisennagel]

 

 

That was first generation stealth and its application was too little and too late.  But the Germans did create the principles of RAM (radar absorbing materials) that were used after the war.  

 

CVs are not the most ideal for subhunting because ask yourself, do these single engined aircraft ever carried acoustic homing torpedoes?  Wrong era.  Can they carry depth charges?  No, only larger aircraft with bomb bays can.  Single manned aircraft, the pilot is already busy flying the plane, his wings obscures downward vision, can't use a binoculars to scan the water.  Subs have a pretty small visual radius.  Even with a two seater, downward view is obscured by the wings.  Assuming even if you spot a submarine, the submarine can also spot the aircraft and dive underwater before strike aircraft can reach the area.  And those strike aircraft can only be fitted against surface targets.  Spotters are basically hardly equipped with anything so they can fly with the most range and loiter time.  If the spotter carries a small bomb, it better get that bomb hit with only one chance.  If the submarine managed to dive, the bomb would be useless.   The plane would have to call in escort ships to scour the area.  

 

If a four engined bomber plane on the other hand, has much better chances of finding a submarine with downward and sidewards looking radar, with observers manning the glass nose and the glass blisters along the side and bottom of the aircraft.  And then it can engage the submarine by dropping bombs or dropping depth charges from the air.  It can do it directly, without calling for a separate strike or escort ships to the area.

 

For the CVs to help hunt submarines, the best method would be two engined aircraft, though that would limit the number of planes carried onboard if you are a small carrier, and this dictated the great increase in size of carriers after the war.  Helicopters would also revolutionize ASW for CVs and surface ships but that won't happen after a decade.  What CVs can do is use their fighter cover to defend the convoy against enemy long range patrol aircraft and bombers --- these long range aircraft are also diverting enemy subs towards the convoy.

 

Still the more decisive vehicles for ASW during the war was the sub hunters --- destroyer escorts, frigates, sub hunters, escort vessels, corvettes --- often with cheap to make triple expansion engines, that can be produced in huge numbers, along with land based long range maritime patrol and ASW aircraft.  The smaller ships are harder, though not impossible to kill with submarines, as they are also harder to spot and it is because of that, the subs are often caught by surprise.  Especially by wooden sub hunters --- these wooden ships will not bounce radar and are difficult to detect with surface radar.  And so they have an advantage in the spotting contest against a sub.

 

As for the scenario given, the RN would not be afraid to send the BBs out to hunt the German raiders, but the problem is that these BBs could not catch them unless they are fast battleships or battlecruisers.  QE class, Revenge class, won't catch them.  The slow battleships are better off somewhere protecting convoys and having the enemy brought to them.  Against raiders and marauding ships, you will need cruisers, lots of cruisers, hence the RN was also trying to make them as cheap as possible to build as many as they can (foregoing heavy cruisers, downgrading 12 gun light cruisers to 9 gun types for lower cost and quicker production.)  Even when outgunned, the cruisers can still damage and stall the raider or marauder until bigger ships arrived or an air strike is called.

 

 

[mofton]

26 minutes ago, Eisennagel said:

CVs are not the most ideal for subhunting because ask yourself, do these single engined aircraft ever carried acoustic homing torpedoes?  Wrong era.  Can they carry depth charges?  No, only larger aircraft with bomb bays can.  Single manned aircraft, the pilot is already busy flying the plane, his wings obscures downward vision, can't use a binoculars to scan the water.  Subs have a pretty small visual radius.  Even with a two seater, downward view is obscured by the wings.  Assuming even if you spot a submarine, the submarine can also spot the aircraft and dive underwater before strike aircraft can reach the area.  And those strike aircraft can only be fitted against surface targets.  Spotters are basically hardly equipped with anything so they can fly with the most range and loiter time.  If the spotter carries a small bomb, it better get that bomb hit with only one chance.  If the submarine managed to dive, the bomb would be useless.   The plane would have to call in escort ships to scour the area.  

 

 

I think you're doing carrier-borne ASW aircraft a disservice and yes, they did launch acoustic homing torpedoes such as FIDO towards the end of the war. As far as I'm aware they could carry depth charges or depth bombs, and either way they had decent successes. For instance -

USS Card with 8 U-boat kills to FIDO and depth charge attacks by her Wildcat/Avenger Airgroup - http://uboat.net/allies/warships/ship/2487.html

USS Bogue with 7 kills and 2 contributions by her air group - http://uboat.net/allies/warships/ship/2486.html

USS Core with 4 kills - http://uboat.net/allies/warships/ship/2489.html

It's not just in kills, and contributions. An Escort Carrier has an air group immediately available to assist a convoy or scour an area. Long range aircraft may spend a good chunk of their mission in transit to and from the key area. Even if light aircraft are unable to attack their presence may cause U-boats to dive and effectively immobilize themselves. Plus if spotted, you have a cue to send a couple of escorts out towards, which was frequently effective. In addition and although not direct action, Escort Carrier air groups may shoot down those pesky Condor's who are vectoring the U-boats onto you. HMS Audacity alone accounted for 7 Condors which is a good chunk of those available, potentially sparing her convoy from U-boat attack.

Avenger type aircraft could spot and still carry an ASW payload, and HMS Warspite's spotter Swordfish indicated she could do by accounting for U-64 at the second battle of Narvik.

 

In total I'd guess that long range aircraft may have gotten more kills, especially in the Bay of Biscay but I'd take it that single engined aircraft were entirely capable, and potentially had some advantages as well as a bigger impact and potentially more kills per aircraft.

[_Sarcasticat_]

6 hours ago, Lert said:

Alternative history. Late 1941, early 1942.

 

Graf Spee survived the battle of the River Plate with minor damage, managed to steam back to German occupied ports to get repaired, and was sent back to sea for additional commerce raiding, this time to prevent convoys from reaching Britain.

The weather was kind to Bismarck, allowing the latter to escape without getting spotted by seaplanes, preventing her to eat that fateful torpedo to the rudder. She is loose in the atlantic.

Graf Zeppelin was completed as planned and commissioned in early 1941, managing to escape into the atlantic.

Tirpitz finally also managed to escape under the cover of night to make it into the atlantic.

 

These four ships, famous for their fates, loose in the atlantic for their intended purpose of raiding commerce, sinking merchantmen and preventing supplies from reaching Great Britain. Would they have had an appreciable effect on the war? Would the US have sent a significant task force to try and deal with these four ships, would that have affected the war in the pacific? Would Britain have been able to hold out?

It's likely that those four ships in the Atlantic would absolutely smash. There's not much Britain can do against a task force involving Bismarck or Tirpitz as well as Graf Zepplin. It's more likely that the Graf Spee will continue to wreak havoc elsewhere. Personally, without Tirpitz and Bismarck kicking the bucket, and Graf Zepplin being finally completed, history would have been a lot less kind to Britain, but I'm sure she would've held out. You can sink ships, but you can't sink a country. Anyway, I bet production of the large bombs used to destroy Tirpitz would have been sped up, and if anything, suicide kamikaze plans would have been used against the Bismarck and Tirpitz before Graf Zepplin's planes swooped in. 

 

Alternate history: late 1945/1946 - present.

Kriegsmarine fleet torpedo boat T-35, a war reparation to the U.S., was not scrapped and was stationed as a dry-dock museum ship along the east coast and still continues to be in nearly impecable condition despite the years and is available for tours in any part of the ship.

 

My greatest wish right now. 

[Eisennagel]

1 hour ago, mofton said:

I think you're doing carrier-borne ASW aircraft a disservice and yes, they did launch acoustic homing torpedoes such as FIDO towards the end of the war. As far as I'm aware they could carry depth charges or depth bombs, and either way they had decent successes. For instance -

USS Card with 8 U-boat kills to FIDO and depth charge attacks by her Wildcat/Avenger Airgroup - http://uboat.net/allies/warships/ship/2487.html

USS Bogue with 7 kills and 2 contributions by her air group - http://uboat.net/allies/warships/ship/2486.html

USS Core with 4 kills - http://uboat.net/allies/warships/ship/2489.html

It's not just in kills, and contributions. An Escort Carrier has an air group immediately available to assist a convoy or scour an area. Long range aircraft may spend a good chunk of their mission in transit to and from the key area. Even if light aircraft are unable to attack their presence may cause U-boats to dive and effectively immobilize themselves. Plus if spotted, you have a cue to send a couple of escorts out towards, which was frequently effective. In addition and although not direct action, Escort Carrier air groups may shoot down those pesky Condor's who are vectoring the U-boats onto you. HMS Audacity alone accounted for 7 Condors which is a good chunk of those available, potentially sparing her convoy from U-boat attack.

Avenger type aircraft could spot and still carry an ASW payload, and HMS Warspite's spotter Swordfish indicated she could do by accounting for U-64 at the second battle of Narvik.

 

In total I'd guess that long range aircraft may have gotten more kills, especially in the Bay of Biscay but I'd take it that single engined aircraft were entirely capable, and potentially had some advantages as well as a bigger impact and potentially more kills per aircraft.

 

 

They are contributive but not decisive.  ASW load for single engined CV aircraft is quite limited.  The air drag from those charges would limit the range of the aircraft.  

 

Furthermore you have problems spotting submarines at night for obvious reasons without radar.  You really need maritime aircraft at that.  Subs would recharge their batteries often at night.  

 

Once again I did mention that spotters can cue escorts and fighter cover can take down opposing maritime aircraft.  

 

But the decisive turnaround lay with the small escort ships and the long range maritime aircraft, both that are laden with radar that can search both day and night.  Escort carriers are contributive.  Even the wrong aircraft for the job at the right time and the right place can still be contributive.  But they cannot turn things around by themselves.

 

 

[mofton]

7 minutes ago, Eisennagel said:

They are contributive but not decisive.  ASW load for single engined CV aircraft is quite limited.  The air drag from those charges would limit the range of the aircraft.  

Furthermore you have problems spotting submarines at night for obvious reasons without radar.  You really need maritime aircraft at that.  Subs would recharge their batteries often at night.  

Once again I did mention that spotters can cue escorts and fighter cover can take down opposing maritime aircraft.  

But the decisive turnaround lay with the small escort ships and the long range maritime aircraft, both that are laden with radar that can search both day and night.  Escort carriers are contributive.  Even the wrong aircraft for the job at the right time and the right place can still be contributive.  But they cannot turn things around by themselves.

The ASW load is limited but entirely adequate to either sink, damage or force to dive a submarine, or spot and cue onto it. The instances of something like a VLR Liberator or Sunderland launching repeated attacks are few and far between. The Avenger was widely used and had a >1,000 mile range with stores carried internally, the Swordfish is still staying up for 5 hours with payload, and it's flying time to defend a convoy is practically nil instead of hours and hours from Iceland.

At least the Swordfish could mount centimetric radar - ASV, I know Avengers could too. Both suitable for detecting submarines at night.

It's just not the wrong aircraft for the job, it's entirely effective, it's a different approach to a long range Liberator etc. ex-Iceland or Northern Ireland but it's very impressive. As the statistics show that convoys with any air attack were vastly less likely to suffer casualties it's well worthwhile, especially as the RAF for instance was obsessed with 1,000-bomber raids to 'dehouse' the German workforce and deeply resented skimming off even a handful of bombers for long-range ASW conversion.

 

How do you define 'decisive'? A relatively small number of single engine ASW aircraft achieved about 84 kills of U-boats, that's more than for instance all the Flower class Corvettes sank (50 U-boats).

Sorry, you did mention AA work.

[Eisennagel]

 

 

If the Germans were at it again, the most decisive thing to do again was to secure Norway.  Securing Norway --- which wasn't done in WW1 --- would allow iron and ore shipments from Scandinavian countries to flow to Germany.  During WW1, the Germans also had substantial interference from the Russian fleet in the Baltic until the Revolution happened.  Its quite possible that during WW2, if those 10 German destroyers won't have beached and lost, their sailors won't be beached in Norway and added several hundreds of men to assist the German forces taking Norway and turned the tide of the battle for the Germans.

 

So the Brits had to once again, stop the invasion of Norway, this time with their main battle fleet.  This is likely going to end up with some big battle in the North Sea once again.  

 

After that, due to the strategic importance of the region, Norway is likely to tie up some German naval forces for its defense.

 

If Germany had not invaded Russia, a significant amount of the Luftwaffe would remain in the Western front to contest aerial control of the North Sea and English Channel.  That means the Germans may continually bomb English ports, causing damage to the ports and sinking ships, but may also incur casualties among the planes in a tit for tat battle.  There would be a time when the introduction of BF-109F and the FW-190A may give the Luftwaffe a window of opportunity in aerial superiority over the RAF.

 

After the Fall of France, the German Army would turn to the south...in North Africa.  Instead of an expeditionary army, you have the full force of the Wehrmacht, with Rommel getting more tanks and plane support.    This time, the Luftwaffe would switch its main forces from the northern coast of France and deploy more units all over Italy.   German forces gets stationed on Spain thanks with Franco's help, and German paratroopers made a monumental assault on Gibraltar and then Malta.  With heavy Luftwaffe assistance, the Royal Navy and the Regina Marina enters into a series of bloody slugging matches as both attempt to intercept and protect their convoys.  

 

With the African campaign --- with the objective of getting the oil fields in the Middle East --- the German Navy raiding and anti commerce campaign against Great Britain is suspended.  Leadership orders German naval units to the Mediterranean to assist in the effort.  That means all four battleships --- Bismarck, Tirpitz, Scharnhorst, Gneisnau, the surviving cruisers and Panzerschiffes, submarines, torpedo boats and destroyers.  German units would have to go across the North Sea into the North Atlantic, headed to Gibraltar, now under German control.  Other units would attempt to break through the English Channel, with heavy cover from Luftwaffe fighter wings under the command of Adolf Galland and Werner Moelders.  With Franco's assistance, Luftwaffe also stations bomber and fighter wings in the Spanish coast.  The Germans helping to put Franco in power is now paying off.

 

The Royal Navy responded, with a main battlefleet of the Hood, Prince of Wales, Nelson, Rodney and the King George V, and the remaining older battleships, to intercept the German fleet from getting into the Mediterranean.  Failure to stop the German fleet would mean that North Africa would fall, and Rommel would be planting the German flag from Egypt all the way to Iraq.