H-Class battleships (and the whole Plan Z that stipulated the construction of six of these beasts) were a perfect example of what a colossal waste of resources happens when weapons systems are designed to achieve a totally wrong objective. Especially when this objective is totally unrealistic.

H-class battleships (super-battleships, actually) were real monsters. The first variation (H-39) was essentially an enlarged Bismark-class battleships (56,444 vs 41,700 tons standard displacement and 406mm vs 381-mm main guns).

The next variations (H-41 to H-44) were bigger and bigger and bigger with standard displacement of 68,800, 90,000, 111,000 and a whopping 131,000 tons respectively. H-41 was supposed to be armed with 420mm main guns, H-42 and H-43 – with 480mm (bigger than the guns of Japanese Yamato-class super-battleships) and H-44 – with unbelievable 508mm (20-inch) guns, having almost the same caliber as the submarine- and destroyer-launched torpedoes.

Fortunately for the Kriegsmarine, its commander-in-chief Erich Raeder made the decision to stick to the initial H-39 design. Even more fortunately, right after the outbreak of World War II, he had the common sense (and the courage) to convince Hitler to cancel the whole Plan Z altogether as in the wartime Germany simply could not afford it.

Only two H-39 hulls were laid down and material for the other four ships had started to be assembled in preparation to begin construction but no work had been done.

Plan Z called for the construction of ten battleships (four were actually constructed), three battle cruisers (0), four aircraft carriers (0), twenty heavy cruisers of two different designs (0), thirteen light cruisers (6), twenty-two scout ships – essentially large destroyers (0), sixty-eight destroyers (30) and ninety torpedo boats (36).

This armada (planned to be completed by 1948), had two key objectives – (1) attack and destroy British merchant ships thus effectively enforcing the blockade of Britain – sort of a delayed revenge for the Blockade of Germany during World War I; and (2) engage and destroy the military ships of the Royal Navy thus preventing the latter from establishing and enforcing the Blockade 2.0.

There were several problems with these objectives that rendered them both completely wrong and totally unrealistic.

First, Plan Z was intended to close the gap between Kriegsmarine and the Royal navy and thus had an implicit assumption that the British will do nothing while the Nazi Germany was closing this gap. Nothing could be further from the truth.

In reality, Royal Navy engineering and shipbuilding facilities were so far superior to the German ones that it would have guaranteed that this gap would widen, not shrink.

Second, Hitler and his Kriegsmarine were preparing for the previous war. Consequently, they believed that both abovementioned objectives would be achieved primarily by artillery ships (battleships and cruisers) only supported by aircraft carriers.

However, the battles in the Pacific proved beyond the reasonable doubt that the naval battles of WW2 will be fought between aircraft carrier groups at a distance of dozens (if not hundreds) miles away from each other with the only weapons used being carrier-based aircraft (fighters, level- and dive-bombers, torpedo bombers and recon aircraft) and AA guns (of which ships carried hundreds).

Every carrier group obviously centered around one or more carriers and included cruisers and destroyers that protected the carriers from enemy aircraft and surface ships. Battleships thus were rapidly becoming a thing of the past used mostly to support amphibian assault operations.

And given that merchant convoys would be inevitably protected by escort carriers, the carrier group was the only efficient weapon against these targets as well.

Third, World War II proved beyond the reasonable doubt that both U-boats and surface raiders were highly inefficient against Allied convoys and that life expectancy of a surface raider was not very long.

One of such proofs was delivered by the Battle of the Barents Sea – a naval engagement on 31 December 1942 between warships of the Nazi German Kriegsmarine and British ships escorting convoy JW 51B to Kola Inlet in the USSR.

The action took place (obviously) in the Barents Sea north of North Cape, Norway. The German raiders’ failure to inflict significant losses on the convoy infuriated Hitler, who ordered that German naval strategy would concentrate on the U-boat fleet rather than surface ships.

Other surface raiders fared not much better with just about all of them sunk or forced to return to their home ports where they were subsequently destroyed by air raids or acts of sabotage committed by Allied special forces.

Fourth, much hyped “Battle of Atlantic” between Kriegsmarine U-boats and Allied escort ships and aircraft, in reality, had practically no effect on the course of the Second World War.

At no time during the campaign were supply lines to Britain interrupted; even during the “Bismarck crisis”, convoys sailed as usual (although with heavier escorts). Severe losses incurred by the infamous PQ-17 convoy (two thirds of the total cargo were lost to German aircraft and subs) were only one success that the Kriegsmarine managed to achieve.

In all, during the Atlantic Campaign only 10% of transatlantic convoys that sailed were attacked, and of those attacked only 10% on average of the ships were lost. Overall, more than 99% of all ships sailing to and from the British Isles during World War II did so successfully.

Despite their efforts (and loss of three out of its submariners), the Kriegsmarine failed to prevent the build-up of Allied invasion forces for the invasion of Europe. In November 1942, at the height of the Atlantic campaign, the US Navy escorted the Operation Torch invasion fleet 4,800 km across the Atlantic without hindrance, or even being detected. In 1943 and 1944 the Allies transported some three million American and Allied servicemen across the Atlantic without any significant loss.

Which means that even if Kriegsmarine sunk ten times more ships than it actually did (e.g. by constructing U-boats instead of surface ships, using more long range recon and bomber aircraft such as FW-200 or deploying Type XXI submarines in 1942 instead of 1945), it still would not have produced any significant impact on the course of the war.

And, finally, neither of the two abovementioned objectives (destruction of the merchant convoys and victory over the Royal Navy) was the correct one. The correct objective was to force Britain to either surrender or at least to accept peace terms dictated by Adolf Hitler.

Which could not have been possible to achieve by winning the war at sea (Royal Navy always was and always would have been far superior to Kriegsmarine) or in the air as Luftwaffe simply did not have aircraft (strategic bombers) capable of inflicting a devastating damage on British military and civilian targets.

Even after the defeat of the Soviet Union it would not have had sufficient number of these aircraft for many years. For these two reasons successful amphibious assault (Seelöwe) was simply not possible.

Consequently, the only way to force Britain to surrender was to develop a nuclear bomb and the delivery system (Ho-XVIII – type high-altitude jet bomber undetectable and invincible by British air defenses). And to drop it on London – with the threat of doing the same damage to all British cities in a very short time.

Consequently, the H-Class battleship program, the whole Plan Z (and the whole Nazi Kriegsmarine ship construction program) was a colossal waste of precious resources. Cut and dry, plain and simple, loud and clear.

 

Type XI was more than a U-boat. Much more. It was in fact a U-cruiser. With a submerged displacement of 4,650 tons, six torpedo tubes and a gun armament of four 128-mm guns in two twin gun turrets it would have been the heaviest-armed U-boat and the second-largest (after the Japanese I-400 series). Like the latter, it would have carried a collapsible floatplane – Arado Ar 231 (for long-range recon missions).

The idea behind the development of Type XI was understandable – to remedy the key deficiency of Type VII (the standard U-boat of Kriegsmarine) – its weak gun armament that made it (when surfaced) an easy prey for convoy escort ships (corvettes and the like).

A “wolfpack” of several Type XI U-cruisers had the ability to destroy not only the merchant ships, but escort vessels as well thus annihilating entire convoys (something that the “wolfpack” of Type VII subs could not do).

There was a major problem with this idea, however. The problem that could be expressed in just two words – escort carrier. Escort aircraft carrier that is. Although Type XI boats were supposed to carry formidable anti-aircraft armament as well (two 37-mm and two 20-mm autocannons), it was no match for a squadron of 25-30 anti-submarine aircraft carried by just one such vessel.

Consequently, had these impressive submarines been constructed and put to sea, they would have been inevitably sunk by escort carrier-based aircraft. And rather sooner than later. And the resources used to construct these boats would have been completely wasted.

Fortunately, only four Type XI U-boats (U-112, U-113, U-114, and U-115) were laid down in 1939, and (thankfully) cancelled at the outbreak of World War II. And Kriegsmarine would have been much better off had they concentrated on the next-generation Type XXI subs as soon as possible – these could have been a real game changer due to its high speed, advanced sonar, snorkel and other key features.

 

Type XXI and XXIII U-boats were a next generation of German diesel-electric Elektroboot (“electric boat”) submarines designed and deployed by Nazi Germany during the Second World War. Type XXI were large ocean-going submarines and Type XXIII were small coastal submarines designed to operate in the shallow waters of the North Sea, Black Sea and Mediterranean Sea, where larger Type XXI Elektro boats were at risk i

Although only four of the Type XXI submarines were completed during the war, and only two were sent for combat patrol (and these were not used in combat), Type XXI and XXIII revolutionized the submarine design.

After the war, several navies obtained XXIs and operated them for decades in various roles, and large navies introduced new submarine designs based on them. These include the Soviet Whiskey, US Tang, UK Porpoise, and Swedish Hajen classes, all based on the Type XXI design to a significant extent.

Type XXI and XXIII U-boats were the first submarines designed to operate primarily submerged, rather than spending most of their time as surface ships that could submerge for brief periods as a means to escape detection or to attack.

These subs incorporated a large number of batteries to increase the time they could spend underwater, to as much as several days, and they only needed to surface to periscope depth for recharging via a snorkel.

The new U-boat design included many general improvements as well; much greater underwater speed by an improved hull design, greatly improved diving times, power-assisted torpedo reloading, and greatly improved crew accommodations.

All six bow torpedo tubes could be reloaded faster than a Type VIIC could reload one tube. Consequently, Type XXI submarine could fire 18 torpedoes in less than 20 minutes. It also featured a very sensitive passive sonar for the time, housed in the “chin” of the hull.