H-class battleship proposals

Class overview
Preceded by	H class battleship (1939)
Completed	0
General characteristics
Displacement	110,696 tonnes design 131,088 tonnes fully laden
Length	345.1 m (1,132 ft 3 in) (waterline) 359 m (1,177 ft 10 in) (overall)
Beam	51.5 m (169 ft 0 in)
Draft	12.7 m (41 ft 8 in) design 13.5 m (44 ft 3 in) fully loaded
Propulsion	Inner shafts: 8 × 9-cylinder MAN diesel engines, 120,000 shp Outer shafts: 2 × steam turbines driven by 6 oil-fired boilers, 150,000 shp Combined power: 4 shafts, 270,000 shp
Speed	30.1 knots (55.7 km/h) maximum
Range	20,000 nautical miles (37,000 km) at 19 knots (35 km/h)
Complement	Unknown, but not less than 2,600
Sensors and processing systems	Radar included, but not specified
Armament	8 × 50.8 cm (20.0 in) guns in twin turrets 12 × 15 cm (5.9 in) guns in twin turrets 16 × 10.5 cm (4.1 in) in twin turrets 28 × 37 mm (1.5 in) in twin mounts 40 × 20 mm (0.79 in) in quadruple mounts 6 × 533 mm (21.0 in) underwater torpedo tubes
Armor	Belt: 380 mm (15 in) Armoured decks: 60 mm (2.4 in) top deck 140 mm (5.5 in) upper AD 130 mm (5.1 in)–200 mm (7.9 in) lower AD Torpedo bulkheads: 45 mm (1.8 in) outer 30 mm (1.2 in) inner (depth of 11 m (36 ft 1 in))
Aircraft carried	one catapult with nine aircraft, probably Arado 196 seaplanes

The H-44 class was the ultimate evolution of a series of battleship design studies, derived by the Third Reich's Kriegsmarine as an outgrowth of the H-Class battleship program.

The H-39 design

The H-Class ships saw their design finalized by 1939, intended to be the mainstay of Kriegsmarine's Plan Z. They essentially represented an enlarged and refined Bismarck class, armed with 40.6 cm guns, revised armour configurations, and diesel machinery. Six ships were contemplated, all to be commissioned by 1944, which in turn necessitated that construction begin in 1939. However, by the 10th of October 1939, construction (which had only commenced on the first two vessels) was halted to make room for expansion of the U-Boat fleet, as the onset of the World War II undid the Kriegsmarine's prewar strategy.

Despite the stoppage order (and the scrapping of the vessels, which began in 1940), the Kriegsmarine's design office continued work on battleship development. Their goal was to assess the characteristics required of future battleship designs, with the understanding that a new construction program could commence after the end of the war in Europe. These design studies, which grew out of the original design (dubbed H-39) took special note of the wartime experiences of the Kriegsmarine's dreadnoughts. The experiences of the Bismarck had a particularly strong influence on the work of the design office. The H-44 was the final design of this series, and its characteristics are those reprinted in the adjacent table.

Design escalation

Adolf Hitler was always notable for his megalomania, from the reconstruction of Berlin to his interest in the Maus super-tank, and naval affairs were no exception. He sought the construction of the largest possible surface warships, and only the practical advice of Grand Admiral Erich Raeder and Admiral Werner Fuchs backed him down from a notion to arm the H-Class ships with the largest naval rifles ever conceived. Nevertheless, the notion of particularly large super-dreadnoughts remained in the forefront of German naval design.

A second factor to explain the eventual H-44 study is the nature of military design, where design compromises lend themselves to escalation. For example, the designer might want to increase defensive protection (armour). This increases weight, which leads to the need for increased power (to maintain speed and range), necessitating larger engines. This, in turn, leads to a larger hull, which then requires more armour to protect the greater volume, leading to more weight, and so the cycle continues. The design of the United States Navy's Montana-class battleships is an excellent illustration of this principle.

The first step in this process began in 1940, when the construction suspension allowed the design office to examine ways of improving the armour protection of the basic H-Class. Two designs were considered (dubbed "A" and "B"), one of which reduced the main battery from four twin turrets to three, and the other which retained the original battery, but was substantially enlarged to provide increased protection. Since the increased weight necessitated more shaft horsepower to maintain speed, the design office chose to switch to a mixed powerplant of marine diesels supplemented by steam turbines, now driving four shafts instead of three. These designs, however, were unofficial studies, and did not significantly directly contribute to the design chain that progress from the H-41 to the H-44 designs.

In 1941, the Oberkommando der Kriegsmarine (OKM) directed the design office to formally examine the characteristics required of the next generation of battleships, combining a top speed of 30 knots (56 km/h) with armour heavy enough to match expected opposition and commensurate firepower. This led to the H-41 design. With increased horizontal armour, deeper torpedo bulkhead protection, and new larger-bore 42 cm main cannons, this design required the mixed propulsion system of the 1940 designs, but retained a three-shaft setup. The H-41 design was of a size approximately equivalent to the Japanese Yamato-class, displacing nearly 75,000 tons full load and reaching a length of 275 metres.

After the loss of the Bismarck, the problem of vulnerability to air attack was re-examined. A new series of modifications to H-41 was drafted, which attempted to remedy the vulnerability of propellers and rudders to torpedo attack; the 1941 bombing attacks against the Scharnhorst also informed these design changes. Some were incorporated into H-41, but soon a revised design, H-42, was developed instead. It now used a four-shaft setup, with shrouding to protect the propeller skegs, and multiple rudders aligned with the shafts to provide manoeuvering redundancy in the event of attack. Increasing displacement led to a deeper draft, complicating construction and operation of these vessels; OKM accepted these changes, despite the shallow depth of much of the North Sea, because they assumed that large new bases would be built along the Atlantic coast, especially in Norway, giving the massive ships deepwater access. The H-42 was still considered to be the design characteristics of the next battleship class, whose construction (still labelled H-Class) would commence after hostilities ended. However, H-42 already had become a far more massive ship than its predecessors; along with a great stiffening of the horizontal and vertical protection against shellfire, anti-torpedo protection increased through a new multiple-bulkhead system nearly 1.5 metres wider, in total, than that of H-41.. This design, 305 metres long and with a beam of nearly 43 m, would displace 98,000 tons full load; this ship would have been the size of a modern nuclear-powered supercarrier.

After the H-42, the designs grew even more unfeasible. In order to defeat all possible adversaries, the main battery was increased to a bore of 50.8 cm, one of the largest guns ever considered for seaborne duty; no such weapon had been designed. However, the mixed-calibre secondary batteries, which had so failed the Bismarck on her maiden sortie, were unchanged in number or configuration. Only 37 mm and 20 mm weapons were augmented, but their effectiveness was quite limited against air attack. The new H-43 was no longer a serious design proposal; German yards would have been extremely hard-pressed to build them, and operating them in any confined waters would have been enormously hazardous. It merely illustrated the possibilities, given no constraints. In this way, it (and the final H-44 design) resembled the Tillman "maximum battleship" studies of the U.S. Navy in 1916.

The final H-44 design

The H-44 was the last of these large battleship studies, and it demonstrates the escalating demands, especially in armour, necessitated by the revolution in aerial warfare that accompanied the Second World War. Threats from torpedo attack were clearly a high priority; the H-44 featured a multiple-bulkhead defense whose transverse depth reached 11 metres (twice that of the Bismarck); the increased depth of this system was the main change relative to the H-43. Enhancements to upper-deck splinter protection, along with the multiple armoured decks, demonstrated a recognition of the threat posed by large aircraft bombs, such as those used to sink the Tirpitz in April 1944. However, even the H-44 could not have withstood such weapons. Like the H-43, it also used a triple bottom to protect against mine damage. Increased compartmentalization improved the watertight characteristics further.

The four-shaft mixed propulsion system offered the same power as the H-42 and H-43, but the increased size of the H-44 compromised performance. Top speed fell from 32 knots (59 km/h) in the H-42 to 30 in the H-44, but this was deemed to be adequate by OKM. Endurance remained the same: 20,000 nautical miles (40,000 km) at 19 knots (35 km/h).

The armament of the H-44 was identical to that of the H-43; eight 50.8 cm guns in four turrets, two fore and two aft. The mixed-calibre secondary battery, typical of Axis capital ship designs, was identical in layout to that of the Bismarck-class. Smaller anti-aircraft weapons were more numerous: 28 37 mm barrels were disposed in twin mounts, while 10 quadruple mounts for 20 mm autocannons were provided. The increased bulk of the H-44 allowed a larger hanger, permitting the carriage of 9 seaplanes.

The end result of all of the design studies had been reached; no further battleship designs were contemplated by the Third Reich. The H-44 demonstrates the almost exponential growth of warship designs in the face of changing realities. Compared to the original H-39 design, the H-44 was 126 percent heavier, nearly 30 percent longer, and more than 38 percent beamier.

See also

• Tillman Maximum Battleships
• Japanese A-150 battleship design