| Class overview | |
|---|---|
| Operators |  Kriegsmarine |
| Preceded by | D-class cruiser (planned) |
| Succeeded by | Admiral Hipper class |
| Planned | 12 |
| Completed | 0 |
| General characteristics | |
| Type | Heavy cruiser |
| Displacement | |
| Length | |
| Beam | 26 m (85 ft 4 in) |
| Draft | 7.20 m (23 ft 7 in) |
| Installed power | 165,000 PS (163,000 shp) |
| Propulsion | 12 ×diesel engines |
| Speed | 33knots (61 km/h; 38 mph) |
| Range | 25,000 nmi (46,000 km; 29,000 mi) at 13 knots (24 km/h; 15 mph) |
| Armament |
|
| Armor |
|
| Aircraft carried | 2 ×Arado 196 seaplanes |
| Aviation facilities | 2 × steamcatapults |
TheP class was a planned group of twelveheavy cruisers of Nazi Germany'sKriegsmarine; they were the successor to theDeutschland-class cruisers. Design work began in 1937 and continued until 1939; at least twenty designs were submitted with nine of them being considered. There were three designs that were selected as the final contenders. One design was armed with six 283mm main guns in one triple turret forward and one more turret aft. It had two 150mm double secondary gun turrets as secondary armament with one being positioned above and just fore of the aft of the main 283mm main turret, and the other being in front and lower of the front main gun turret. This design had more beam than the other 2 designs. It also mounted 2 seaplanes on its fantail instead of the mid ship area. The final design was armed with six 28 cm (11 in) quick-firing guns in two triple turrets, as in the precedingDeutschland class. The ships were designated asPanzerschiff (armored ship), and given the preliminary names P1–P12. They were an improved design over the preceding plannedD-class cruisers, which had been canceled in 1934. Although the ships were already assigned to shipyards, construction never began on the P-class ships after theO-class battlecruiser design superseded them.
In the early 1930s,Adolf Hitler began a rearmament program in Germany. He signed theAnglo-German Naval Agreement in 1935, which allowed Germany to build up its navy to 35 percent of the strength of the BritishRoyal Navy and effectively repudiated the restrictions of theTreaty of Versailles on the German fleet.[1] This led to a decision in 1937 to build ships to an improvedDeutschland-class cruiser design, which were at that time classified as "panzerschiff" (armored ship).[2] Design work on the new class of armored ships began that year.[3] After more than twenty designs were evaluated to meet the navy's specifications, one was chosen; it was designated as cruiser "P".[2] It called for a ship thatdisplaced 20,000-metric-ton (19,684-long-ton), which had a maximum speed of 34 to 35knots (63 to 65 km/h; 39 to 40 mph), and was armed with amain battery of six 28 cm (11 in) guns in two tripleturrets.[4]
By 1938, it became clear to AdmiralErich Raeder that Hitler's aggressive foreign policy would bring conflict with Britain. He therefore decided that a significantly larger force of armored ships would be necessary to execute an effective commerce raiding campaign against the British. Raeder's intention to fight a commerce war against Britain was the basis forPlan Z,[1] which included twelve ships of the P-class design.[2] The design work on the new ships proceeded in parallel with work on theO-class battlecruiser design.[5] Experiments were conducted on at least nine different design proposals between March 1938 and December 1939. The designs varied somewhat in terms of dimensions as well as armament; some of the designs featured three 28 cm triple turrets.[3]
Many problems were encountered with designing the ships, the most prevalent being armor. The required maximum speed of 34 kn (63 km/h; 39 mph) meant that the minimumlength had to grow from the original 217 m (711 ft 11 in) to 229.50 m (752 ft 11 in). It also meant that thebeam could be a minimum of 25 m (82 ft)—unlessdiesel engines, like those used in theDeutschland's, were desired; they would increase the beam by 2 m (6 ft 7 in). Unfortunately for the designers, the widened beam meant that an even longerhull was needed to maintain hydrodynamic efficiency. All of this complicated the armor arrangements, as more armor was needed to cover the hull as it grew in size. Eventually it was deemed that it was impossible to include diesel power on a 20,000-metric-ton displacement. The displacement limit was therefore increased to accommodate diesel engines.[6]
Initially, twelve ships were ordered based on the P-class design. The ships were ordered under the provisional names P1 through P12; the contracts were awarded to a number of German shipyards, includingDeutsche Werke inKiel,Blohm & Voss inHamburg, and theKriegsmarinewerft inWilhelmshaven. However, Plan Z was reduced in size, and the number of armored ships was pared down to only eight vessels. This caused several of the contracts to be shifted around amongst the various shipbuilding companies. The first keel was set to be laid on 1 February 1940. The revised version of Plan Z, approved on 27 July 1939, removed the P-class ships from the construction queue. Instead, the decision was made to build the O-class battlecruisers only, with the outbreak ofWorld War II in September meaning that not even those vessels would be built.[3]
The P-class ships were to have been 223 m (731 ft 8 in) longat the waterline, and 230 m (754 ft 7 in) overall. The ships would have had a beam of 26 m (85 ft 4 in) and a designeddraft of 7.20 m (23 ft 7 in); the maximum draft was to be 8 m (26 ft 3 in). The design featured a very longforecastle deck that extended for most of the length of the hull, terminating just forward of the aft main battery turret. They were to have incorporatedlongitudinal frame stringer steel construction, and would have been primarilywelded to save weight. The ships would have had thirteenwatertight compartments and atransom stern. The forwardsuperstructure consisted of a large, armoredconning tower with a heavy tower mast; a smaller secondary conning tower with a pole mast was located further aft. The ships were to have been equipped with twocatapults on thequarterdeck, arranged side-by-side, perpendicular to thecenterline. Each catapult carried anArado 196seaplane.[7]
The ships were designed to be equipped with twelve MAN 9-cylinder V-configuration double acting two-stroke diesel engines, which were arranged in four sets of three, each of which drove one of four shafts. The shafts each turned ascrew that was 4.3 m (14 ft) in diameter. Smoke from the diesels would have been vented through a pair of largefunnelsamidships. The propulsion system was rated to produce a top speed of 33 knots (61 km/h; 38 mph) from 165,000metric horsepower (163,000 shp). The ships were designed to carry 3,600 metric tons (3,500 long tons) of fuel oil, but were capable of storing up to 5,000 t (4,900 long tons). At a cruising speed of 13 knots (24 km/h; 15 mph), this enabled a maximum range of 25,000nautical miles (46,000 km; 29,000 mi); at 19 knots (35 km/h; 22 mph), the range was reduced to 15,000 nmi (28,000 km; 17,000 mi).[3]
The ships were armed with a main battery of six 28 cm (11 in) quick-firing guns mounted in two triple turrets, one fore and one aft on the centerline. It is not known if these were to have been the same28 cm SK C/28 guns as the precedingDeutschland-class cruisers, or the28 cm SK C/34 guns used by theScharnhorst-class battleships. The ships were also armed with asecondary battery of four 15 cm (5.9 in)/L55 guns in two twin turrets, also mounted on the centerline, fore and aft. The fore 28 cm turret would have been superfiring over the fore 15 cm turret; the layout was reversed for the aft pair of turrets.[3] The 15 cm twin turrets were C/34 mounts—the same type as those fitted to theBismarck- andScharnhorst-class battleships, as well as a number of other designs. The turrets allowed depression to −10 degrees and elevation to 40 degrees, which enabled a maximum range of 22,000 m (24,000 yd). The 15 cm guns had a rate of fire of between 6 and 8 45.3 kg (100 lb) rounds per minute, at amuzzle velocity of 875 meters per second (2,871 ft/s). The guns used two propellant charges: a 14.15 kg (31.2 lb) RPC/38 fore charge and a 23.5 kg (52 lb) main charge in a brass cartridge.[8]
The P-class ships were to have mounted a fairly small anti-aircraft battery: four 10.5 cm (4.1 in)/L65 high-angle guns and four 3.7 cm (1.5 in) Flak guns.[3] The 10.5 cm guns were carried in four twin turrets, one pair abreast the forward conning tower and the other on either side of the rear funnel. These guns fired two types of projectiles: a 15.1 kg (33 lb)high explosive shell and a 15.8 kg (35 lb) incendiary round. Both types of ammunition used a single propellant charge: the 5.2 kg (11 lb) RPC/32 charge. The guns could elevate to 80 degrees, and could hit targets 12,500 m (13,700 yd) away.[9] The ships were also armed with six 53.3 cm (21 in) submergedtorpedo tubes.[3]
The armor layout was to have usedKrupp cemented steel, but the design was not complete; only broad requirements are known. The main armored deck was 70 mm (2.8 in) thick on the flat, with 100 mm (3.9 in)–thick plate on sides, where it sloped downward to connect to the bottom of the armor belt. The upper deck was 20 mm (0.79 in) thick. The two main-battery barbettes had armor protection that ranged between 80 mm (3.1 in) and 100 mm thick, and had a depth of 14.20 m (46 ft 7 in). Thearmored belt was 120 mm (4.7 in) thick over the vital areas of the ship, and tapered down to 40 mm (1.6 in) in less critical areas.[7]