Kreuzer P Class
Encyclopedia
The P class was a German Navy
group of twelve heavy cruiser
s; they were the successor to the Deutschland class
cruisers. Design work began in 1937 and continued until 1939; at least nine designs were considered. The final design was armed with six 28 cm (11 in) quick-firing guns in two triple turrets, as in the preceding Deutschland class. The ships were designated as Panzerschiff (armored ship), and given the preliminary names P1–P12. They were an improved design over the preceding planned D 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already assigned to shipyards, construction never began on the P class ships after the O class battlecruiser design superseded them.
began a rearmament program in Germany. He signed the Anglo-German Naval Agreement
, which allowed Germany to build up its navy to 35 percent of the strength of the British Royal Navy
and effectively repudiated the restrictions of the Treaty of Versailles
on the German fleet. This led to a decision in 1937 to build ships to an improved design. Design work on the new class of armored ships began that year. After more than twenty designs were considered to meet the navy's specifications, one was chosen; it was designated as cruiser "P". It called for a 20000 tonnes (19,684.1 LT) with a maximum speed of 34 knot, armed with six 28 cm (11 in) guns in two triple turrets
.
By 1938, it became clear to Admiral Erich 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 for Plan Z
, which included twelve ships of the "P" class design. The design work on the new ships proceeded in parallel with work on the O class battlecruiser design. 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.
Many problems were encountered with designing the ships, the most prevalent being armor. The required maximum speed of 34 kn (18.5 m/s) meant that the minimum length had to grow from the original 217 m (711.9 ft) to 229.5 m (753 ft). It also meant that the beam
could be a minimum of 25 m (82 ft)—unless diesel engine
s, like those used in the Deutschlands, were desired; they would increase the beam by 2 m (6.6 ft). Unfortunately for the designers, the widened beam meant that an even longer hull was needed to maintain hydrodynamic efficiency. All of this complicated the armor arrangements, as more armor was needed to cover the longer length and widened beam. Eventually it was deemed that it was impossible to include diesel power on a 20000 tonnes (19,684.1 LT) displacement
.
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, including Deutsche Werke
in Kiel
, Blohm & Voss in Hamburg
, and the KM Dockyard
in Wilhelmshaven
. 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 Feb 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.
, and 230 m (754.6 ft) overall. The ships had a beam
of 26 m (85.3 ft) and a designed draft
of 7.2 m (23.6 ft); the maximum draft was 8 m (26.2 ft). They were to have incorporated longitudinal frame stringer steel construction, and would have been primarily welded. The ships would have had thirteen watertight compartments and a transom stern. The ships were equipped with two catapults and two Arado 196
seaplane
s. The armor layout was to have used Krupp cemented steel, but the design was not complete; only broad requirements are known. The main armored deck was 70 mm (2.8 in) thick, with 100 mm (3.9 in)–thick sloping deck armor. The upper deck was 20 mm (0.78740157480315 in) thick. The two main-battery barbettes had armor protection that ranged between 80 mm (3.1 in) and 100 mm (3.9 in) thick. The armored 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, and had a depth of 14.2 m (46.6 ft).
The ships were designed to be equipped with twelve MAN 9-cylinder V-configuration double acting two-stroke diesel engines that were designed to provide a total of 165,000 shaft horsepower at 250 rpm
. The engines were arranged in four sets of three, each of which drove one of four shafts. The shafts each turned a screw
that was 4.3 m in diameter. The ships were designed to carry 3600 tonnes (3,543.1 LT) of fuel oil, but were capable of storing up to 5000 t (4,921 LT). At a cruising speed of 13 knots, this enabled a maximum range of 25,000 nautical miles; at 19 knots, the range was reduced to 15,000 nmi.
The ships were armed with six 28 cm (11 in) quick-firing guns mounted in two triple turrets, one fore and one aft. It is not known if these were to have been the same 28 cm SK C/28 guns
as the preceding Deutschland class cruisers, or a different design. The ships were also armed with 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. The 15 cm twin turrets were Drh L. C/34 mounts—the same type as those fitted to the and Scharnhorst 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 22000 m (24,059.5 yd). The 15 cm guns had a rate of fire of between 6 to 8 45.3 kg (99.9 lb) rounds per minute, at a muzzle 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 (51.8 lb) main charge in a brass cartridge.
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. The 10.5 cm guns fired two types of projectiles: a 58.4 kg (128.7 lb) high explosive shell and a 51.8 kg (114.2 lb) incendiary round. Both types of ammunition used a single propellant charge: the 11.46 kg (25.3 lb) RPC/32 charge. The guns could elevate to 80 degrees, and could hit targets 12500 m (13,670.2 yd) away. The ships were also armed with six 53.3 cm (21 in) submerged torpedo tubes.
Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...
group of twelve heavy cruiser
Heavy cruiser
The heavy cruiser was a type of cruiser, a naval warship designed for long range, high speed and an armament of naval guns roughly 203mm calibre . The heavy cruiser can be seen as a lineage of ship design from 1915 until 1945, although the term 'heavy cruiser' only came into formal use in 1930...
s; they were the successor to the Deutschland class
Deutschland class cruiser
The Deutschland class was a series of three panzerschiffe , a form of heavily armed cruiser, built by the Reichsmarine officially in accordance with restrictions imposed by the Treaty of Versailles...
cruisers. Design work began in 1937 and continued until 1939; at least nine designs were considered. The final design was armed with six 28 cm (11 in) quick-firing guns in two triple turrets, as in the preceding Deutschland class. The ships were designated as Panzerschiff (armored ship), and given the preliminary names P1–P12. They were an improved design over the preceding planned D class cruisers
D class cruiser (Germany)
The D class cruisers were a pair of cruisers, classified as Panzerschiffe by the Kriegsmarine. The ships were improved versions of the preceding s, authorized by Adolf Hitler in 1933. They were intended to counter a new French naval construction program...
, which had been canceled in 1934. Although the ships were already assigned to shipyards, construction never began on the P class ships after the O class battlecruiser design superseded them.
Design
In the early 1930s, Adolf HitlerAdolf Hitler
Adolf Hitler was an Austrian-born German politician and the leader of the National Socialist German Workers Party , commonly referred to as the Nazi Party). He was Chancellor of Germany from 1933 to 1945, and head of state from 1934 to 1945...
began a rearmament program in Germany. He signed the Anglo-German Naval Agreement
Anglo-German Naval Agreement
The Anglo-German Naval Agreement of June 18, 1935 was a bilateral agreement between the United Kingdom and German Reich regulating the size of the Kriegsmarine in relation to the Royal Navy. The A.G.N.A fixed a ratio whereby the total tonnage of the Kriegsmarine was to be 35% of the total tonnage...
, which allowed Germany to build up its navy to 35 percent of the strength of the British Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
and effectively repudiated the restrictions of the Treaty of Versailles
Treaty of Versailles
The Treaty of Versailles was one of the peace treaties at the end of World War I. It ended the state of war between Germany and the Allied Powers. It was signed on 28 June 1919, exactly five years after the assassination of Archduke Franz Ferdinand. The other Central Powers on the German side of...
on the German fleet. This led to a decision in 1937 to build ships to an improved design. Design work on the new class of armored ships began that year. After more than twenty designs were considered to meet the navy's specifications, one was chosen; it was designated as cruiser "P". It called for a 20000 tonnes (19,684.1 LT) with a maximum speed of 34 knot, armed with six 28 cm (11 in) guns in two triple turrets
Gun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
.
By 1938, it became clear to Admiral Erich Raeder
Erich Raeder
Erich Johann Albert Raeder was a naval leader in Germany before and during World War II. Raeder attained the highest possible naval rank—that of Großadmiral — in 1939, becoming the first person to hold that rank since Alfred von Tirpitz...
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 for Plan Z
Plan Z
Plan Z was the name given to the planned re-equipment and expansion of the Nazi German Navy ordered by Adolf Hitler on January 27, 1939...
, which included twelve ships of the "P" class design. The design work on the new ships proceeded in parallel with work on the O class battlecruiser design. 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.
Many problems were encountered with designing the ships, the most prevalent being armor. The required maximum speed of 34 kn (18.5 m/s) meant that the minimum length had to grow from the original 217 m (711.9 ft) to 229.5 m (753 ft). It also meant that the beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
could be a minimum of 25 m (82 ft)—unless diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s, like those used in the Deutschlands, were desired; they would increase the beam by 2 m (6.6 ft). Unfortunately for the designers, the widened beam meant that an even longer hull was needed to maintain hydrodynamic efficiency. All of this complicated the armor arrangements, as more armor was needed to cover the longer length and widened beam. Eventually it was deemed that it was impossible to include diesel power on a 20000 tonnes (19,684.1 LT) displacement
Displacement (ship)
A ship's displacement is its weight at any given time, generally expressed in metric tons or long tons. The term is often used to mean the ship's weight when it is loaded to its maximum capacity. A number of synonymous terms exist for this maximum weight, such as loaded displacement, full load...
.
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, including Deutsche Werke
Deutsche Werke
Deutsche Werke was a German shipbuilding company founded in 1925 when Kaiserliche Werft Kiel and other shipyards were merged. It came as a result of the Treaty of Versailles after World War I that forced the German defence industry to shrink...
in Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
, Blohm & Voss in Hamburg
Hamburg
-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...
, and the KM Dockyard
Kriegsmarinewerft Wilhelmshaven
Kriegsmarinewerft Wilhelmshaven was the naval shipyard in Wilhelmshaven, Prussian Hanover, between 1918 and 1945 in the German Navy's extensive base located there.-History:...
in Wilhelmshaven
Wilhelmshaven
Wilhelmshaven is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea.-History:...
. 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 Feb 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.
Characteristics
The P class ships were 223 m (731.6 ft) long at the waterlineWaterline length
The Waterline length is a measurement of ships and boats. The term denotes the length of the vessel at the point where it sits in the water. It excludes the total length of the boat, such as features that are out of the water...
, and 230 m (754.6 ft) overall. The ships had a beam
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
of 26 m (85.3 ft) and a designed draft
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...
of 7.2 m (23.6 ft); the maximum draft was 8 m (26.2 ft). They were to have incorporated longitudinal frame stringer steel construction, and would have been primarily welded. The ships would have had thirteen watertight compartments and a transom stern. The ships were equipped with two catapults and two Arado 196
Arado Ar 196
-See also:-Bibliography:* Dabrowski, Hans-Peter and Koos, Volker. Arado Ar 196, Germany's Multi-Purpose Seaplane. Atglen, PA: Schiffer Military History, 1993. ISBN 0-88740-481-2....
seaplane
Seaplane
A seaplane is a fixed-wing aircraft capable of taking off and landing on water. Seaplanes that can also take off and land on airfields are a subclass called amphibian aircraft...
s. The armor layout was to have used Krupp cemented steel, but the design was not complete; only broad requirements are known. The main armored deck was 70 mm (2.8 in) thick, with 100 mm (3.9 in)–thick sloping deck armor. The upper deck was 20 mm (0.78740157480315 in) thick. The two main-battery barbettes had armor protection that ranged between 80 mm (3.1 in) and 100 mm (3.9 in) thick. The armored 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, and had a depth of 14.2 m (46.6 ft).
The ships were designed to be equipped with twelve MAN 9-cylinder V-configuration double acting two-stroke diesel engines that were designed to provide a total of 165,000 shaft horsepower at 250 rpm
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...
. The engines were arranged in four sets of three, each of which drove one of four shafts. The shafts each turned a screw
Propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...
that was 4.3 m in diameter. The ships were designed to carry 3600 tonnes (3,543.1 LT) of fuel oil, but were capable of storing up to 5000 t (4,921 LT). At a cruising speed of 13 knots, this enabled a maximum range of 25,000 nautical miles; at 19 knots, the range was reduced to 15,000 nmi.
The ships were armed with six 28 cm (11 in) quick-firing guns mounted in two triple turrets, one fore and one aft. It is not known if these were to have been the same 28 cm SK C/28 guns
28 cm SK C/28 naval gun
The German 28 cm C/28 naval gun was a 283 mm 52-caliber built-up gun designed in 1928 used on the Deutschland class "pocket battleships".-History:-Characteristics:...
as the preceding Deutschland class cruisers, or a different design. The ships were also armed with 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. The 15 cm twin turrets were Drh L. C/34 mounts—the same type as those fitted to the and Scharnhorst 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 22000 m (24,059.5 yd). The 15 cm guns had a rate of fire of between 6 to 8 45.3 kg (99.9 lb) rounds per minute, at a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
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 (51.8 lb) main charge in a brass cartridge.
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. The 10.5 cm guns fired two types of projectiles: a 58.4 kg (128.7 lb) high explosive shell and a 51.8 kg (114.2 lb) incendiary round. Both types of ammunition used a single propellant charge: the 11.46 kg (25.3 lb) RPC/32 charge. The guns could elevate to 80 degrees, and could hit targets 12500 m (13,670.2 yd) away. The ships were also armed with six 53.3 cm (21 in) submerged torpedo tubes.