Plan Z:
German Armored Cruisers

When Kriegsmarine commander Erich Raeder crafted the building program known as Plan Z, the final version did not involve a lot of subtlety. For a brief moment, the German Navy stood at the top of the intense struggle between feudal-style barons that defined Nazi Germany’s political structure. Raeder had massive political capital, and it would not last long. He had to strike quickly, so rather than choose between his underlings’ competing proposals, he lumped all of them into Plan Z: the advocates of a battle fleet, of a carrier strike force, of a commerce-raiding strategy built around long-range cruisers – all of them would get their toys. The question of how to meld these disparate fleets together into a coherent strategy would be answered later, if at all.

That motley paper fleet that would never come to be is the centerpiece of our Second World War at Sea: Plan Z expansion set. The battleships and the aircraft carriers are all there, and the long-range cruisers, too.

At the top of the commerce-raiding faction’s wish list was an improved version of the Deutschland-class armored cruiser, the so-called “pocket battleship.” The armored cruisers had been designed and laid down under the Weimar Republic, when Raeder’s Great War nemesis Hans Zenker still ran the Navy. Zenker believed that Germany, in her greatly reduced economic circumstances, could not build a fleet to challenge her potential enemies and should instead look to attack their weaknesses such as overseas trade.

Raeder opposed this strategy simply because Zenker supported it. Raeder, the former chief of staff of the High Seas Fleet’s battle cruiser squadron, despised Zenker so thoroughly that he made sure the name of Zenker’s World War One command, his beloved battle cruiser von der Tann, would never appear again on a German warship. But while Raeder had purged the Navy of Zenker’s protégés, the commerce-raiding strategy had many supporters. So Raeder threw them a bone, including a whopping 12 new armored cruisers in Plan Z.

The new armored cruiser would be considerably larger than Deutschland (later re-namedtzow), to give greater speed and even more range. Deutschland had been designed under the restrictions of the Versailles Treaty to a nominal displacement of 10,000 tons (she actually weighed in at a little over 14,000 tons, with her two sisters displacing somewhat more). Diesel engines gave Deutschland enormous range (theoretically almost 20,000 nautical miles, or close to twice that of the similarly-sized but conventionally-powered Hipper class heavy cruisers). But they did not give the ship great speed; Deutschland had a designed speed of 28 knots but in service rarely touched 26, compared to 32 knots for the heavy cruisers).

German propaganda claimed Deutschland to be “faster than the more powerful ships and more powerful than the faster ships” but this was not really true. All of the new fast battleships laid down in the 1930’s could overtake Deutschland, including the relatively slow American North Carolina and even the rebuilt Great War-era Italian battleships like Conte di Cavour.

Launching Deutschland, May 1931.

The new cruiser, given the project designation “P,” would bring that propaganda claim to reality. Designed speed would be 34 knots, faster not only than the more powerful ships but also most of the faster ships, too. And that speed would be delivered once again by a diesel power plant, to assure an even heftier range: 25,000 nautical miles, or enough to steam completely around the world (using the Suez and Panama canals).

MAN (Maschinenfabrik Augsburg-Nürnberg), the supplier of Germany’s big marine diesels, agreed that they could build such an engine, but it would be very large. To make 34 knots the ship would need 165,000 horsepower, making them the most powerful marine engines of any type built in Germany up to that time (a power plant almost identical to that of the H class battleships, which weighed in at almost exactly twice the displacement of the new armored cruiser).

Engines designed for a massive battleship would not fit in a standard cruiser hull. The big diesels took up a width of 19 meters, and design practice called for a separation of at least four meters between engines and hull on either side to allow for underwater protection. Therefore, Cruiser P would have to be wide: 27 meters, compared to 20.7 for Deutschland or 21.3 for Admiral Hipper. To give the ship the long, sleek form needed to make her high speed, she would have to be lengthened: Cruiser P would be 235 meters long, the same as the battle cruiser Scharnhorst. Unusual for German warships, she would have a transom (flattened) stern to help eke out a little more speed.

Adding more length in turn added more displacement, reaching 25,000 tons. And that huge hull would need protection: on paper, at least, a belt 145mm (5.7 inches) thick and an armored deck of 70mm (2.75 inches), with 100mm (3.9 inches) on the main armament’s barbettes and 140mm (5.5 inches) on the turrets. That would be sufficient to protect the ship against the 8-inch shells of enemy heavy cruisers, but Cruiser P would have minimal underwater protection and be exceedingly vulnerable to mines or torpedoes. The thin armored deck would not do much against enemy bombs, either.

Some sources list slightly different specifications; the design bureau produced a number of alternative sketches and these (for the ship depicted in our Plan Z expansion set) are for the December 1938 version which appears to be the mostly likely to have been approved for production.

Like Deutschland, Cruiser P would carry six 280mm (11-inch) guns in two triple turrets; some alternatives called for the six guns to go in three twin turrets, or for four 380mm (15-inch) guns in a pair of twin turrets. In addition she would have four 150mm (5.9-inch) guns in dual turrets mounted in superfiring position behind the main turrets, eight 105mm (4.1-inch) anti-aircraft guns and 20 light anti-aircraft weapons. She would also carry eight torpedo tubes in a pair of quadruple mounts.

The new ship would be extremely fast, long-ranged, poorly-armed for her great size and fantastically easy to sink. She would also likely be enormously expensive, far beyond the budget of Nazi Germany even during the brief window when Plan Z had top priority. Raeder does not seem to have taken the project very seriously: while shipyards were selected for the dozen cruisers, no contracts were ever actually placed and no construction took place. And Germany had no spare slipways to build Cruiser P; all of the shipyards were already at full capacity building other large warships.  Eventually three of the shipyards promised a P-class cruiser received contracts to build a new O-class battle cruiser instead.

Unlike the terribly-designed H-class battleship, the terribly-designed Cruiser P never approached reality. Given Raeder’s disdain for his predecessor’s commerce-raider concept, it’s questionable whether he ever intended for the ship to be built. Raeder did embrace the idea of attacking enemy trade, but insisted that this mission could be carried out by traditional battleships.

Second World War at Sea: Plan Z throws that reality to the winds, including all twelve of the proposed commerce raiders.

Click here to order Second World War at Sea: Plan Z right now.

Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and award-winning journalist, he has published over 100 books, games and articles on historical subjects. He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold. Leopold despises motorcycles.