located. This included the ammunition magazines and the machinery spaces. The belt was reduced in less critical areas, to forward and aft. The belt tapered down to at the bow, though the stern was not protected by armor at all. A torpedo bulkhead ran the length of the hull, several meters behind the main belt. The main armored deck ranged in thickness from 30 mm in less important areas to in the sections that covered the more critical areas of the ship. The forward conning tower was protected with heavy armor: the sides were 300 mm thick and the roof was . The rear conning tower was less well armored; its sides were only , and the roof was covered with of armor plate. The main battery gun turrets were also heavily armored: the turret sides were and the roofs were . The 15 cm guns had 150 mm worth of armor plating in the casemates; the guns themselves had shields to protect their crews from shell splinters. Construction and cancellation Seven ships were originally planned in the class: Mackensen, Graf Spee, Prinz Eitel Friedrich, "A"/Ersatz Friedrich Carl, and three other vessels. The last three ships were redesigned as the , leaving four ships to be built to the Mackensen design. The first two ships were ordered on 14 August 1914, shortly after the outbreak of World War I. Mackensen was funded through the 1914 budget, while funding for Graf Spee came from the war budget. Mackensen—ordered under the provisional name Ersatz Victoria Louise, as a replacement for the old protected cruiser —was named after Generalfeldmarschall (Field Marshal) August von Mackensen. The ship was laid down on 30 January 1915 at Blohm & Voss in Hamburg, under construction number 240. She was launched on 21 April 1917; at the small launching ceremony, Generaloberst (Colonel General) Josias von Heeringen gave the speech and the ship was christened by Mackensen's wife. Construction was halted about 15 months before she would have been completed. The British mistakenly believed the ship to have been completed, and so they included the ship on the list of vessels to be interned at Scapa Flow instead of the fleet flagship . Mackensen was stricken from the German navy, according to the terms of the Treaty of Versailles, on 17 November 1919. She was sold for scrap and eventually broken up in 1922 at Kiel-Nordmole. Graf Spee was