Type 1936A destroyer

The Type 1936A destroyers, also known as the Z23 class, were a group of fifteen destroyers built for the Nazi Germany's Kriegsmarine from 1938 to 1943. They were known to the Allies as the Narvik class. In common with other German destroyers launched after the start of World War II, the Narviks were unnamed, known only by their hull numbers – Z23 to Z39.

Design
In terms of armament, they were closer to light cruisers than the typical destroyer. The use of 15 cm guns was atypical of destroyers which tended to have guns around 120 – in calibre. They were intended to carry two forward guns in a twin turret, but as the twin turrets were not ready in time, early class 1936As carried a single mounted gun forward.

Despite being powerful the ships were not without their flaws. There were problems with the reliability of the high pressure steam engines and seakeeping in rough seas due to the newly designed bow and heavy forward artillery.

The eight ships of the Type 1936A design (Z23 to Z30) were all laid down between 1938 and 1940. The seven destroyers numbered from Z31 to Z39 were classed as Zerstörer 1936A (Mob); they were laid down in 1940 and 1941 and were slightly larger and had some internal modifications (including engines that caused less trouble than with their predecessors) from the original design to shorten construction times.

Description
The ships had an overall length of 127 m and were 121.9 m long at the waterline. They had a beam of 12 m, and a maximum draught of 4.38 - 4.65 m. They displaced 2543 - 2657 LT at standard load and 3519 - 3691 LT at deep load. The ship's hulls were divided into 16 watertight compartments and they were fitted with a double bottom that covered 47% of their length amidships. Their crew consisted of 11–15 officers and 305–20 sailors; when serving as a flagship an additional 4 officers and 19 sailors were assigned.

The Type 1936As were powered by two Wagner geared steam turbine sets, each driving a single three-bladed 3.2 - 3.35 m propeller, using steam provided by six high-pressure Wagner water-tube boilers with superheaters that operated at a pressure of 70 atm and a temperature of 450 - 480 °C. The turbines were designed to produce 70000 PS for a speed of 36 kn. The ships carried a maximum of 835 t of fuel oil which gave a range of 2600 nmi at 19 kn.

Armament and sensors
The main armament of the Type 1936A ships was intended to be five 45-calibre 15 cm TbtsK C/36 guns in a twin-gun turret forward and the three other guns in single mounts with gun shields aft of the main superstructure, but delivery of the turrets was delayed and all of the Type 36A class was delivered with four single 15 cm guns with one gun forward and three aft. Z28 was the sole exception as its armament was arranged with two single mounts fore and aft. Z23, Z24, Z25 and Z29 were later fitted with the turret. All of the Type 36A (Mob) ships except Z31 were built with the turret and that ship received one later. The single mounts had a range of elevation from −10° to +30° while the guns in the turret could be elevated to 65°. The TbtsK C/36 gun fired 45.3 kg projectiles at a muzzle velocity of 835 m/s which gave them a maximum range of 21950 m. The hand-loaded gun had a maximum rate of fire of 7–8 rounds per minute and the ships carried a total of 480 shells for them.

Their anti-aircraft armament consisted of four 80-calibre 3.7 cm SK C/30 guns in two twin mounts abreast the aft funnel. The power operated mounts had a maximum elevation of 85° which gave the guns a ceiling of 6800 m; horizontal range was 8500 m at an elevation of 37.5°. The single-shot SK C/30 fired 0.748 kg projectiles at a muzzle velocity of 1000 m/s at a rate of 30 rounds per minute. The mounts were stabilized, but their gyroscopes were undersized and could not cope with sharp turns or heavy rolling. They were also fitted with five to ten fully automatic 65-calibre 2 cm C/30 guns in quadruple and single mounts. The gun had an effective rate of fire of about 120 rounds per minute. Its 0.134 kg projectiles were fired at a muzzle velocity of 835 m/s which gave it a ceiling of 3700 m and a maximum horizontal range of 4800 m.

The ships carried eight above-water 53.3 cm torpedo tubes in two power-operated mounts. Two reloads were provided for each mount. The standard torpedo for the Type 36B destroyers was the G7a torpedo. It had a 300 kg warhead and three speed range settings: 14,000 m at 30 kn; 8,000 m at 40 kn and 6,000 m at 44 kn. They had four depth charge launchers and mine rails could be fitted on the rear deck that had a maximum capacity of 60 mines. 'GHG' (Gruppenhorchgerät) passive hydrophones were fitted to detect submarines and a S-Gerät sonar was also probably fitted. The ships were equipped with a FuMO 24/25 radar set above the bridge.

Ships
The class, including the 36A (Mob), consisted of 15 ships. All were built in Bremen by AG Weser shipyard (part of Deutsche Schiff- und Maschinenbau AG/Deschimag) apart from Z37, Z38 and Z39 which were built by Germania (Kiel).