Type 40 torpedo boat

The Type 1940 torpedo boats were a group of 24 torpedo boats that were intended to be built for Germany's Kriegsmarine during World War II. Although classed as fleet torpedo boats (Flottentorpedoboot) by the Germans, they were comparable to contemporary large destroyers. They were designed around surplus Dutch propulsion machinery available after the Germans conquered the Netherlands in May 1940 and were to be built in Dutch shipyards. Hampered by uncooperative Dutch workers and material shortages, none of the ships were completed before the Allies invaded Normandy (Operation Neptune) in June 1944. The Germans towed the three ships that were most complete to Germany to be finished, but one was sunk en route by Allied fighter-bombers and no further work was done of the pair that did arrive successfully. The remaining ships in the Netherlands were later broken up for scrap and the two that reached Germany were scuttled in 1946.

Background and design
When the Germans invaded the Netherlands on 10 May 1940, the Dutch were building four Gerard Callenburgh-class destroyers. HNLMS Isaac Sweers (1940) was towed to Britain before the Germans could reach the shipyard, the Germans finished Gerard Callenburgh as GERMAN DESTROYER ZH1 and neither Philips van Almonde nor Tjerk Hiddes could be finished and had to be broken up. Neither ship had had their propulsion machinery installed before the invasion and the Kriegsmarine decided to design a ship using them and taking advantage of surplus capacity in Dutch shipyards and factories. Although called torpedo boats by the Kriegsmarine, the Type 40 design was larger than any previous German torpedo boat design and were effectively destroyers.

The ships had an overall length of 114.5 m and were 110 m long at the waterline. They had a beam of 11.3 m, and a maximum draft of 3.81 m at deep load. The Type 40s displaced 1931 LT at standard load and 2566 LT at deep load. Their hulls were divided into 13 watertight compartments and they were fitted with a double bottom that covered 90% of their length. Their crew numbered 231 officers and sailors.

The Type 40-class ships had two sets of license-built Parsons geared steam turbines, each driving a single three-bladed 3.15 m propeller, using steam provided by three license-built Yarrow boilers that operated at a pressure of 28 kg/cm2 and a temperature of 380 °C. The turbines were designed to produce a maximum of 49500 shp for a speed of 35 kn. The ships carried a maximum of 561 t of fuel oil which gave a range of 2350 nmi at 19 kn.

Armament and sensors
The main armament of the Type 40 class consisted four 42-caliber 12.7 cm SK C/34 guns in single mounts with gun shields, two each superimposed, fore and aft of the superstructure, designated one to four from front to rear. Each mount had a range of elevation from -10° to +30° and the gun fired 28 kg projectiles at a muzzle velocity of 830 m/s. It had a range of 17400 m at maximum elevation. Each gun was provided with 150 rounds. The Type 40s were equipped with a 3 m rangefinder for the gunnery director atop the bridge and a 4 m rangefinder was mounted just forward of No. 3 gun.

Anti-aircraft defense was provided by a pair of twin 80-caliber 3.7 cm SK C/30 anti-aircraft (AA) gun mounts that were positioned on a platform abaft the funnel. The power-operated mount had a maximum elevation of 85° which gave the gun a ceiling of less than 6800 m; horizontal range was 8500 m at an elevation of 35.7°. 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 ships were also fitted with sixteen 2 cm C/38 guns in four quadruple mounts, two on a platform between the torpedo tube mounts and a pair on the upper bridge wings. The gun had an effective rate of fire of about 120 rounds per minute. Its 0.12 kg projectiles were fired at a muzzle velocity of 875 m/s which gave it a ceiling of 3700 m and a maximum horizontal range of 4800 m. Each ship carried 2,000 rounds per gun.

The Type 40s were also equipped with eight above-water 533 mm torpedo tubes in two quadruple mounts amidships. They used the G7a torpedo which 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. The ships could carry 50 mines. For anti-submarine work they were fitted with four depth charge launchers and six individual cradles for 32 depth charges.

Construction
The Kriegsmarine ordered T61–T68 on 19 November 1940, although T65–T68 were only provisional orders that were finalized on 6 January 1941. A batch of four more, T69–T72, were ordered on 3 May and the final batch of twelve, T73–T84, on 27 August. The contracts for T67, T68 and T72 were transferred from Nederlandsche Scheepsbouw Maatschappij to other builders in September 1943 before construction began. The Kriegsmarine originally estimated that the first six ships would be assigned to the 3rd Destroyer Flotilla which was expected to be formed in early 1943. The destroyers probably had a lower priority for labor and materials than the large numbers of minesweepers being built in Dutch shipyards, so that the first ships were not laid down until 1942. The Dutch workers hampered construction at every turn, but shortages of brass, copper and aluminum were such that construction of all ships except for two was suspended by April 1942, even though steel and machinery for the first dozen had either been assembled or was in production. Supposedly eight ships had been begun by the end of the year; by mid-1944 the Kriegsmarine was expecting only four ships to be finished before the end of the year, another four in 1945 and the last four in 1946, the last dozen ships having been cancelled earlier.

T65 was the first of three Type 40s that the Kriegsmarine had towed to Germany for completion. She departed Vlissingen on 8 September 1944 and arrived at Borkum, a week later. The ship was in Bremen in October and was then towed to Elbing, East Prussia, in late December to be finished at the Schichau shipyard. After the yard was shut down on 22 January 1945 due to power failures, a lack of workers and the advancing Soviet forces which were approaching East Prussia, T65 was towed that day to Danzig and then back to Bremen. The incomplete ship was scuttled on 2 July 1946 after being loaded with chemical weapons. T61 was the next to leave, departing Schiedam on 12 September. Her convoy was attacked by Bristol Beaufighter fighter-bombers from 455 Squadron RAAF that same day and she was sunk off Den Helder. T63 was towed from Rotterdam in November 1944 and arrived in Emden on the 29th and the Schillig Roads on 21 December. She was towed to Elbing for further work, but was towed back to Kiel in January 1945. Much like T65, the ship was loaded with chemical munitions before she was scuttled in the Skaggerak on 31 December 1946.