| 3.7 cm/69 Flak M42[1] | |
|---|---|
 A single 3.7 cm Flak M42U gun on the LM 42U mount. | |
| Type | Anti-aircraft gun |
| Place of origin | Nazi Germany |
| Service history | |
| In service | 1943–1945 |
| Used by | Kriegsmarine |
| Wars | World War II |
| Production history | |
| Designed | 1942 |
| Manufacturer | Rheinmetall-Borsig |
| Produced | 1943–1945 |
| Specifications (3.7 cm Flak M42) | |
| Mass | 109 kg (240 lb) |
| Barrel length | 2.56 cm (1.01 in) bore (69calibers) |
| Crew | 3–4 |
| Shell | 37 × 249R |
| Shell weight | 635–700 g (1.400–1.543 lb) |
| Caliber | 37 mm (1.5 in) |
| Action | Recoil-operated |
| Breech | sliding breech block |
| Elevation | -10° to +90° |
| Traverse | 360° |
| Rate of fire | 250 rounds per minute (cyclic) |
| Muzzle velocity | 815–865 m/s (2,670–2,840 ft/s) |
| Effective firing range |
|
| Feed system | 5-round clips |
The3.7 cm Flak M42 was the marine version of the3.7-centimetre (1.5 in) Flak 36/37 and used by theKriegsmarine on surface ships and as theM42U onType VII andType IX U-boats. The 3.7 cm Flak M42U used several types of mounts and entered service in autumn 1943.[2]
The 3.7 cm Flak M42 was a longercaliber version of theWehrmacht's 3.7 cm Flak 36, 69 caliber as opposed to 57 caliber. It replaced the older3.7 cm SK C/30 that had been designed in 1930. The gun was loaded with a five-round ammunition clip, giving it a rate of fire of 250 rounds per minute, unlike the SK C/30 which was single-shot with a rate of 30 rounds per minute. The M42 was also about 134 kg (295 lb) lighter than the SK C/30 and had gun shields.[1][3]
The LM 42U mount was developed specifically for the 3.7 cm Flak M42U. It was manned by a 3-man crew, with a fourth man operating as the loader.[4]
The twin mount was based on the LM 42U design, in which the 3.7 cm Flak M42U guns were mounted side by side.[5]
The LM 43U mount was the final design of mount used on U-boats. It was a further improvement on the LM 42U. The LM 43U was only known to be installed on these U-boats (U-249,U-826,U-977,U-1023,U-1171,U-1305 andU-1306).[5]
