QF 4.7-inch ship gun Mk XI
| QF 4.7 inch Mk XI | |
 The front turrets of the MS Matchless |
|
| Caliber: | 120 mm (4.7 inch) |
| Barrel length: | 6.0 m (caliber length 50) |
| Weight: | 3405 kg (without ammunition) |
| Ammunition supply: | 150 SAP + 1000 HE + 50 flares per gun |
| Grenade weight: | separate projectile and propellant charge |
| Bullet weight: | 28.12 kg (HE) 28.12 kg (SAP) |
| Muzzle velocity: | 774 m / s |
| Elevation range: | Minimum –10 ° Maximum + 50 ° (Carriage Mk XX) |
| Range: | Effective: 10,500 m Max.19,420 m |
| Turning speed: | 10 ° / s |
| Increase speed: | only manually |
| Rate of fire: | 6-10 rounds / min |
| drive | Hydraulic motor for rotary movement |
The QF 4.7 inch (120 mm) was a British naval gun . The caliber length is 50 (6.0 m). The specified caliber of 4.7 inches corresponds to 119.4 mm, as with all British guns of this caliber the exact value is 4.724 inches (120 mm). Due to the high weight (approx. 48 kg) of the ammunition, the load and projectile were loaded separately.
development
In 1938, the Admiralty realized that the Royal Navy destroyers were clearly inferior to their US and Japanese counterparts. On the one hand, they did not have any heavy armament that would suffice for the dual role of combating sea and air targets, and on the other hand, the gun emplacements on board were not weatherproof. The 4.7 "/ 50 Mk-XI (12 cm) gun, together with the Mk XX double mount, was intended to correct these deficits. These guns fired a more modern and heavier shell than most British guns of this caliber and the mount allowed an extended range of elevation The low turning speed of 10 ° / s and the manually operated elevation unit limited the use against aircraft so much that in many of these destroyers during the Second World War the rear torpedo launcher was replaced by a single 4 "/ 45 Mk V (10.2 cm ) was replaced.
Construction
For cost reasons, the turrets were designed so that only the gun house turned, but not the ammunition lifts. This meant that the elevators for grenades and propellant had to be installed as part of the ship's structure in the axis of rotation. As a result, the guns were mounted unusually far apart. The construction had the advantage that the height adjustment of the individual cannons could be carried out independently of one another, but the permanently mounted elevators caused problems with ammunition replenishment as soon as the turret made major rotary movements.
The drive for the rotary movement, the loading process and the elevators was hydraulic. The entire turret construction was so complicated that there were long production delays and in the end four of the L-class destroyers were equipped with 4 "Mark XIX twin turrets instead of the 4.7" armament. Due to the high cost factor, the Royal Navy then returned to the cheaper 4.7 "/ 45 Mark IX guns for the new builds .
In total, only 87 Mk.-XI guns were made.
use
units
- Destroyer classes L and M
Web links
- Page from Navweapons about Mk XI (English)