BL 7.5-inch naval howitzer explained

BL 7.5-inch naval howitzer
Origin:United Kingdom
Type:Anti-submarine mortar
Is Artillery:yes
Is Ranged:yes
Is Explosive:yes
Is Uk:yes
Service:1917 - 192?
Used By:British Empire
Wars:World War I
Weight:Gun & breech 812lb[1]
Part Length:Bore 63.75inches
Cartridge:HE 100lb
Caliber:7.5sigfig=3NaNsigfig=3
Velocity:480ft/s
Max Range:2100yd
Breech:single-motion interrupted screw
Filling:TNT
Filling Weight:43lb[2]

The BL 7.5-inch howitzer (naval) was a British anti-submarine mortar developed during World War I.

History

The weapon was developed together with other similar devices early in 1917 and went into service in June 1917 in response to German unrestricted submarine warfare. It was mounted on merchant ships and patrol vessels. By 10 December that year, 377 were in service.

The shell was fired at the submarine either on the surface or submerged - hence it had attributes of both armour-piercing shell and depth charge. It was designed to first penetrate the submarine's outer hull without breaking up, and then detonate against the inner hull after a 2-second delay,[1] destroying the submarine. However the small weight of the shell limited its effectiveness, and the anti-submarine mortar did not become a truly successful weapon until the advent of the multiple-projectile Hedgehog during World War II.

Nonetheless Admiral John Jellicoe, writing a few years after the gun had gone into service, commented: "This weapon, although not very popular at first, soon, however, proved its value, when employed both from patrol craft and from merchant ships."[3]

Two were mounted on HMS Vindictive and used to bombard German defences during her participation in the Zeebrugge raid of 23 April 1918.

Similar weapons

Bibliography

Notes and References

  1. Hogg and Thurston 1972, Pages 148-149
  2. Standard shell was 100 lb, containing 43 lb TNT. In early 1918 a 500 lb stick bomb containing 250 lb TNT was developed, with a range of 300 yards. Hogg & Thurston 1972, page 148
  3. Jellicoe, 1920. Chapter III