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BL 8-inch MkVIII Naval Gun

There were only six 8-inch gun deployed in the coast defence role during the 20th Century but they had an important part to play in the defences along the English Channel narrows after 1942. The guns involved were Mark 8 naval guns acquired by the Army in 1940 at a time when long range coast defence guns were in great demand. Originally intended as the main armament of County class cruisers, the guns were adopted complete with their naval mountings which meant they could have a dual purpose role by also acting as heavy anti-aircraft guns as their maximum elevation was +70°. All barrel and mounting movements were powered, as were the breech mechanism operations.

The guns were installed at two locations, Capel near Folkestone and Hougham, west of Dover. Both batteries were ready by 1942, their single-gun turret installations involving a frontal mounting pivot and a traversing arc to gain an optimum arc of fire. The two batteries operated under a single radar fire control that enabled the guns to successfully engage enemy shipping targets at extreme ranges of up to 28,030 m.

The two 8-inch batteries were stood down during 1952.
  
BL 8-inch MKVIII Gun data
Calibre 203.2 mm
Projectile weight 116 kg
Length of barrel 10,493 mm
Length of bore 10,160 mm (L/50)
Length of rifling 8,796 mm
Weight of gun 17,527 kg
​Elevation -7 to +70°
Traverse 160°
Muzzle velocity 855 m/s
Max range ca 28,030 m