BL 14 inch Mk VII naval gun

The BL 14 inch Mk VII naval gun was designed for the battleships of the Royal Navy in the late 1930s. This gun armed the battleships during the Second World War.

Background
The choice of calibre was limited by the Second London Naval Treaty, an extension of the Washington Naval Treaty which set limits on the size armament and number of battleships constructed by the major powers. After disappointing experiences with the combination of high velocity but relatively light shell in the BL 16 inch /45 naval gun of the s, the British reverted to the combination of lower velocities and (relatively) heavier shells in this weapon.

Design
These built-up guns were constructed using a non wire wound radial expansion design which was an advance on previous British practice with a longer barrel life and better accuracy. Unfortunately, the choice of mountings was for quadruple turrets, and in practice these developed a reputation as being unreliable with the turrets jamming during battle. However, it has been argued that these jams were typically caused by errors in drill, either due to lack of gun crew training, as was the case when the newly commissioned HMS Prince of Wales (53) engaged the GERMAN BATTLESHIP Bismarck in the Battle of the Denmark Strait (1941), or due to crew fatigue resulting from the prolonged nature of the engagement, as was the case when HMS King George V (41) engaged Bismarck in 1941, and HMS Duke of York (17) engaged GERMAN BATTLESHIP Scharnhorst in the Battle of North Cape (1943).

Coastal guns
Main article Cross-Channel guns in the Second World War. Two guns, nicknamed Winnie and Pooh, were also mounted in World War II as coastal artillery near Dover to engage German batteries across the Channel in occupied France.

Armour penetration

 * Penetration: belt 668 mm/0 m; 396 mm/9,144 m; 335 mm/13,716 m; 285 mm/22,860 m; decks 29 mm/9,144 m; 50 mm/13,716 m; 73 mm/18,288 m; 102 mm/22,860 m; 121 mm/25,603 m(4.74 in/28,000 yards)