BL 13.5 inch naval gun Mk I – IV

The BL 13.5 inch naval gun Mk I ("67-ton gun") was Britain's first successful large breechloading naval gun. Mks I - IV were all of 30 calibres length and of similar construction and performance.

Royal Navy service
The gun was designed to match the new large guns of the French battleships. Development and manufacture occurred very slowly. It was originally intended to equip the s, begun in 1880, but delays led to HMS Collingwood (1882) being equipped with inferior 12 inch guns and HMS Benbow (1885) with the subsequently unsuccessful 16.25 inch guns.

The remaining Admiral-class ships, HMS Anson (1886), HMS Camperdown (1885), HMS Howe (1885) and HMS Rodney (1884), were eventually completed in 1889 equipped with four 13.5 inch guns each, in twin barbettes on the centreline at each end of the superstructure.

The guns also equipped the subsequent laid down in 1886 and s laid down in 1889.

Coast defence service
A single Mk III gun was mounted as a disappearing gun for coast defence at Penlee Battery, Plymouth.

Italian service
Guns were also sold to Italy to arm the s ITALIAN BATTLESHIP Re Umberto, ITALIAN BATTLESHIP Sicilia, and ITALIAN BATTLESHIP Sardegna, laid down in 1884 and finally commissioned in 1893 and 1895. 

Weapons of comparable role, performance and era

 * 340mm/28 Modèle 1881 gun French equivalent