The RML 10-inch guns Mk I – Mk II were large muzzle-loading rifle, rifled muzzle-loading guns designed for British battleships and monitor (ship), monitors in the 1860s to 1880s. They were also fitted to the
and flat-iron gunboats. They were also used for fixed coastal defences around the United Kingdom and around the British Empire until the early years of the 20th century.
Design
The gun was a standard "Royal Arsenal, Woolwich" design (characterised by having a steel A tube with relatively few broad, rounded and shallow rifling grooves) developed in 1868, based on the successful RML 9-inch 12-ton gun, Mk III gun, itself based on the "Fraser" system. The Fraser system was an economy measure applied to the successful William George Armstrong, 1st Baron Armstrong, Armstrong design for heavy muzzle-loaders, which were expensive to produce. It retained the Armstrong steel barrel surrounded by wrought-iron coils under tension, but replaced the multiple thin wrought-iron coils shrunk around it by a single larger coil ( Mark I) or 2 coils (Mark II); the trunnion ring was now welded to other coils; and it eliminated Armstrong's expensive forged breech-piece.
The gun was rifled with 7 grooves, increasing from 1 turn in 100 calibres to 1 in 40.
It was first used for the main armament on the central battery ironclad , completed in late 1868.
A number of the Mk I guns on HMS ''Hercules'' and one of the two damaged guns in HMVS ''Cerberus'' suffered from cracked barrels.
HMVS Cerberus website. reports of cracked guns
/ref> Presumably this is why only a few (at least 25) Mk I guns were made.
Ammunition
When the gun was first introduced projectiles had several rows of "studs" which engaged with the gun's rifling to impart spin. Sometime after 1878, "Gas-checks in British RML heavy guns#Attached Gas-Checks, attached gas-checks" were fitted to the bases of the studded shells, reducing wear on the guns and improving their range and accuracy. Subsequently, "Gas-checks in British RML heavy guns#Automatic Gas-Checks, automatic gas-checks" were developed which could rotate shells, allowing the deployment of a new range of studless ammunition. Thus, any particular gun potentially operated with a mix of studded and studless ammunition.
The gun's primary projectile was Palliser shot, "Palliser" shot or shell, an early armour-piercing projectile for attacking armoured warships. A large "battering charge" of "P" (pebble) or "R.L.G." (rifle large grain) British ordnance terms#Gunpowder, gunpowder[Treatise on Ammunition 1877, page 220] was used for the Palliser projectile to achieve maximum velocity and hence penetrating capability.
British ordnance terms#Common shell, Common (i.e. ordinary explosive) shells and shrapnel shells were fired with the standard "full service charge" of "P" or R.L.G. gunpowder,
Surviving examples
* 4 guns submerged near the remains of HMVS Cerberus, HMVS ''Cerberus'' in Half Moon Bay, Victoria, Australia (3 x Mk I & 1 x Mk II)
Damaged Mk I gun No. 17
from HMVS ''Cerberus'' is on display at HMAS Cerberus (naval base), HMAS ''Cerberus'' Victoria, Australia
Mark II gun No.35
at Parson's Lodge Battery, Gibraltar
Mark II gun no.38 at
York Redoubt, Halifax, Canada
* :File:Gibraltar, Southport Gates, Kanone.JPG, Mark II gun No. 67 at Southport Gates, Gibraltar
* commons:File:RML 10-inch guns Fort St Catherine.jpg, Mk II guns Mark II guns numbers 156, 180 (dated 1871), 195, 221 and 224 at Fort St. Catherine, St George's Island, Bermuda (Guns were originally from Fort Albert)
Mark II No. 273
at Gibraltar Botanic Gardens, Almeda Gardens, Gibraltar
Mark II guns, numbers 338, 340, 342, 356 and 357, dated 1878
Fort Cunningham, Paget Island, Bermuda
A Mark II at the Citadel, Quebec City, Canada
* A single gun at Chapel Bay Fort, United Kingdom
One Mk I Common Shell, one Mk II Common Shell & one Mk III Palliser Shot as part of the Victorian Navy display at the ''Geelong Maritime Museum'', Australia
Details
Various other guns are mounted or unmounted in Bermuda, with some lying outside of Fort St Catherine, having been rolled out when made obsolete (the guns actually mounted on display there were taken from other forts, notably Fort Albert), and a number having been found buried in the moat of Fort Cunningham (the two mounted at Fort George are the RML 11-inch 25-ton gun, RML 25-ton gun). Three have been erected on concrete display stands at Fort Hamilton, though the original mounts are missing, and another at Alexandria Battery.
See also
* List of naval guns
Notes and references
Bibliography
Treatise on the construction and manufacture of ordnance in the British service. War Office, UK, 1877
Treatise on Ammunition. 2nd Edition 1877. War Office, UK.
Manual for Victorian naval forces 1887. HMVS Cerberus website
Treatise on Ammunition, 4th Edition 1887. War Office, UK.
* Thomas Brassey, 1st Earl Brassey, Sir Thomas Brassey
The British Navy, Volume II. London: Longmans, Green and Co. 1882
Handbook for the 10-inch rifled muzzle-loading gun of 18 tons, 1899
at State Library of Victoria
"Handbook for the 10-inch R.M.L. Guns (Land Service)", 1903, London. Published by His Majesty's Stationery Office
at State Library of Victoria
External links
* [http://www.victorianforts.co.uk/art/10rml2.htm Diagram of gun on Dwarf "D" Pivot mounting, at Victorian Forts website]
Diagram of gun on 7-foot Parapet "C" mounting, at Victorian Forts website
{{VictorianEraBritishNavalWeapons
Naval guns of the United Kingdom
254 mm artillery
Victorian-era weapons of the United Kingdom
Coastal artillery