The British RML 8-inch 9-ton guns Mark I – Mark III[5] were medium rifled muzzle-loading guns used to arm smaller ironclad warships and coast defence batteries in the later 19th century.
| RML 8-inch 9-ton gun | |
|---|---|
 Gundeck of HMS Northumberland | |
| Type | Naval gun Coast defence gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1866–190? |
| Used by | Royal Navy |
| Production history | |
| Manufacturer | Royal Arsenal |
| Unit cost | £568[1] |
| Variants | Mk I – Mk III |
| Specifications | |
| Mass | 9 long tons (9.1 t) |
| Barrel length | 118 inches (3.0 m) bore + chamber[2] |
| Shell | 174 pounds 12 ounces (79.3 kg)[3] |
| Calibre | 8-inch (203.2 mm) |
| Muzzle velocity | 1,420 feet per second (430 m/s)[4] |
Design edit
In common with other Royal Ordnance RML designs of the 1860s, Mark I used the strong but expensive Armstrong system of a steel tube surrounded by a complex system of multiple wrought-iron coils, which was progressively simplified in Marks II and III to reduce costs : Mark III consisted only of A tube, B tube, breech coil and cascabel screw.
Rifling was of the "Woolwich" pattern of a small number of broad shallow grooves: 4 grooves with twist increasing from 0 to 1 turn in 40 calibres (i.e. in 320 in (810 cm)) at the muzzle.
Ammunition edit
The ammunition was mainly studded, with the studs engaging in the Woolwich rifling grooves. However, a studless pointed common shell with automatic gas-check also became available later in the gun's life.[6]
See also edit
Surviving examples edit
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Notes and references edit
- ^ Unit cost of £567 12 shillings 10 pence is quoted in "The British Navy" Volume II, 1882, by Sir Thomas Brassey. Page 38
- ^ Text Book of Gunnery 1887 Table XVI page 313
- ^ 174 lb 12 oz projectile. Text Book of Gunnery 1887 Table XVI page 313
- ^ 1,420 feet/second firing 174-pound 12-oz projectile . Text Book of Gunnery 1887 Table XVI page 313
- ^ Mark I – Mark III = Mark 1 through to Mark 3. Britain used Roman numerals to denote Marks (models) of ordnance until after World War II. Hence this article describes the three models of RML 8-inch guns.
- ^ Gas-checks in British RML heavy guns
Bibliography edit
External links edit
