RML 12.5 inch 38 ton gun
Encyclopedia
The RML 12.5 inch guns were large rifled muzzle-loading guns designed for British battleships and were also employed for coast defence.
. Experiments in 1874 with both 12-inch and 12.5-inch versions 3 feet longer than the existing 12-inch gun showed the 12.5 inch calibre was more suitable, and further experiments showed a projectile of 800 pounds could be fired with a charge of 130 pounds of P2 gunpowder without undue strain. The same construction as in the existing 12-inch 35-ton gun was used : a mild steel "A" tube toughened in oil, surrounded by wrought iron
"B" tube, triple coil in front of the trunnion, coiled breech-piece and breech coil. This was approved in January 1875.
The gun was rifled on the "Woolwich" pattern of a small number of broad shallow rounded grooves, with 9 grooves increasing from 0 to 1 turn in 35 calibres ( i.e. 1 turn in 437.5 inches).
Mark II had an enlarged powder chamber and attained higher muzzle velocity and slightly longer range.
This gun was the final development of large British rifled muzzle-loading guns before it switched to breechloaders beginning in 1880. It was succeeded in its class on new battleships by the BL 12-inch Mk II gun
.
commissioned in 1879, HMS Agamemnon
commissioned in 1883, and HMS Ajax
commissioned in 1885, the last British warships completed with muzzle-loading guns.
Design
The gun originated from a desire for a longer 12-inch gun than the existing RML 12 inch 35 ton gunRML 12 inch 35 ton gun
RML 12 inch 35 ton guns were large rifled muzzle-loading guns used as primary armament on British battleships. They were the longer and more powerful of the two 12-inch British RML guns, the other being the 25-ton gun.-Design:...
. Experiments in 1874 with both 12-inch and 12.5-inch versions 3 feet longer than the existing 12-inch gun showed the 12.5 inch calibre was more suitable, and further experiments showed a projectile of 800 pounds could be fired with a charge of 130 pounds of P2 gunpowder without undue strain. The same construction as in the existing 12-inch 35-ton gun was used : a mild steel "A" tube toughened in oil, surrounded by wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
"B" tube, triple coil in front of the trunnion, coiled breech-piece and breech coil. This was approved in January 1875.
The gun was rifled on the "Woolwich" pattern of a small number of broad shallow rounded grooves, with 9 grooves increasing from 0 to 1 turn in 35 calibres ( i.e. 1 turn in 437.5 inches).
Mark II had an enlarged powder chamber and attained higher muzzle velocity and slightly longer range.
This gun was the final development of large British rifled muzzle-loading guns before it switched to breechloaders beginning in 1880. It was succeeded in its class on new battleships by the BL 12-inch Mk II gun
BL 12 inch naval gun Mk I - VII
The BL 12 inch naval gun Mk I was Britain's first attempt to match the large breech-loading naval guns being installed in rival European navies, particularly France...
.
Naval service
Guns were mounted on HMS DreadnoughtHMS Dreadnought (1875)
The fifth HMS Dreadnought of the British Royal Navy was a turret ironclad battleship built at Pembroke Dockyard, Wales.-Construction:Begun as Fury in 1870, the original design was recast for heavier armour and higher speed. The renamed ship was laid down in 1872 at Pembroke Dockyard and was...
commissioned in 1879, HMS Agamemnon
HMS Agamemnon (1879)
HMS Agamemnon was a Victorian Royal Navy Ajax class ironclad turret battleship, the sister-ship of .Agamemnon and Ajax were built to the same design, and were smaller and less expensive versions of Inflexible...
commissioned in 1883, and HMS Ajax
HMS Ajax (1880)
HMS Ajax was the first of the two Royal Navy Ajax class ironclad battleships to be laid down, but was completed one day later than her sister,...
commissioned in 1885, the last British warships completed with muzzle-loading guns.
Surviving examples
- At Hurst CastleHurst CastleHurst Castle on the south coast of England is one of Henry VIII's Device Forts, built at the end of a long shingle barrier beach at the west end of the Solent to guard the approaches to Southampton. Hurst Castle was sited at the narrow entrance to the Solent where the ebb and flow of the tides...
, UK - At Fort Nelson, PortsmouthFort Nelson, PortsmouthFort Nelson, in the civil parish of Boarhunt in the English county of Hampshire, is one of five defensive forts built on the summit of Portsdown Hill in the 1860s, overlooking the important naval base of Portsmouth. It is now part of the Royal Armouries, housing their collection of...
, UK - Outside Fort Albert, Isle of Wight
- No 22 of 1876 outside Calbourne Mill, Isle of Wight, originally at Cliff End Battery
- An unpreserved gun at Fort DelimaraFort DelimaraFort Delimara is a fortification in Marsaxlokk, Malta.-History:The fort was built between 1876 and 1888 by the British. The main gate carries a date of 1881, but this is the date of completion of the gatehouse, not the commissioning of the fort....
, Malta
External links
- Diagram of gun on small port 6 foot recoil carriage at Palmerston Forts Society website
- Diagram of gun on Casemate Platform, 6 feet recoil Mark III at Palmerston Forts Society website
- Diagram of gun on on Dwarf 'C' Pivot Mark III at Palmerston Forts Society website