The Siege platform was a portable platform used to mount a siege gun or mortar, or a field piece when it was needed to fire from the same place for any length of time. It was easily transported to a field battery where it could be used to support the defence of a fortress by supplementing the fire of the forts.
The siege platform generally consisted of a layer (or two layers) of planks supported by sleepers. Patterns in use were Alderson's and Clerk's platforms. Some were double decked to support heavier field pieces.
The Volunteers often practised using 64pr RML guns mounted on garrision carriages and a siege platform was ideal to mount such pieces in Volunteer practise batteries.
At fort Nelson the PFS has constructed a siege platform on the west rampart of the fort to supplement the range of weapons fired by the PAV during dispaly firings for the public. The barrel and cariage are originals provided by the Royal Armouries.
A 64pr RML studded shell
The 64pr. R.M.L. 58cwt mounted on a Garrison Standing Carriage and double decked siege platform, on the West Rampart at Fort Nelson.
The 64pr. R.M.L.
The 64 pr. gun was the first muzzle-loading rifled piece introduced into the service. It was the heavy gun of its day and superseded the B.L. wedge gun of about the same weight. The adoption of the muzzle loading guns was decided upon in 1864 after years of experiment and trial and the calibre of 6.3-inches was chosen so that these guns might be able to fire 32pr. spherical shot. Some 64pr. guns in the service were conversions from 32pr. Smooth Bore guns and 8-inch shell guns on the Palliser principle. Later a 64pr. of 64cwt. built up gun was introduced, which passed through three changes of pattern the Mark III having a steel barrel. The manufacture of the Mark III was commenced in 1867 after it was proved that this system of construction was stronger than that in which a forged breech was used.
Common Wood Carriage
The carriage on which the 64pr RML stands is a common wood carriage, a conversion from the 8-inch naval carriage. It consists of two brackets of elm, a transom of elm, two axletrees of oak and four trucks. The standing garrison carriage was usually only employed for positions flanking the ditch of a fort or for embrasures in barrack rooms. perhaps at the gorge, or rear of a fort. They were not to be used on the front faces of a fort. It required a ground platform of wood, stone or concrete 18ft. by 12 feet. with a slope of 1/24. The gun fired over a sill two feet three inches high. By the late 1880s 64 prs, were mounted on rear chock carriages rather than garrison standing carriages because of their recoil.
Three types of ammunition were employed by this nature of gun. Case shot was for use against troops in masses, for flanking ditches with an effective range of not much more than 350 yards. Shrapnel was for use against troops in the open at distances beyond case shot range. Common shells were for use against troops behind cover, against wooden ships or buildings.
The 64pr fired a common shell which weighed 57lbs 6oz when empty. It had a bursting charge of 7lbs 2 oz.
It also fired a shrapnel shell, which when filled with 234 mixed metal balls (14 to the pound) weighed 66 lbs 90z and a bursting charge of 90z.
Case shot, weighed 49lb 14.5oz when filled with eight-ounce sand shot packed in clay and sand.
A full charge for the Mark III was 10lbs of powder. The cartridge bags were of white serge but later replaced with silk.
A detachment of 9 gun numbers is usually employed for the 64pr. on a standing carriage.
No.1 commands, directs or superintends boring and fixing fuzes, directs the gun into the line of fire in running up, and lays.
No.2 searches, sponges, rams home, runs up elevates and traverses.
No.3 loads, uncaps or removes safety pin from fuze when in the bore, rams home, runs up elevates and traverses.
No.4 attends to side arms a supplies them to 2 runs up and attends to the elevating screw and coin in laying.
No.5 attends to the vent, runs up, makes ready and fires.
No.6 supplies 3 with cartridges.
No.7 attends to fuzes and brings up projectiles.
No.8 attends to cartridge store and serves out a cartridge to 6.
No.9 attends to shell store, issues shells, tubes and fuzes.
The 64pr R.M.L. at Fort Nelson
The Portsdown Artillery Volunteers performing a practice drill on a 64pr R.M.L. at Pendennis Castle