Following the recent find after the winter storms this posting will perhaps provide some historical information about navel cannon
With thanks to
The Smooth Bore Cannon
For centuries naval warfare at sea consisted of sailors boarding enemy ships and fighting hand to hand. The early naval guns were anti-personnel weapons, mounted on the stern and forecastle that discharged all manner of shot.
It wasn’t really until the 16th Century that the English Tudor Navy adapted French culverins for use at sea, These were fairly light guns with long barrels, and fired round shot. The Mary Rose was the first purpose built English warship with a mixture of brass and iron ordnance, and the first ship to fire a broadside.
The word “cannon” is believed to be derived from the word cane, tube or reed in several different languages. It actually refers to a size of gun and was the next in size to the largest “Cannon Royal”, a 12 foot gun capable of firing 48 pound shot. Before standardization in the 18th Century there was an enormous range of calibres and lengths of guns.
“Guns” are “ordnance”, and there is “brass ordnance” (actually bronze), and “iron ordnance”, both used on land and at sea.
“Muzzle-loading” guns are loaded from the front, with everything rammed down the barrel. “Breech-loading” guns are loaded from the rear. The earliest wrought-iron guns were breech-loaders, but these fell into disuse by the late 16th century. Breech-loaders were re-introduced in the late 19th century, and went on to become the standard method for sea and land based guns.
A description of the parts of a cannon
The Cascabel originally referred to the round knob at the breech end of the gun, but later came to represent the entire area behind the Base (or Breech) Ring, the round knob known as the Button. Iron guns incorporated a Cascabel Loop in the neck of the Cascabel (see the George III gun).
The breech (or breech chamber) is the area within the vent field where the powder is ignited. Gun length is measured from the muzzle to the rear end of the Base/Breech Ring. The Vent (or Touch-Hole) is a hole at right angles to the breech through which the gunpowder is poured and ignited to set off the charge and to fire the gun.
The first part of the gun barrel from the Base/Breech ring to the trunnions is called the First Reinforce. This is this thickest part of the gun, necessarily to withstand the pressure generated by the exploding charge in the breech. The Second Reinforce is the next tapered section of the barrel and is where the Trunnions are fitted. On bronze cannon, lifting handles were also fitted here, often elaborately ornamented as dolphins or similar.
The final section of the barrel, ending in the muzzle and face of the gun.
The junctions of the Reinforces and the Chase are marked by wide flat rings (Reinforce Rings), which sometimes have adjacent Ogees and Fillets. Astragals are another type of moulded ring which has a semicircular section.
The muzzle is the section at the open end of the Chase. The narrowest part of the barrel, the muzzle neck flares out to the swell before narrowing again to the muzzle face of the gun. At this point there may be muzzle mouldings – Astragals, Ogees or Fillets.
Trunnions are cylindrical projections from either side of the barrel, just forward of the centre of gravity, that enabled the gun to pivot up and down in its carriage.
The vertical position of trunnions relative to the bore, however was subject to change, and some debate. When they were first conceived in about 1450 they were quite logically positioned with their horizontal axis coincident with the vertical centre of the bore. Because at that time there was no elevating mechanism to hold the gun in place, it tended to rock up and down when fired. To prevent this, it was calculated that the trunnion should be moved so that it was aligned with the bottom of the bore, in so doing the forces generated upon firing would hold the breech down. This worked, but often resulted in the wedged shaped quoin used for achieving elevation, being ejected backwards. The trunnions remained in this position right up until the middle of the 18th Century when the Board of Ordnance were finally convinced that the best position where they were originally, and moved them.
Early gun design was largely based upon the rules of proportion with the various dimensions expressed in units of the calibre, the diameter of the round shot the gun fired. For example, trunnions were made the same diameter as the calibre, and were placed at 4/7ths of the length from the muzzle. The walls of the barrel were one calibre thick at the breech, and a half calibre at the chase. The circumference at the breech was 9 calibres, 7 calibres at the trunnions, and 5 calibres at the muzzle. There do not appear to be any logical reasons these dimensions, for the designers had no means of gauging bore pressures, muzzle velocity, or strength of materials.
At the beginning of the 18th Century, armies and navies started standardizing the dimensions and calibres of their artillery. Sometime after the succession of George I to the English Throne in 1714. the Board of Ordnance set out to rationalise the Royal Ordnance, and appointed Albert Borgardto develop a uniform pattern of cannon of varying sizes, including their carriages and shot.
Borgard was born In Holbech, Holland, and fought in the Danish, Polish and Prussion armies, before becoming Chief Fire Master at Arsenal, Woolwich in 1712. He was the first and last person to design a complete system of artillery. Fundamental to his designs, he dispensed with the naming of cannon as Culverin, Minion, Saker etc. and the guns became known by the weight of their round shot, with weights of approximately 4lb, 6lb, 9lb, 12lb, 18lb, 24lb, 32lb, and 42lb. The designs were accepted by the Board of Ordnance in 1716, and although later redesigned when John Armstrong took over as official designer in 1722, Bogard’s standards for the size of the cannonballs were to remain firmly established for their future use.
After Borgard’s departure, John Armstrong succeeded to the position of Surveyor General of Ordnance, and he was to control the develpoment of British ordnance for the next twenty years. By 1725 he had completely redesigned Borgard’s artillery systems with a complex serious of proportions for every section of the gun. The early craftmanship and elaborate decoration was dispensed with in favour of cast iron barrels that could be readily cast by any foundry.
In 1741, the Royal Military Academy was founded at Woolwich to train artillery and engineering officers.
The next major changes were to come in 1780 when a 36 year old artillery captain, Thomas Blomefield, was appointed as Inspector of Artillery and Superintendent of the Royal Brass Foundry. His first act was to condemn 496 pieces of new artillery as being unsuitable for delivery. Three years later he was entrusted with the complete reorganisatiion of the Ornance Department, and at the same time, embarked on experiments that enabled a new system of ordnance to be designed.His system, based on the calibre of the weapon, specified the length, wall thickness and other dimensions of the muzzle-loader gun. They were designed to use newly the improved "cylinder powder" developed by which apparently increased chamber pressures, bursting "old pattern" guns during testing.
The new Blomefield guns had the characteristic cascabel ring, thicker breeches and thinner chases. This gave a stronger gun without an increase in weight. Decorative elements were removed from the Blomefield pattern ordnance.
Although the Royal Navy also carried out their own experiments, and trialled variations on the Blomefield design against designs by Colonel Congreve (the inventor of rocket artillery), they ultimately adopted Blomefield’s designs and by 1794 the Blomefield pattern gun was the standard in the navy, although Armstrong’s were still on ships in 1808.
A typical firing procedure
A wet swab was used to mop out the interior of the barrel, extinguishing any embers from a previous firing. Gunpowder, either loose or in a cloth or parchment cartridge pierced by a metal 'pricker' through the touch hole, was placed in the barrel and followed by a cloth wad, was rammed home. Next the shot was rammed in, followed by another wad (to prevent the cannonball from rolling out of the barrel if the muzzle was depressed.) The gun in its carriage was then 'run out' — men heaved on the gun tackles until the front of the gun carriage was hard up against the ship's bulwark, and the barrel protruding out of the gun port. This took the majority of the manpower as the total weight of a large cannon in its carriage could reach over two tons, and the ship would probably be rolling.
The touchhole in the rear ('breech') of the cannon was primed with finer gunpowder ('priming powder'), or a 'quill' (from a porcupine or such, or the skin-end of a feather) pre-filled with priming powder, then ignited.
The earlier method of firing a cannon was to apply a linstock - a wooden staff holding a length of smoldering match at the end - to the touchhole of the gun. This was dangerous and made accurate shooting from a moving ship difficult, as the gun had to be fired from the side, to avoid its recoil, and there was a noticeable delay between the application of the linstock and the gun firing In 1745, the British began using flintlocks fitted to cannon).
The gunlock was operated by pulling a cord, or lanyard. The gun-captain could stand behind the gun, safely beyond its range of recoil, and sight along the barrel, firing when the roll of the ship lined the gun up with the enemy and so avoid the chance of the shot hitting the sea or flying high over the enemy's deck. Despite their advantages, gunlocks spread gradually as they could not be retrofitted to older guns. The British adopted them faster than the French, who had still not generally adopted them by the time of the Battle of Trafalgar (1805)
Evolution of the British Gun in by Clive Sweetingham
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