The Blomefield Pattern Cannon

Once John Armstrong had finished his basic design for British artillery in 1725, there were only marginal changes to the template over the next 70 years.

That changed In 1780, when a 36 year old artillery captain was appointed as Inspector of Artillery and Superintendent of the Royal Brass Foundry.

Thomas Blomefield, son of the Rev. Thomas Blomefield, rector of Hartley and Chalk, Kent, and Chaplain to the Duke of Dorset, was born in 1744.

When he was 11 years old he was sent to sea on HMS Cambridge (80) under a close friend of his father, Sir Peircy Brett. His naval career was short lived and in February 1758 he enrolled as a cadet at the Royal Military Academy at Woolwich.

He was a talented student, gained the notice of his professors and passed out as a lieutenant eleven months later at age 15. He saw combat in the West Indies and Florida. He became aide de camp to General Conway, who was then acting Master General of the Ordnance and was retained in that position by his successor, Lord Townshend.

He resigned that high profile post to serve in the war in America. He was wounded in the head at Saratoga, returned to his duties as aide to the Master General of Ordnance. In 1780 he was appointed Inspector of Artillery and Superintendent of the Royal Brass Foundry.

At the time Britain’s military administration was virtually belly up. The nearly medieval system of military administration used by Britain was obviously incapable of supporting an army and navy engaged in a worldwide war.

Blomefield set about his task with energy. In his first year he condemned 496 new artillery pieces and unsuitable before they were sent to the army or the fleet. This represented about a quarter of the national production.

Around 1783, Blomefield set his hand to designing artillery. Apparently he was a dedicated experimenter and used his experiments to inform his designs. There are several key deviations from the Armstrong-Frederick pattern gun in the Blomefield gun.

First, it is much more simple in design. A lot of the more decorative features at the cascabel were done away with to ensure a uniform thickness of metal.

Second, an attempt was made to lessen the weight of the gun by trimming the thickness of the tube while retaining a strong breech. This is a theme one sees with cast iron guns probably culminating in the Parrot guns

Third, the chamber for the powder bag was a bit larger in diameter than the bore. This resulted in a better burn rate for the powder and hence a higher muzzle velocity.

Lastly, a loop was forged over the knob on the cascabel. Aboard ship, this enabled the breeching rope to pass through the loop rather than being looped around the knob. This subtle change enable shipboard artillery to be shifted much farther off the center line because it could be fired with the risk of snapping the breeching rope.

After 1794 the Blomefield pattern gun was the standard within the navy.

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2 Comments

Filed under Age of Sail, Naval Equipment, Naval Gunnery, Naval Weapons

2 responses to “The Blomefield Pattern Cannon

  1. Graeme

    Um.
    Generally correct, but Blomefield guns had the bore parallel full length. Carronade had a chamber one calibre smaller than the bore – eg, an 18 pdr carronade had its chamber bored equal to a 12 pdr. This was partly to reduce weight.
    A chamber larger than the bore cannot work with a muzzle loader, as the cartridge will either be loose, or be burst when ramming. As for what might happen if, say, a round of grape got its base foul of the step…
    Question. Anyone know whether Blomefield redesigned the Armstrong 1/2 pdr swivel?

  2. Pingback: Τα κανόνια του δικέφαλου αετού των Ρωμανώφ στην Κέρκυρα

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