- A.N. Other and NHSA Webmaster
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- RAN Ships
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- June 1981 edition of the Naval Historical Review (all rights reserved)
WHEN NELSON FOUGHT THE BATTLE OF TRAFALGAR his ships, and those of the enemy, used guns that differed very little from those used by Drake to beat the Spanish Armada almost three hundred years before. Possibly the most important improvement that had appeared was the use of a lock to fire the charge, but to all intents and purposes the gun was still the old smooth bore muzzle loader firing round shot. Various types of projectiles were in use for specific purposes, such as chain shot and bar shot to smash rigging, and grapeshot to wipe out the guns crews of the enemy. The main obstacle was the lack of range with the smooth bore, and one way out was to fire an elongated shell. Using this type of projectile a shell weight of at least double could be realised. But the smooth bore didn’t go well with the elongated shell, accuracy fell off very quickly as the shell rolled end over end through the air. The rifled barrel solved this problem.
The problem of loading the long and heavy shell had to be overcome. On its simple truck carriage, the muzzle loading gun had to be run back inside the ship to be loaded, a lot of space was therefore required in front of the muzzle, and this of course was very difficult to obtain in a warship.
One way to tackle this problem was to load the gun through the breech, a system that had a lot to its credit. With this system there was no need to expose the loading numbers to enemy fire, as all the loading operations would be carried out at the rear, and for guns in exposed positions it would be a simple matter to provide a shield.
As to who actually invented the breech loading system, we now know it is open to debate as there are two distinct methods to follow up. One of the most common was the interrupted screw, in which a screwed plug was locked into the rear of the barrel. Sections of the screw threads were removed from both the breech plug and the barrel. It was then a simple matter to push the plug in and turn it, the threaded sections locking the two parts together.
The other method was to use a flat wedge to close the breech, a system that is in use today, although far removed from the original idea.
Development of the breech loading system ran along different lines throughout Europe, the French favouring the screw breech block, whilst the British muddled on with the wedge.
Mr. William Armstrong, later Sir W.G. Armstrong, brought out his breech loading gun and offered it for trials. First indications were that here was a truly reliable system. Results were to prove otherwise.
The screw was made hollow so that the shell and charge could be rammed home from the rear. The method of loading was simple. The screw was wound back, the vent was lifted out of the gun, the projectile and charge were then introduced through the screw. The vent was then replaced and the screw tightened up. This was where the main problems arose. To seal the escape of gases at the rear of the barrel, a copper ring was fitted into the vent piece, and the tension of the screw was supposed to effect a seal. Practice was to show that a gun could be fired with the screw not tight enough, and many nasty accidents occurred.
One of the main objections to the new gun was that it was in most cases less powerful than the old muzzle loaders, but with dogged British persistence the Board of Ordnance carried on, and many thousands of the new guns were produced, until finally they admitted to defeat. It was a simple matter of buying before trying.
The objections to this system are quite obvious when the drawings are examined. To fire a charge, a flame had to be transported down a right angled vent, drilled in this manner for two main reasons. The first one was that it was an easy matter to drill the two holes, the second and main reason being that it would have been virtually impossible to drill an angled hole that would strike the charge at the base, without weakening the vent piece itself.