The Evolution of Naval Armament

by Frederick Leslie Robertson

From Binning’s A Light to the Art of Gunnery, A.D. 1689

The first guns had no trunnions. To obtain the requisite angle of elevation the piece was laid in a dug-out trunk or carriage and this carriage was set on trestles; in which manner, it appears, the English at the siege of Orleans in A.D. 1428 “threw into the town from their bombards large numbers of stones which, flying over the walls, smashed in the roofs of houses.”[65] During the fifteenth century trunnions came into use, and the carriages were mounted on wheels. In his Introduction of Artillery into Switzerland a French writer, Colonel Massé, has given an account of the early evolution of an artillery of position, as used by the Swiss and their enemies in the fifteenth century. The huge siege bombards, possessed by most of the great cities at the end of the fourteenth century, were too cumbrous for transport. Built up of welded and coiled iron, and therefore without trunnions, they were replaced, toward A.D. 1443, by lighter pieces on wheeled carriages. And before the Burgundian War “coulevrines de campagne” were being cast in Switzerland, of bronze, with trunnions to give each piece an elevation independently of its carriage. Relics are still preserved which show the gun-trunnion in its early stages, as embodied in the Burgundian artillery of Charles the Bold. The first method of obtaining elevation for the gun was by hinges or trunnions on the front of the carriage or trunk, in combination with a curved rack erected on the trail for supporting the rear end. Then the trunk disappeared; the trunnions were cast on the gun, whose cascabel was supported by a cross-pin between the flanks of the trail; and then the cross-pin was made removable, and a series of holes was provided for its reception, to give the elevation desired. At first these trunnions were cast level with the gun axis; in Napoleon III’s treatise on artillery is a picture of a trunnion gun taken by the Swiss from Charles the Bold in 1476, and another of a cannon of Louis XI, cast in 1478, and in both cases the trunnions are level with the gun axis. But pieces cast later almost invariably had their trunnions set on a level with the bottom of the bore; partly, perhaps, for the insignificant reason given by Norton—that “lying somewhat under the concave cylinder of the bore they will the better support the great weight”—but primarily to ensure a downward pressure on the quoin or trail when discharge took place. The effect of this trivial alteration was enormous. The impulse of the recoil was given a moment about the trunnion axis which, as the force of powders increased, produced an increasingly great downward pressure on the trail. Carriages, though made of massive scantlings, frequently broke; nor was it till the latter half of the eighteenth century that the cause was removed, the trunnions being raised nearer the axes of the guns and the carriages being thereby relieved of the excessive cross-strains which they had borne for nearly three hundred years. Muller, in his Artillery, refers to the “absurd method” of placing the trunnions so low and, in the year 1768, points out the advantages to be gained by raising them. “Writers do not appear to have had any idea,” says Favé, “of the effect which the position of the trunnions had on the stressing of the carriage.” Scharnhorst the Prussian gives as an important advantage to be gained by raising the trunnions, the larger wheels which could be employed without adding to the height of the gun above the ground.

Progress was also checked by the great length given to the smaller varieties of cannon. With the fine powder of the Middle Ages a great length of barrel was necessary to ensure complete combustion, and such primitive observations as were made all seemed to prove that, the longer the barrel the greater the range. But with the introduction of corned powder a reduction in length should have been possible. No such change was made. Tradition had consecrated long guns, and official standardization of types afterwards helped to oppose any innovation in this respect until the eighteenth century, with few exceptions.

To Charles V of Spain belongs the credit for the first systematic classification of guns. In his hands artillery had, for the first time, become an efficient instrument of battle in land campaigns, and all Europe saw that, in his batteries of bronze trunnion-guns, on wheeled carriages, firing cast-iron balls against foe or crumbling masonry, a new power had arisen.[66] The emperor, experiencing the inconvenience of a multiplicity of types and calibres, sought to simplify his material. Accordingly, in the year 1544 or shortly before, he approved seven models to which all pieces in use throughout the vast possessions of the Spanish monarchy were thenceforth to conform. These seven types comprised a cannon (a 40-pounder), a cannon-moyen (24-pounder), two 12-pounder culverins, two 6-pounder culverins, and a 3-pounder falcon.

The French soon improved on Charles’ example. The oldest patterns of their cannon, according to a table given by St. Remy in his Mémoires, were of a uniform length of ten feet. In A.D. 1550 Henri II issued an edict restricting the number of different calibres to six, named as follows:—

Canon, a 33-pounder, 10½ feet long, weighing 5200 livres, drawn by 21 horses.

Grande coulevrine, a 15-pounder, 11 feet long, weighing 4000 livres, drawn by 17 horses.

Coulevrine bâtarde, a 7-pounder, 9 feet long, weighing 2500 livres, drawn by 11 horses.

Coulevrine moyenne, a 2-pounder, 8½ feet long, weighing 1200 livres, drawn by 4 horses.

Faucon, a 1-pounder, 7½ feet long, weighing 700 livres, drawn by 3 horses.

Fauconneau, a ¾-pounder, 7 feet long, weighing 410 livres, drawn by 2 horses.

These dimensions are only a rough approximation. In the year 1584 two other types, found useful by the Spaniards in the Low Countries, were included—a 12- and a 24-pounder.

The relatively greater lengths of the small pieces will be noted. As it was with the French, so it was with other nations, and the list of Italian ordnance given in Tartaglia’s Art of Shooting shows a general resemblance to that of Henri II. The desire for a maximum of ranging power, and the necessity of making the smaller pieces long enough to enter the embrasures of fortifications, and strong enough to fire many more rounds than those of the largest size, tended to cause an augmentation in their size and weight; difficulties of transport had an effect in imposing a limit of weight on the largest guns which in the case of the smaller pieces did not operate to the same degree.

Nevertheless, the French possessed, from 1550 onwards, an organized artillery suitable for transport on campaigns. The six calibres were mounted on wheeled carriages, horse-drawn, from which they could be fired; they were moved, muzzles foremost, with their ponderous trails dragging on the ground in rear.

At that point French artillery remained, or with little advance beyond it, until the middle of the eighteenth century. In the Germanic states, on the other hand, important progress was made: by the end of the sixteenth century shorter pieces, shell-fire from mortars, and the use of elevated fire for varying ranges, had been adopted. But the chief centre of artillery progress at the end of the sixteenth century was the Low Countries, then in the thick of their warfare with Spain. “In their glorious struggle for independence their artillery contrived to avail itself of the latest and best theory and practice, to employ cannons and carriages of simplicity and uniformity; and it has endowed the art of war with two inventions of the first order—the hand-grenade and the bomb.”[67]