To facilitate the working of a gun, it must be placed on a platform of stone, or timber and plank: but, as a temporary measure, when required to fire only in one direction, timbers to take the wheels will suffice. The usual inclination given to platforms, from the rear to the front, is half an inch per foot. Platforms on barbettes should be perfectly level, and their dimensions must depend on the extent of the lateral range which may be required.
In laying a gun platform, the first thing to be done is to fix the hurter, which may be a piece of timber 7 or 8 feet long, and 7 inches square, or a strong fascine 9 feet in length may be advantageously used. The hurter is intended to take the wheels, or trucks of the carriage when the gun is run out, and to prevent their damaging the interior slope of the parapet. The position of the hurter necessarily depends therefore on the steepness of the interior slope. The hurter should be placed perpendicular to the axis, or central line of the embrazure. Three, four, or five sleepers of from 6 to 8 inches square, are then laid, their upper surface on a level with the bottom of the hurter, and they are covered with two-inch planks, nailed down when three sleepers are used; but if there be four or five sleepers, the planks may be confined by two ribbands (which are pieces of wood of the same length, but weaker scantling than the sleepers) and the platform racked down with rack lashings at the proper intervals.
A rack lashing consists of a piece of 2-inch rope about 9 feet long, which is fastened to a stick 15 inches long, 2 inches wide at the head, with a hole in it to receive the lashing, and tapering to a blunt point: it is passed round the timber, and sleeper beneath, then twice round itself. The end of the stick is then put into the loose gromet so formed, and twisted round until the whole is firmly secured, when the stick is turned flat on the upper piece of scantling.
The gun, and mortar platforms for sieges are now made rectangular: the dimensions of the former are 15 feet long by 10 feet 6 inches broad; those of a mortar platform are 7 feet 6 inches long by 6 feet 6 inches broad. Mortar platforms are laid exactly horizontal, the front part being placed 5 feet within the foot of the interior slope of the parapet.
Madras platforms consist of two stout planks about 12 feet long; they are supported on two sleepers, having a transom in front. The planks are secured with a moveable bolt, or pivot to the front transom, slide freely on the sleepers, and are connected together in rear by two cross pieces parallel to the rear sleeper, one in front, and the other in rear of it. To the centre of these two cross pieces is bolted another 12-feet plank, called the trail-piece, of a width equal to the distance between the cheeks of a siege-carriage, which is supported on a sleeper in the rear. When the gun is to be traversed, the whole platform is moved on the sleepers on the pivots in front. These platforms are chiefly intended for a direct fire. Two wedges are required for this platform to form inclined planes for the wheels, in running the gun on, or off the platform. Each wedge is of elm, 3 inches thick, 2½ feet long, and 1 foot wide, with a block to give the requisite height, the block being 12 inches long, 4 thick, and 7 in extreme height.
Alderson’s platform.
The platform invented by Colonel Alderson, R.E., is 15 feet long, by 9 feet wide; and is composed of 46 similar pieces of timber (baulks) each measuring 9 feet × 5 inches × 3½ inches. Of these, ten are used as sleepers, and the remainder as planking. The weight of the platform (when 15 feet long and 9 feet wide) for guns is 15 cwt. 2 qrs. 14 lb. By addition of the small beams, this platform may easily be extended from 15 to 18 feet.
Dimensions, and weight of Platforms, for Guns, &c.
| Nature of Platform, and articles required. | Number. | Length. | Breadth. | Thickness. | Weight. | |||||
| ft. in. | ft. in. | ft. in. | cwt. qr. lb. | |||||||
| GUN, AND HOWITZER. | ||||||||||
| Sleepers | 5 | 15 | 5 | 5 | 4 | 2 | 1 | |||
| Planks | 20 | 10 | 6 | 9 | 2 | 7 | 3 | 22 | ||
| Ribbands | 2 | 15 | 4 | 4 | 1 | 0 | 18 | |||
| Rack-sticks, and lashings | 10 | |||||||||
| Total weight | 13 | 2 | 23 | |||||||
| MORTAR. | ||||||||||
| Covered with oak planks. | ||||||||||
| Sleepers | 7 | 7 | 6 | 6 | 6 | 3 | 3 | 7 | ||
| Planks | 10 | 6 | 6 | 9 | 3 | 5 | 1 | 22 | ||
| Ribbands | 2 | 7 | 6 | 4 | 4 | 2 | 10 | |||
| Rack-sticks | 10 | 1 | 3 | 15 | ||||||
| Total weight | 9 | 3 | 26 | |||||||
| Made entirely of fir. | ||||||||||
| Sleepers | 7 | 7 | 6 | 6 | 6 | 3 | 3 | 7 | ||
| Planks | 8 | 6 | 6 | 11¼ | 4 | 4 | 2 | 18 | ||
| Ribbands | 2 | 7 | 6 | 4 | 4 | 2 | 10 | |||
| Rack-sticks | 8 | 12 | ||||||||
| Total weight | 9 | 0 | 19 | |||||||
| MADRAS. | ||||||||||
| Wood work. | ||||||||||
| Side-pieces | 2 | 12 | 6 | 1 | 0 | 4 | 3 | 0 | 18 | |
| Trail-piece | 1 | 12 | 1 | 4 | 4 | 1 | 1 | 3 | ||
| Fore transom | 1 | 7 | 6 | 6 | 2 | 19 | ||||
| Hind transoms | 2 | 6 | 6 | 9 | 3 | 2 | 20 | |||
| Sleepers | 3 | 9 | 6 | 6 | 2 | 0 | 16 | |||
| Wedges | 2 | 2 | 7 | |||||||
| Iron work. | ||||||||||
| Long bolts, ⅞in. diameter | 2 | 11½ | 6 | |||||||
| Short bolts, ditto | 6 | 7½ | 11 | |||||||
| Total weight | 8 | 2 | 16 | |||||||