GUN-PITS FOR FIELD-ARTILLERY.
THE FRENCH GUN-PIT.
Description.—The French gun-pit consists of an epaulement, whose general direction is perpendicular to the line of fire, with wings or returns at the sides, along which trenches are dug on the inside for the protection of the cannoneers. The earth for the epaulement is taken from a rectangular pit one and a half feet deep, and from the ramps and trenches leading to it. If there is not sufficient earth, more is obtained by digging a ditch in front. The lateral trenches may be prolonged and deepened to any extent.
Fig. 136.
Construction.—To trace the pit:
1. Lay off a line about ten feet in length perpendicular to the line of fire, to mark the foot of the interior slope of the epaulement.
This line should be long enough to give the piece a field of fire of 90 degrees; mark the extremities and centre of the line with stakes or otherwise.
2. In the wings lay off two lines five to seven feet in length, making with the first line angles such that the trenches shall not restrict the field of fire or interfere with the recoil of the piece.
3. Complete the rectangle of the pit, and mark the points of intersection of the trenches and the ramps leading to it.
4. In soft ground it will be found to be more expeditious to use shovels; if the ground is hard, three picks and five shovels will be necessary for each detachment of eight men. The men should commence by breaking ground along the interior slope; having picked a breadth of about two feet, they face about and advance toward the rear of the pit.
As soon as there is room the shovels follow the picks.
In picking the men should be instructed to strike together to avoid accident.
Under pressure this pit can be constructed in one and a half hours.
THE GERMAN GUN-PIT.
The German gun-pit consists of a rectangular excavation one and a half feet deep, with a ramp leading to it from the rear. The epaulement is formed like an ordinary glacis, and surrounds all but the entrance.
This pit is easily and rapidly constructed, and, as seen from a distance, presents a very small target.
The parapet being the same height all round, the gun can fire in any direction by widening the pit, which would then take the form of a semicircle.
Construction.—1. Lay off a line four yards in length perpendicular to the direction of the line of fire. At each extremity erect a perpendicular of four yards.
2. From the vertices of the right angles thus formed lay off one yard on both the front and side lines, and mark the four points so determined, together with the rear extremities of the sides, with sabres or stakes.
Fig. 137.
3. Commence and continue the digging as prescribed in the construction of the French gun-pit.
The pockets aa are for the reception of ammunition.
4. The ramp is laid out and completed after the pit is finished, or simultaneously with it, as may be most desirable.
An ordinary gun detachment can construct this pit in one hour.
THE AUSTRIAN GUN-PIT.
A simple rectangular pit one and a half feet deep, with front epaulement and ramp.
Construction.—Constructed similarly to the German, the earth from the pit being thrown to the front.
It can be made in less than half an hour, and while affording no special cover to the cannoneers, as do the German and English, it can be made in half that time, and does not present a conspicuous target.
Fig. 138.
It has the further advantage of very rapid cover, and of being capable of transformation into any desirable pit if there be time.
THE ENGLISH GUN-PIT.
This type is a true "gun-pit," the bottom being below the natural surface of the ground, sloping up at back of pit toward the rear. It affords excellent cover for the piece and its detachment, can be readily marked out, and constructed in a comparatively short time.
The lateral trenches, if extended, would afford a covered way along the front of the battery.
The defects in this pit are a contracted field of fire, the conspicuous mark which the embrasure gives the enemy, the lack of ammunition-pockets, and want of drainage.
Fig. 139.
Construction.—1. Lay off 8 feet 6 inches on a line perpendicular to the probable direction of fire for the interior crest, and at the middle point of this line determine a perpendicular to it; on this perpendicular lay off from the interior crest distances of 6 feet, 10 feet, and 18 feet, and through their extremities determine lines parallel to the interior crest; on these lines find points that are 6 feet from the perpendicular on both sides of it, putting in a stake or sabre at each point so determined. Extend the parallels at 6 feet and 10 feet, 4 feet on each side, and mark the points thus established for the lateral trenches.
2. Commence excavating at the interior crest, throwing the earth to the front and sides (being careful to allow a berme of about one foot), thus forming an epaulement 1 foot 6 inches high and 10 feet 5 inches thick at bottom, extending round to the front corner of the lateral trenches. Then throw the earth out to the side front to form mounds about 4 feet high in front of the lateral trenches to still better protect the detachment, sufficient space being left in front for an embrasure. Dig down two feet throughout the pit back to the line 10 feet from the interior crest and level off the bottom. Slope up from the bottom of the pit at ten-foot line back to the eighteen-foot line. If desirable to connect adjoining pits of this class, extend the lateral trenches until they meet.
Time of construction of pit complete in all its details, with detachment of eight cannoneers, gunner, and chief of section, in stiff clay, without previous practice, one hour and twenty minutes.
ORDINARY RUSSIAN GUN-PIT.
This type differs from the gun-pit proper, in that the wheels rest on the natural surface of the ground, the side-pits being for the cannoneers. The only apparent advantages are good cover for the detachment under heavy fire, drainage as far as the piece is concerned, and facility for ingress and egress. The obvious disadvantages are contracted space for working party in digging, contracted field of fire, and the mark presented by the embrasure to hostile fire.
Construction.—Lay off on a line perpendicular to the probable direction of fire 10 feet, prolong the line 5 feet 3 inches in both directions, and mark the four points thus determined with stakes or sabres. At the middle point of the ten-foot line erect a perpendicular to it and lay off on this perpendicular to the rear 9 feet 2 inches; through this point determine a parallel to the ten-foot line and lay off on it, on both sides of the perpendicular, 9 feet and 14 feet 3 inches, marking the four points so determined with stakes or sabres.
The parallelograms whose vertices are thus established fix the surface-lines of the lateral trenches. Dig down to 4 feet 6 inches for the bottom of the trenches and throw the dirt to the front and side, giving the epaulement a height of 3 feet, and leaving space for the embrasure in front. When time permits, cut outside and rear steps for the trenches, as indicated, to admit of quick egress for the gun detachment.
Fig. 140.
Time of construction complete, soil and detachment same as English pit, two hours.
GENERAL OBSERVATIONS ON GUN-PITS.
In forming the epaulement, leave a berme of at least a foot; and, when there is time, level and ram the earth, which, in front of the muzzle, should not be more than three and one half feet above the bottom of the pit. If there are side trenches, the earth in front of them should be high enough to afford complete protection to the men occupying them.
Pockets for the reception of the ammunition are very important in saving the ammunition from water which may accumulate, and from the fire of the enemy.
The field of fire should not be less than 90 degrees.
Avoid narrow embrasures as presenting an easy mark, and as likely to draw the fire of the enemy.
Cover should first be provided for the men and horses; then for the material.
If the position is occupied for some time, strengthen the parapet by earth from a ditch in front. Prolong the lateral trenches of the adjacent pits until they meet, forming a continuous parapet; if possible, plank or macadamize the bottom of the pit. Traverses between the guns will be found effective.
In order to conceal the parapets, cover the fresh earth with boughs, sod, or top-soil of the prevailing or surrounding color. If in winter, use snow for this purpose. A very effective plan is to dig a small trench or parapet from fifty to seventy-five yards in front of the real pits, thus deceiving an enemy as to where the real fire comes from.
If the ground does not afford natural cover for the limbers, limber-pits, similar to the Austrian gun-pits, can be easily constructed. They should be one foot deeper.