The cart was designed to illustrate an attempted solution of the problem of "How, in these times of rapid-firing arms of precision, shall the infantry fighting line be supplied with ammunition?" Before discussing the device, it will be well to briefly glance at the main limiting conditions of the problem, and incidentally at the way they are generally met.
On the march there is, of course, no more difficulty about transporting ammunition by animal draft than about moving any other weights; but after the fight begins, animals cannot be depended upon to get nearer than 2000 yards to the enemy's position, while the ammunition will be wanted well up to the front—wherever the line may be when the regular person-borne supply begins to run out—anywhere from 600 to 1200 yards from the hostile lines.
The Systems of the French and German armies may be quoted as examples of the generally approved methods for supplying the fighting lines. In these armies, apart from the ammunition regularly issued to the troops, the entire field supply transported in the battalion ammunition wagons, company baggage wagons, ammunition columns, and park reserves, amounts to 99 and 97 rounds per man, of which 18 rounds for the French and 20 rounds for the Germans are carried in the battalion ammunition wagons.
The German regulations provide that, "Before action is commenced, the ammunition wagons of a regiment are united under a mounted officer, in a secure position about 900 yards in rear of the fighting troops. In case of need they must be taken to the fighting line regardless of loss. The cartridges are taken to the front by men from each company; and supports sent on to the fighting line should take with them cartridges for those already engaged."
In the French army the rule is, "In action the battalion ammunition wagons are grouped together not more than 1100 yards to the rear. In case of necessity they may be ordered right up to the fighting line. Cartridge-bearers must be furnished by the companies in reserve, and are provided with double haversacks, kept in the wagons, and capable of containing 360 rounds. After carrying the ammunition to the fighting line and distributing it, the bearers must return for more."
Of these two typical systems it may be remarked that, if the line to be supplied was up within 800 yards of the enemy, the attempt to take animal-drawn wagons up to it in the face of the fire of fairly good modern-armed infantry—no matter how great the need might be that "they must be taken to the fighting line regardless of loss”—would prove very expensive in men, animals and material, and would result in little, if any, ammunition supply to the line.
In regard to the ammunition-bearers, it is to be noted that their chance of arrival is better than that of the wagons, in the proportion that the target exposed by a man is harder to strike than the one presented by a team; and that it requires a bearer for each 360 or 400 rounds carried from the wagons to the line.
Assuming, then, that men, not animals, must be employed within effective ranges, the question for consideration becomes one of advancing a given amount of ammunition from 800 to 1400 yards across a fire-swept zone and distributing it to the line in the shortest practicable time and with the greatest economy in the use of the ammunition detail.
The accompanying illustrations show that the device employed in the experimental vehicle is the using of specially constructed wheelbarrows, capable of being coupled together to form a cart for animal draft on the march, and readily uncoupled for man-propulsion across the fire-swept zone. As the barrow has but one point of contact with the ground, it is readily passed around and between obstructions, and can be taken nearly anywhere that a loaded ammunition bearer can go, while it is to be borne in mind that if the barrow be stopped by an obstacle impassable for it, but practicable for bearers, the bearers may be used from the obstacle to the front, instead of all the way from the train to the fighting line.
In regard to economy of time and ammunition detail, it has been found by experiment that, under ordinary service conditions of ground, two men with a barrow can move 4000 rounds a half mile in less time than they can carry 800 rounds the same distance.
When deep mud or very steep up-grades are encountered, the advantage of the barrow is decreased; on fairly firm turf, on hard ground, and on easy down-grades, it is increased. Averaging conditions of ground, the barrow has, in economy of time and men, about 5 to I in its favor over the borne-ammunition method.
These barrows are provided with a mechanical distributing device, by which the ammunition can be dropped at will in lots of two hundred rounds for each pull on the handles, and an automatic attachment by which the same distribution unit is dropped at each revolution of the wheel, so that the distribution can be made with the barrow-men on a dead run, and their time of entire exposure to fire decreased to a minimum.
The distributing device is a simple ratchet lever and draw-bar arrangement which releases in succession the traps which form the bottoms of the cells, each of which contains a unit of distribution of 200 rounds. The succession of the several releases is such that the center of gravity of the whole barrow-load is never altered, except by an amount due to the dropping of one unit of distribution, an amount which is entirely corrected as the next unit falls.
The device is simple and not liable to get out of order by exposure to weather, dust and mud; still it is not wholly positive in its action, since a return-spring is used to save the man from having to think of a necessary movement. On the whole, the mechanical distribution, although it does save time under fire, is of doubtful utility, because it might unexpectedly fail in its functions, and because the use of it, no matter what may be the distribution unit employed, demands the cellular arrangement of the barrow-caissons.
It would seem preferable to employ a light angle-steel frame instead of the caissons, the frames arranged to receive 500 round wooden factory boxes of the proper dimensions for use on the barrow. In such boxes the cartridges would be collected in good packing units for factory and depot accounting and stowage purposes, in packages not too heavy for a man to pick up and carry some distance, in convenient bulks for rail or other transport; and they would be always ready for quick transfer to the carts, formed of barrows, would keep dry when so transferred for any length of time in any weather, and would never leave their factory packing until they were delivered to the troops on the fighting line or anywhere else.
When the boxes were placed on the carts the cover-screws would be removed and the covers held in place by the angle-steels and retaining bolts only; so that, when a box was thrown off on the line, the men could get at the cartridges without having recourse to the always lost and much inquired-for screw-driver.
It is doubtful whether the fore-and-aft barrow-shafts are preferable to the cross-bar arrangement shown in Plate V. The shafts allow the barrow to pass through long, narrow spaces and separate the barrow-men more while distributing along the line, although they place one man directly in rear of the other in the advance to the line; the cross-bar is simpler of construction, gives better side support, and allows shorter turns to be made. On trial through ordinary New England woodland there was no very noticeable difference in the ease with which the way among the trunks and stumps could be threaded, whether using the shafts or the bar.
As the barrows are emptied of ammunition they may be thrown down upon the field as the detail joins the fighting line, and collected to couple up into carts after the action. The use of the empty barrows in clearing up the field reduces the stretcher detail one-half, since with a barrow with stretchers rigged (Plate VI) a detail of two can take two wounded to the hospital, or two dead to the trench, in less time than it can take one on a borne stretcher. As was satisfactorily shown on trial at Governor's Island, there is no difficulty whatever in using the barrow with only one stretcher loaded when collecting the wounded or dead.
The empty barrows with stretchers in place could upon occasion be used for moving sand-bags, or fire-wood, or for any small transport work about the field.
The shaft frame for animal-draft of this cart was made to take two barrows with the folding shafts shown in the illustrations, and for such barrows the travois-like arrangement answers the purpose fairly well.
In a design for a trial of the barrow device abroad, a pole replaces the shafts, the travois extension from the cross-piece is not used, and four barrows, the two outer ones tracking with the field artillery, are coupled to the cross-piece by eyes and bolts, and held normally at right angles to the pole in the vertical plane by spring struts, which allow a certain amount of independent vertical motion to the barrows, for the purpose of decreasing lateral strains when any one of them passes over an obstruction such as a stone or a stump.
With such a battalion cart, two good horses, with the driver mounted on the near one, can take 16,000 rounds—a 20-round supply for a battalion 800 strong—over country impassable for a wagon, and have the ammunition always ready for rapid distribution by an eight-men detail.
The general design of the barrow with the large wheel, centrally borne load and consequently small axle, was originally worked out to provide a means for allowing a reduction in the large draft-crews now necessary for the machine guns and one-pounders in our naval landing parties, and for decreasing the targets presented by the pieces in action.
Take the service one-pounder as an example. The piece, the trail mount consisting of low support socket, pivot and recoil brace, and 100 rounds of ammunition, loaded upon a barrow, could be taken over rougher country than is practicable for the present field carriage, and on the march the crew of six men would be obliged to exert less effort per man than does the present crew of double the number.
In going into action, the barrow could be rushed forward to an ordinary shelter trench made by the advanced infantry, the piece tripod and ammunition boxes thrown off, the barrow thrown down on its side, the piece mounted on its low mount and served by its crew lying down, and thus as much invisibility and cover secured from a 22-inch shelter trench parapet as it gives to infantry.
Or the piece and mount could be placed on one very light barrow, and the ammunition—150 rounds—on another. On the march the two could be coupled together, or handled separately, according to conditions of route. In the rush forward into action, the barrows would be manned separately with a crew of three men each, which would allow them to arrive if each crew lost a man in the advance.
Of course, the use of barrows is applicable to any pieces which must be gotten well forward to have them effective, and which must expose as little target as possible in order to be able to remain well forward. Such rifle caliber machine guns as the Maxim, the Pratt Whitney, the Gardner, and the Nordenfelt can be handled in like manner to that above described for the one-pounder. The Gatling and its ammunition can well be transported on the barrows, but that gun cannot be served by a prone crew, because the mount must be waist high, and the crank-man must stand in order to be able to put his full effort on the crank and so bring out the full power of the piece. Although the barrow-wheel has a large diameter, the barrow frame is so narrow that the whole device would stow better and occupy much less available space aboard ship than does the trail carriage; and the arrangement of the load is such as to allow its separation into convenient weights for stowing in boats, or for passing across or over streams, marshes, ditches and walls.
The system will be tried abroad, and if approved by foreign navies, may then, possibly, be domesticated in our own service.
TITLES OF PLATES—KIMBALL AMMUNITION VEHICLE.
No. I.—"Ammunition detail to the train!" Men at the cart.
No. 2.—"Unlimber and advance to the line!" a. Unlimbering; d. Advancing.
No. 3.—"Obstacle! Double the detail to pass!" a. Passing obstacle; d. Barrow awaiting return of double detail after a has passed obstacle.
No. 4.—"On the line and distribute!" a. Automatic distribution, dropping 200 rounds at each revolution of the wheel; d. Distribution at will.
No. 5.—Shafts and distributing gear carried away. "Distribute by hand! Forward!" a. Distributing by hand; d. Forward.
No. 6.—After the action. "Clear up the field!" a. Barrow as thrown down after being emptied when the detail joined the fighting line; d. Wounded to hospital, or dead to the trench.