Manual of Military Training Part 92

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=1118.= In all brush weaving the following terms have been adopted and are convenient to use:

=Randing.=--Weaving a single rod in and out between pickets.

=Slewing.=--Weaving two or more rods together in the same way.

=Pairing.=--Carrying two rods together, crossing each other in and out at each picket.

=Wattling.=--A general term applied to the woven part of brush construction.

=1119. A hurdle= is a basket work made of brushwood. If made in pieces, the usual size is 2 ft. 9 ins. by 6 ft., though the width may be varied so that it will cover the desired height of slope.

A hurdle is made by describing on the ground an arc of a circle of 8 ft. radius and on the arc driving 10 pickets, 8 ins. apart, covering 6 ft. out to out, Fig. 15. Brush is then woven in and out and well compacted. The concave side of a hurdle should be placed next the earth. It wraps less than if made flat.

=In weaving the hurdle=, begin randing at the middle s.p.a.ce at the bottom. Reaching the end, twist the rod as described for a withe, but at one point only, bend it around the end picket and work back. Start a second rod before the first one is quite out, slewing the two for a short distance. Hammer the wattling down snug on the pickets with a block of wood and continue until the top is reached. It improves the hurdle to finish the edges with two selected rods paired, Fig. 16. A pairing may be introduced in the middle, if desired, to give the hurdle extra endurance if it is to be used as a pavement or floor. If the hurdle is not to be used at once, or if it is to be transported, it must be sewed. The sewing is done with wire, twine, or withes at each end and in the middle, with st.i.tches about 6 ins. long, as shown in Fig. 16. About 40 ft. of wire is required to sew one hurdle. No. 14 is about the right size, and a coil of 100 lbs. will sew 40 hurdles.

Three men should make a hurdle in 2 hours, 2 wattling and the third preparing the rods.

=1120. Continuous hurdle.=--If conditions permit the revetment to be built in place, the hurdle is made continuous for considerable lengths. The pickets may be larger; they are driven farther apart, 12 or 18 ins., and the brush may be heavier. The construction is more rapid. The pickets are driven with a little more slant than is intended and must be anch.o.r.ed to the parapet. A line of poles with wire attached at intervals of 2 or 3 pickets will answer. The wires should be made fast to the pickets after the wattling is done. They will interfere with the wearing if fastened sooner. Two men should make 4 yds. of continuous hurdle of ordinary height in one hour.

=1121. Brush revetment.=--Pickets may be set as above described and the brush laid inside of them without weaving, being held in place by bringing the earth up with it. In this case the anchors must be fastened before the brush laying begins. The wires are not much in the way in this operation.

=1122. Gabion making.--A gabion= is a cylindrical basket with open ends, made of brush woven on pickets or stakes as described for hurdles. The usual size is 2 ft. outside diam. and 2 ft. 9 ins. height of wattling. On account of the sharp curvature somewhat better brush is required for gabions than will do for hurdles.

=The gabion form=, Fig. 17, is of wood, 21 ins. diam., with equidistant notches around the circ.u.mference, equal in number to the number of pickets to be used, usually 8 to 14, less if the brush is large and stiff, more if it is small and pliable. The notches should be of such depth that the pickets will project to 1 in. outside the circle. The pickets should be 1-1/4 to 1-3/4 ins. diam., 3 ft. 6 ins.

long and sharpened, half at the small and half at the large end.

=To make a gabion=, the form is placed on the ground, level or nearly so, and the pickets are driven vertically in the notches, large and small ends down, alternately. The form is then raised a foot and held by placing a las.h.i.+ng around outside the pickets, tightened with a rack stick, Fig. 18. The wattling is randed or slewed from the form up. The form is then dropped down, the gabion inverted and the wattling completed. If the brush is small, uniform, and pliable, pairing will make a better wattling than randing. If not for immediate use, the gabion must be sewed as described for hurdles, the same quant.i.ty of wire being required.

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The gabion, when wattled and sewed, is completed by cutting off the tops of the pickets 1 in. from the web, the bottom 3 ins., the latter sharpened after cutting, and driving a carrying picket through the middle of its length and a little on side of the axis. See that the middle of this picket is smooth. Three men should make a gabion in an hour.

Gabions may be made without the forms, but the work is slower and not so good. The circle is struck on the ground and the pickets driven at the proper points. The weaving is done from the ground up and the entire time of one man is required to keep the pickets in proper position.

=If brush is scarce=, gabions may be made with 6 ins. of wattling at each end, the middle left open. In filling, the open part may be lined with straw, gra.s.s, brush cuttings, or grain sacks, to keep the earth from running out.

=1123. Gabion revetment.=--The use of gabions in revetments is ill.u.s.trated in Fig. 20. If more than two tiers are used, the separating fascines should be anch.o.r.ed back. Gabion revetments should be crowned with sods or bags.

The advantages of the gabion revetment are very great. It can be put in place without extra labor and faster and with less exposure than any other. It is self-supporting and gives cover from view and partial cover from fire quicker than any other form.

Several forms of gabions of other material than brush have been used.

Sheet iron and iron and paper hoops are some of them. The iron splinters badly, is heavy, and has not given satisfaction. If any special materials are supplied the method of using them will, in view of the foregoing explanation, be obvious.

=1124. Timber or pole revetment.=--Poles too large for use in any other way may be cut to length and stood on end to form a revetment.

The lower ends should be in a small trench and have a waling piece in front of them. There must also be a waling piece or cap at or near the top, anch.o.r.ed back. Fig. 21 shows this form.

=1125. Miscellaneous revetments.=--Any receptacles for earth which will make a stable, compact pile, as =boxes=, =baskets=, =oil or other cans=, may be used for a revetment. =Barrels= may be used for gabions.

=Canvas= stretched behind pickets is well thought of in a foreign service. If the soil will make =adobe=, or sun-dried bricks, an excellent revetment may be made of them, but it will not stand wet weather.

Knots

=1126.= =Square= or =reef knot=, Fig. 22, commonly used for joining two ropes of the same size. The standing and running parts of each rope must pa.s.s through the loop of the other in the same direction, i.

e., from above down ward or vice versa; otherwise a _granny_, is made, which is a useless knot that will not hold. The reef knot can be upset by taking one end of the rope and its standing part and pulling them in opposite directions. With dry rope a reef knot is as strong as the rope; with wet rope it slips before the rope breaks, while a double sheet bend is found to hold.

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_Square or Reef_]

=1127. Two half hitches=, Fig. 23, especially useful for belaying, or making fast the end of a rope round its own standing part. The end may be lashed down or seized to the standing part with a piece of spun yarn; this adds to its security and prevents slipping.

This knot should never be used for hoisting a spar.

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_Two half hitches_]

=1128. Clove hitch=, Fig. 24, generally used for fastening a rope at right angles to a spar or at the commencement of a las.h.i.+ng. If the end of the spar is free, the hitch is made by first forming two loops, as in Fig. 26, placing the right-hand loop over the other one and slipping the double loop (Fig. 27) over the end of the spar. If this can not be done, pa.s.s the end of the rope round the spar, bring it up to the right of the standing part, cross over the latter, make another turn round the spar, and bring up the end between the spar, the last turn, and the standing part, Fig. 25. When used for securing guys to sheer legs, etc., the knot should be made with a long end, which is formed into two half hitches round the standing part and secured to it with spun yarn.

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_Clove hitch_]

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=1129. Timber hitch=, Fig. 28, used for hauling and lifting spars. It can easily be loosed when the strain is taken off, but will not slip under a pull. When used for hauling spars, a half hitch is added near the end of the spar, Fig. 29.

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_Timber hitch_]