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CONFIDENTIAL! 
 
 FOR OFFICIAL USE ONLY 
 
 DEEP GALLERY SHELTERS 
 
 Translated at the Army War College 
 FROM A FRENCH STUDY 
 
 JULY. 1917 
 
 WASHINGTON 
 GOVERNMENT PRINTING OFFICE 
 
 1917 
 
HIS 
 
 War Department, 
 
 Document No. 632. 
 
 Office of The Adjutant General. 
 
WAR DEPARTMENT, 
 
 Washington, July 18, 1917. 
 The following notes on Deep Gallery Shelters are published 
 for the information of all concerned. 
 [661.1, A, G. 0.1 
 
 By order of the Secretary of War : 
 
 TASKER H. BLISS, 
 Major General, Acting Chief of Staff. 
 Official : 
 
 H. P. McCAIN, 
 
 The Adjutant General. 
 
 WAR DEPARTMENT, 
 Adjutant General's Office, 
 
 Washington, June 19, 1917. 
 To all officers of the Army: 
 
 You are advised that this and all subsequent documents of a 
 similar character, which may be furnished to you from this 
 office, are to be regarded as strictly confidential. They are to 
 be kept at all times in your personal possession, and are not 
 to be copied, nor are any parts of their contertt^', to W com-; ', ; 
 municated either directly or indirectly to the iJi'ess,' tibr to' any ' ' 
 persons not in the military or naval service, , oft tl<e'/ i>iiit(^ \'/> 
 States. In Europe these documents are not'ta be' ca/ried -rtito' ' ' 
 the front line trenches, nor farther to the front than the usual 
 post of the officers to whom issued. 
 
 Strict compliance with this injunction is enjoined upon every 
 officer into whose hands any of these confidential documents 
 may come. 
 
 By order of the Secretary of War: 
 
 H. P. McCAIN, 
 The Adjutant General. 
 3536"— 17 3 
 
 664379 
 
CONTENTS. 
 
 Page. 
 Object 5 
 
 Description and characteristics 5-6 
 
 General description 6-7 
 
 Interior arrangement and details 7-8 
 
 Principles to observe 8 
 
 Depth 8 
 
 Longitudinal strength of galleries 8 
 
 Precautions concerning entrances and descents 8-9 
 
 Ground sanitary measures 9-10 
 
 Defense of entrance •- 10 
 
 Exterior defense 10 
 
 Blockhouse traverses 10 
 
 Prepared traverses 11 
 
 Interior defense 12 
 
 Protection against grenades 12 
 
 Protection against gas 12 
 
 Detaikof y,h^ y^o^k 12-14-15 
 
 Diagrams J. ;. 6-7-9-10-11-13-14-15 
 
DEEP GALLERY SHELTERS. 
 
 CONFIDENTIAI.— FOR OFFICIAL USB ONLY. 
 
 OBJECT. 
 
 The question of shelters has become a capital one in preparing 
 sectors, because of the increasing intensity of bombardments. 
 As this bombardment is usually effected by medium and large 
 caliber guns, it is absolutely necessary that shelters destined to 
 protect troops be impervious to systematic and regulated fire 
 of 150 c. m. and to individual rounds of a 210 mortar. Experi- 
 ence has proved that shelters covered with logs and earth were 
 unable to resist heavy shells with time fuses. Only shelters 
 in mine galleries, called underground shelters, or deep dugouts, 
 can provide sufficient protection. Therefore they alone should 
 be used. 
 
 DESCRIPTION AND CHARACTERISTIC3, 
 
 Shelters in mine galleries mean shelters dug in virgin- soil, 
 with roof and walls forming a solid inclosure, firmly w^^d^c^' 
 against the earth by a strong frame. These frames are usually' 
 made of thick logs, squared (0-20 c. m. at least). The entrances 
 are also solidly framed by thick planks. 
 
 CHARACTERISTICS. 
 
 The means at hand in the field are sufficient to provide shelter 
 rapidly against projectiles of large caliber. They can be easily 
 constructed without arousing the enemy's suspicions, if pains are 
 taken to unload the earth sufficiently far away. They can be 
 constructed all alike, practically, the frames being of the same 
 workmanship, no matter how varying in size, and put together 
 
 6 
 
6 
 
 in the same way. The method of building and the supervision 
 of the construction is easy. Although they seem to take long 
 to build, they do not require longer than the ordinary log shel- 
 ters, which can only be worked on by day. Furthermore, as soon 
 as they have reached a few meters in depth they can be used 
 under favorable conditions. 
 
 rrcuTve. 
 
 Plank, fraoLA. 
 
 l/nteJ 
 
 TH iill is 'identical 
 
 t/prighi 
 .09 to Jo cm. At t/fe 
 
 b€iSC, 
 
 GENERAL DESCRIPTION. 
 
 l'ni?cbere^^rejd9\ibie\and single shelters. The single ones are 
 rtimost 't<nb . otily on/^ used, the double ones being reserved for 
 extraordinary cases far behind the lines. 
 
 Single shelter. — Formed by an underground horizontal gallery 
 communicating with the surface by means of two inclined en- 
 trances far enough apart to avoid both being affected by the 
 same shell. In order to diminish their length, the entrances 
 should be as steep as possible — 7/10 wuth ordinary frame, 1/1 
 with lined frame. 
 
 In order to permit leaving the shelter, even after the trench 
 has fallen into the hands of the enemy, a third opening should 
 be built whenever possible, coming out in rear of the parapet, 
 in a shell hole, communication trench, or tiench other than that 
 
containing the first two entrances. This last exit should be 
 carefully hidden or even filled with a mask of sandbags, which 
 can easily be overthrown from within. The shelters can also be 
 connected with observation posts and machine-gun emplace- 
 
 5he/ter 
 
 Bhe/ter 
 
 °fyr=\Uf 
 
 ;^£/n 
 
 tmnce 
 
 £ntrtuKe 
 
 nsz 
 
 ments by means of underground galleries. Each shelter should 
 be able to receive an entire unit — a half platoon, as a rule. If 
 they are smaller the number accommodated would not be pro- 
 portional to the time and energy expended. 
 
 Niches orbert/!3 
 
 rin rii rVi r'l 
 
 Pr//)c/pa/yaJ/ery, 
 
 Xi^^irrojice 
 
 lEnirojice 
 
 
 INTERIOR ARRANGEMENT AND DETAILS. 
 
 I. Each shelter must contain berths (double berths) for a 
 fraction of the unit occupying it. These berths are in the gal- 
 lery forming the main shelter or in niches dug perpendicularly 
 into the ground. This last method is preferable, as it allows 
 for the construction of niches without impeding the occupation 
 of the principal gallery, in case of need. 
 
8 
 
 II. Supply the shelters of the niche with hand grenades (the 
 single ones should each have the supply for one man), infantry 
 munitions, gas protections, food, and signal rockets. 
 
 III. Reserve a special corner for the platoon or half-platoon 
 leader. 
 
 IV. Construct chimneys for ventilation or to clear away the 
 smoke, with a draft to be shut at the bottom. 
 
 V. Watch the approaches to the shelter by a well-placed look- 
 out post and a periscope position. 
 
 VI. Prepare the defense of the entrances. 
 
 VII. Protect the interior of the shelter against grenades. 
 
 VIII. Protect the interior of the shelter from action of 
 asphyxiating gas. 
 
 PRINCIPLES TO OBSERVE. 
 
 DEPTH. 
 
 Above the dugout roof there must be a minimum of 6 meters of 
 virgin soil. If there are shell holes on the surface, go down to 
 8 meters. If water level prevents reaching 8 meters, reinforce- 
 ments are placed on the ground above the shelter made bj 
 (1) bed of logs, .20 meter in diameter, side by side, separated 
 by earth. (2) Cement blocks. (3) Bags of cement placed in 
 water for 10 minutes then placed side by side. (4) Bags of 
 cement mixed with pebbles and treated as above. The best 
 reenforcing is not as good as virgin soil. 
 
 LONGITUDINAL STRENGTH OF GALLERIES. 
 
 The length of the gallery should be carefully looked after. 
 
 (1) Nail the battens that join the uprights. 
 
 (2) Place four horizontal props at the joints of the frames in 
 each interval. The props must be strongly wedged and must 
 prevent any play. 
 
 (3) Make the length of the intervals .6 meter from axis to 
 axis of the frame. 
 
 PRECAUTIONS CONCERNING ENTRANCES AND DESCENTS. 
 
 (1) The last frame in the descent must be strongly supported 
 against the woodwork of the shelter. 
 
 (2) Place a number of tools and sandbags in each shelter, so 
 that an entrance can be quickly cleared in case of need. 
 
(3) Place a cord or rope the length of the descent to facilitate 
 the exit in case of obstruction, 
 
 (4) Nail a shaft to one of the supports or fix a tube so that 
 food and air may be obtained in case the entrance is destroyed. 
 There are certain precautions to be taken when ordinary frames 
 are used in descents to prevent the logs from rolling and the 
 frame from overturning. These precautions are as follows : 
 
 (1) Join the beams to the uprights by two oblique battens in 
 each corner. 
 
 /eeo/inffiJ<V)kA &>o/offiiJ!efy 
 
 finyf fp/aetd Mi^J«//)i) 
 
 ■Prop 
 SKUc/i ofa,^aJJery 
 
 />:>lch to ho/dj>rop 
 lfert/ca//fo/>y ^/ai 
 
 I^if.4: 
 
 rocffi^u 
 
 ^cfai/ of thejo/ning oft/ie 
 
 (2) Connect adjoining beams by two battens. 
 
 (3) Place diagonal braces in each interval of props to form 
 an irregular system of triangles. 
 
 The figure shows the plan of the arrangement of the logs in an 
 oblique descent and the junction with the gallery. There can 
 be no sliding or overturning of the frames with triangular prop- 
 ping. There is no harm in adding to the dimensions of the 
 wood and strength of the shelter. 
 
 GROUND SANITARY MEASURES. 
 
 (1) Whenever possible, drain off the surface water by ditcheo 
 and well-studied drainage. 
 
10 
 
 (2) Prevent the presence of dripping water by strong meas- 
 ures (sand bags, barriers, drains, higli ground), etc. 
 
 (3) There should be a small drain at the bottom of the 
 shelter, allowing for the working of a small drain pump. 
 
 tfie ^/^eci/'o/j otthe a/ff/e a.it.c. 
 
 Tif.S, 
 
 ■Prop 
 
 Ii piC' descent 
 
 6/'// of t fie fnzme o^the^af/ery 
 
 DEFENSE OF ENTRANCE. 
 
 Experience has shown that the units may be destroyed or 
 made prisoners in the dugout before they can get out. The 
 defense of the entrance to the shelter should be prepared. 
 
 EXTERIOR DEFENSE. 
 
 Exterior defense can be made by means of traverse block- 
 house. By the use of simple traverses, the portion of the com- 
 municating trench contained between the two traverses, fur- 
 nished with auxiliary defenses and latticework for grenades, 
 will keep the enemy out of the communicating trench. 
 
 Blockhouse traverses are made of large traverses, invisible 
 from the front, and containing a space allowing for fire and 
 bomb throwing on the dead angle not covered by the rifle. It is 
 a species of caponier established in the communicating trench. 
 Blockhouses are rarely used because of the difficulty in their 
 construction. 
 
11 
 
 Prepared traverses. — These are the simple traverses in which 
 a niche is dug out for a rifleman (seated or standing). A plat- 
 form for the grenadiers is constructed behind the traverse. Two 
 prepared traverses barricade or terminate the two exits of the 
 shelter. A wire entanglement, covered by several loopholes or 
 by the grenadier platform in the traverse, is placed along the 
 outside of the communication trench. A lattice against gre- 
 nades is placed above the communication trench. 
 
 r-i 
 
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 /Vt/Arm/brAv/Mt^/ar I p-j--,- 
 
 S/ftftar trM nic/ies. 
 
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 4i " " * ''.'•.•, : *<«^^^«>. 
 
 Mw/<fi/a//irv7ymd}es 
 
 -Ti^.e. 
 
 Grenade neitiny 
 
 ♦« ■ 
 6/>/e/(f.Suppor6ed by SojTdiaaS. 
 
 Firing Step for riffema/} ^t/tdtht 6hieJ<f 
 
 l^oot^e/) /ocfAo/e. 
 
 I"i^.7. ■ ^6cdoR of <if!r^ared Traverse 
 
 1. Niche in traverse for a rifle sweeping the bottom of the boyau and 
 a rifle firing 1.4 meters above the ground. 2. Platform for grenadiers. 
 3. Niche with loopholes enfilading the auxiliary defenses. 4—5. De- 
 scents to shelter. 6. Traverse between two descents to avoid the same 
 projectile striking both at the same time. 7. Wire entanglements. 
 8. Lattice against grenades. 
 
 The traverse blockhouses, with their covering of rails or 
 cement, have the same degree of solidity as the dugout. The 
 second arrangement, formed as a redoubt around the dugout 
 entrance, makes it easy for the occupants to get out. 
 
12 
 
 INTERIOR DEFENSE. 
 
 This defense can be assured by arrangement of obstacles, 
 one behind tlie other, placed in the descents — themselves either 
 at an intermediate or at the lowest point. The obstacle is made 
 by enlarging the descent and constructing a sandbag barrier at 
 the desired position. As the obstacles interfere with the light, 
 care must be taken in lighting the descent. 
 
 Protection against grenades. — Protection against grenades 
 must be added. The barrier of obstacles, one behind the other, 
 are not always able to keep the grenades from rolling into the 
 main part of the dugout. One of the following expedients may 
 be employed: 
 
 (1) A stationary panel with strong metal latticework is 
 placed in front of the barrier in the descent. The panel is pulled 
 up to the roof of the descent by means of a cord or wire w^hen- 
 ever desired, or lowered so as to completely obstruct the 
 descent. 
 
 (2) Furnish the entrance of the obstacle with a heavy plank 
 door. A landing place can also be built at the bottom of the 
 descent, from which a short ramp leads up to the shelter. The 
 grenade will then roll down to the landing place, but can not 
 get up into the shelter. This arrangement is inconvenient, as 
 the time and difficulty in constructing the dugout is considerably 
 increased. 
 
 Protection against gas. — Place cloths, impregnated with lin- 
 seed oil or parafin, or simply soaked in neutralizing solution 
 in the descent. The men's blankets are used if cloths are lack- 
 ing. Each descent should be furnished with two distinct 
 cloths placed at intervals of 1 meter. This permits the descent 
 to be hermetically closed to a sufficient degree and at the same 
 time allows passage. This arrangement is placed near the outlet 
 to prevent the accumulation of gas in the descent. 
 
 DETAILS OF THE WORK. 
 
 Frames. — For the descent — lining, 1^ by i^ meters ; ordinary, 
 li by lA meters or to by ra meter; inside dimensions. For 
 the body of the shelter, 1^ by Inr meters; diameter, ^ meter. 
 
 Roofing and lining planks. — One-twenty-fifth by eight-tenths 
 by a variable wadth. The thickest are for the roof. Larger 
 frames are used for the commanders' accommodation, with an 
 intermediate prop between the two uprights. 
 
13 
 
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 Slope for descent. — Lined frame, 1/1; ordinary frame, 7/10. 
 
 Working party for preparation of timber. — Five carpenters. 
 Two for saw, two for rough squaring, and one for making 
 mortices. This worlving party can make three frames an hour, 
 or even four with well-trained men. This working party also 
 cuts the lining planks and the wide battens. Tools : One large 
 
 £xampJe ofprotectioR a^ainBt ^renadee. 
 Oif^facJc ai the foot of the aescent 
 
 Cw^ section. 
 
 fllaunpart of 
 jg thesheJtcr 
 
 Plan onlinefi-J^. 
 
 or ex/'t. 
 
 -<»•*'_,_ t.fO 
 
 riy^. 
 
 saw, one crosscut saw, two axes, one adze, one carpenter's 
 chisel, one mallet, one meter rule. 
 
 Transportation of material. — ^Each working party carries 
 enough supplies to complete their interval (timber casing and 
 lateral bracing). 
 
 Tools: Ordinary pick and shovel, short-handled pick and 
 shovel. With each working party: One tenon saw, one plumb 
 
15 
 
 line, one measuring tape, one hammer, one augur, one mason's 
 level. 
 
 Removing earth : By means of sand bags or with small trucks 
 on wooden rails, or with cases sliding on the floor of the descent. 
 
 Progress of the icork. — Working party : The two descents are 
 begun simultaneously. When there are two working parties 
 they form in the middle of the shelter. With each working 
 party there are four men to six meters in width, six men to the 
 
 ^ro^s section aJongfthe code ofibe deeceat 
 
 TO ihe trenches. 
 
 n^.io. 
 
 shelters, and eight men to the main part of the shelter when it is 
 commenced. A working party works for 8 hours and rests 
 during 24. The entrance should be made in 2 days, and the 
 descent at the rate of 2 meters a day. The junction of the 
 descents and the main part of the shelter should be made in 2 
 days. The shelter should be dug at the rate of 2 meters a day. 
 Each working party makes one complete interval, la by i^ 
 meters, during its 8 hours, including timber casing. Fifteen 
 days is required for 12 meters of descent and 15 meters of 
 shelter. 
 
 o 
 
664379 
 
 U (r44 C 
 U 
 
 UNIVERSITY OF CALIFORNIA UBRARY