Dug-out with Roof Removed.
Dimensions variable. Note the wide berms permitting the use of strong roof supports. A layer of large stones to cause early shell burst should form part of the roofing.
Great care and attention must be given to these dugouts, and even though taking a little longer than seems necessary, care must be taken to see that they are substantially constructed, otherwise they are in a constant source of danger of cave-ins during heavy shelling and bad weather. Not more than 10 men should occupy one of these dugouts. Then, if accidents happen, your casualties are not so great.
The roof of these dugouts should be prepared in a manner tending to withstand as high shell shock as possible, and for this purpose the following table would be of some use, any part of which, or a combination of all, will give some idea of what is required.
RESISTANCE OF ROOFING MATERIALS
(a) Shrapnel bullets—Stout planks suitably supported and covered with corrugated iron and 12″ of earth or 3″ of shingle.
(b) Ordinary guns of 3″ caliber—Strong timber supporting 4 ft. of earth with a top layer of heavy stones or broken bricks to cause early shell burst.
(c) Field howitzers (of less than 6″ caliber)—12″ logs, supporting 8 ft. of earth with top layer of heavy stones or broken brick and lightly covered over with some earth.