SUPPORT TRENCHES AND SUPPORT DUGOUTS
A support trench is usually within 30 to 300 yards of a fire trench, and may serve the purposes of covering fire trenches by skilled riflemen or an indirect machine gun fire, but their main purpose is to shelter troops from observation and shell fire, and thus their main characteristics become the size and strength of ample dugouts. Troops in the support dugouts are at hand for three purposes: Firstly, replacing of casualties occurring in the fire trenches during normal times or a hostile attack. Secondly, holding the support trenches in case the fire trenches are taken by the enemy. Thirdly, in the event of an attack on the enemy’s trenches, leading the attack by moving forward over the heads of the occupants of the fire trench, or if the latter are leading the attack, to occupy at once the fire trench when vacated. For this reason it is of vast importance that there are accessible and commodious support dugouts and communications between the immediate support trenches and front line. If this is so there will be less chance of disasters to supports and reserves coming up to make good a successful attack. There must be support dugouts even in the event of there being no support trenches, and this is very often possible owing to the lay of the land. The strength and size of these dugouts entirely depend on tactical considerations and local conditions, which are generally decided by the staff.