If now the Germans withdrew their guns further back to a position from which, though they cannot cover their front-line system, they can cover their second or third lines and simultaneously be immune, or to a great extent immune from our counter-battery fire, by accepting the loss of a small belt of ground they would place our attacking infantry in such a position that whilst it feels the full effect of their artillery, it is receiving next to no protection from its own.
The construction of their defensive systems in 1917 did not altogether lend itself to these tactics, the systems were too close together; but should these distances be enlarged the disadvantage to the attacker becomes apparent; and there were already signs that the Germans were fully aware of the advantage of this enlargement. At Arras they had been surprised in spite of the lengthy bombardment and they lost over 200 guns, at Messines they lost 67, and later on at Ypres only 25, on the first day of each attack. They were, in fact, countering by gun fire the exploitation of a penetration. This system of tactics can be graphically illustrated as follows (see [Diagram 16]).
DIAGRAM 16.—GERMAN ARTILLERY TACTICS.
Suppose that AB be the German front-line system, and that CD, their second line, be so placed that the German guns at E can heavily shell the whole of CD, and yet, on account of the distance away, remain practically immune from our guns at F. Suppose also that the area ABCD is strongly wired and well sprinkled with machine guns, who is going to suffer most—the attackers from GH, who will not only be perpetually worried by the machine guns and sharpshooters in ABCD, but who will come more and more under the enemy’s gun fire as they proceed towards CD, or the enemy’s machine gunners occupying ABCD, and his infantry in dug-outs along CD? Undoubtedly the former, for they present the largest target, and against them is being thrown the greater number of projectiles. Suppose now the attackers capture CD, then at best they will only be able to remain there as impassive spectators to their own destruction until such time as the guns at F move forward, which, on account of the “crumped area,” ABCD, will take many days. This is probably what would have happened had the Second Army been required to push the attack from the Oosttaverne line towards Wervicq.
Except for an attack on an objective of very limited depth the artillery attack was almost doomed to fail on account of slowness of moving forward the guns, due to the destruction of roads and terrain during the initial bombardment. Bearing the above possibilities in mind, it was with some apprehension that the Heavy Branch watched the approach of the next great battle, for though the “crumped” area could, if dry, be crossed by tanks, whatever service they might afford would be rendered useless on account of the impossibility of keeping the attacking infantry supplied; to do so, fleets of supply tanks would be required, and these did not exist.
CHAPTER XV
THE THIRD BATTLE OF YPRES
Towards the middle of May it was decided that all three Brigades of Tanks, that is, the whole Heavy Branch, should take part in the forthcoming operations of the Fifth Army east of Ypres, and that two of these brigades should assemble in Oosthoek wood and the third at Ouderdom. To initiate preparations an advanced headquarters was opened at Poperinghe early in June, and on the 22nd of this month the brigade advanced parties moved to the Ypres area.