Nelson Evening Mail. SATURDAY, MARCH 2, 1918 TANKS AND TRENCHES.

Nelson Evening Mail, Volume LII, Issue 53, 2 March 1918, Page 4

Nelson Evening Mail. SATURDAY, MARCH 2, 1918 TANKS AND TRENCHES.

NOT only has the tank now risen to the of being one of the Allies' principal but it has actually produced a distinct change in defence entrenchment by causing trenches to be "built far wider in the attempt to stop ' the tanks' progress. The detailed accounts of the Cambrai affair make this 'clear. Incidentally they throw some i light on recent forms of German systems of defence. It is a question whether the defences in front of Cambrai '.can be regarded aa up to date, however, ;says the Telegraph. They seem to in•lude none of the "pillbox" structures i which constitute the framework of the defences in front of Ypres, and, taking it all round, they represent the orthodqx of parallel grouped trench lihes 'rather thdn von Arnim's Flanders system of defence in depth, by a wide belt .of fortifications so irregularly scattered 'as to bffer no distinct and definite target to the airmen spotting for the attackers' guns. But on the other hand, it can hardly be taken as certain yet that defence by line has been definitely I 'abandoned for defence in depth. It i may be that in the Cambrai defences connected trenches were still used merely because in that • area the German generals had not time and labour enough to introduce the latest system along the whole of the Western front. But it may also be that von Arnim's innovations are regarded as no more than , an experiment, which will not be copied elsewhere.. Certainly von Arnim, no [ 'more than any other German general | was able to hold the Allied armies when they decided to advance. He was able to make their advance difficult and slow, but so were the other German generals, who used the older defensive system. ■ In the Cambrai advance the tanks had to cross a section of the original Hindenburg line, not as it. was when British forces attacked it farther north, but in its most developed state. What the tanks found was three "lines" of trenches, built on the old principle. According to a correspondent, "the main trench of- the advanced line of the Hindenburg system was deep, narrow, very cleanly cut, and well built, with numbers of strong points, snipers' posts and s : o forth, -but apparently without dugouts. The main trench of the second line, 500 to 1000 yards behind (usually called the main line), was of immense width. Without having measured it carefully, I.guess it to be not less than' 16 feet'in most places from lip to lip, having been built so wide presumably for the express purpose of checking the Both at the front and rear the French descend« perpendicularly 'Some five feet to a broad bench or firestep, which is four or five feet above the level of the trench bottom. At places there are trench mortar positions and the like, whet's the trench widens out i.nto a great chamber of some 30 by 40 feet dimensions. Kverything about the trench is on the same colossal scale, with dug-outs of tlie usual type frequent at regular intervals along it. The third, or support, main trench is equally wide in most places, and is built on a similar plan. Besides these main lines the whole area, to a deoth from a mile alnd a half to two miles", is intersected with support and reserve and communication Frenches and countless minor works, .besides barbed wire in quantities almost rncredible. Tlio communication trenches are everywhere very deep, and narrow." After describing some of the incidental defences, including short stretches of trench at dominating points, connected with thij general system only by communication trenches in their rear, mention is made of the barbed wire entanglements. These were in many places "of extraordinary strength, not merely in the depth and complication of the belts, but also in the character .of the individual strands, soma of which were so thick as to be very difficult to cut with hand nippers, and so densely set with barbs over an inch in length as to be almost impossible, to take hold of. Before the great main line a deep belt of this wire was set well forward, the nearest edge some 50 yards from the trench, then between it and the trench a further deep belt t broken into islands and built in cunning patterns, with openings through which the defenders could sally. 'When the attackers penetrated the" front belt they would naturaly be herded to the openings between the islands, which, of course, were swept by machine-guns from corresponding points in the trench, or behind it.. ' It need only be added that the tanks lolloped over the whole system, as per usual.