CHAPTER IV
THE MARK I TANK AND ITS TACTICS
The Mark I tank was the direct produce of the experimental machine which was officially tested on February 2, 1916. It may be defined as “a mechanically-propelled cross-country armoured battery,” the maximum thickness of its armour being 12 mm.[17]
The main tactical characteristics of all tanks may be placed under the headings of—mobility, security, and offensive power, and as regards the Mark I machine the following is a general description of these characteristics:
(i) Mobility.—The Mark I tank could move over flat ground at 100 to 120 yards a minute, over ground intersected by trenches at 30 to 40 yards a minute, and at night time at 15 yards a minute. It could cross all forms of wire entanglements, crushing down two paths through them which were passable by two single files of infantry. It could span a trench 11 ft. 6 in. wide, surmount an obstacle 5 ft. high, and climb a slope of 1 over 2.
(ii) Security.—The Mark I tank was proof against ordinary bullets, shrapnel, and most shell-splinters.
(iii) Offensive Power.—Mark I tanks were divided into two categories: male and female. The former carried an armament of two 6-pounder guns and four Hotchkiss machine-guns, the latter of five Vickers and one Hotchkiss machine-guns. The normal amount of ammunition carried was for males 200 rounds and 10,000 rounds S.A.A., and for females 12,000 rounds S.A.A.
The chief limitations of the tank are connected with its mobility. For the Mark I type these limitations were as follows:
Its circuit in action was about 12 miles, and the fighting endurance of its crew 8 to 12 hours. It was not suited for traversing swamps, thick woods, streams with marshy banks, or deep sunken roads. It could be expected to cross shelled dry ground at a slow pace, but should this ground become sodden with rain it would find difficulty in doing so, and might frequently become ditched.
A tactical paper on the employment of this machine was put forward officially in February 1916 by Colonel Swinton, entitled “Notes on the Employment of ‘Tanks.’” This document is of special interest as it is the first tactical note published on the use of tanks. The following are certain extracts taken from it: