Obstacle Crossing Demonstration - 1942

Part 1

This demonstration was held during mid-November 1942 in Tunstall Forest, in the vicinity of Fazeboons, just to the north-west of Sudbourne.  It was one of the most comprehensive demonstrations of its type held up to this date.


The object of this demonstration was to show some of the methods which could be employed to deal with obstacles (both anti-personnel and anti-tank) in the modern battle. The ground for the demonstration was chosen more for a good view point for spectators rather than ideal ground on which to attack over. The demonstration was limited in scope to a battalion front owing to a shortage of tanks and ammunition (it was a live firing demonstration).


The narrative assumed that the enemy had been pushed off ‘Grandstand Ridge’ on the evening of Nov 11th and were now holding positions on the forward slope of ‘Forest Ridge’, protected by a series of artificial obstacles. The enemy was assumed to be at only 40% strength due to previous fighting.  On Nov 13th 198 Infantry Brigade was to capture ‘Forest Ridge’ with the view of driving the enemy out of Tunstall Forest. The narrative was for a two battalion front, but as noted above practicalities limited this to a battalion front (the second battalion being ‘imaginary’).


The successive obstacles to be dealt with by troops in the demonstration were:

  • A belt of wire consisting of consecutive entanglements

  • A minefield, 60 yards deep, consisting of 10 rows of Mk IV anti-tank mines at seven yard spacing. The mines were unarmed.

  • A drainage ditch

  • An anti-tank ditch, V shaped, 15 ft wide and nine ft deep

  • A second belt of wire (as in the first)

  • A minefield , 110 yards deep, consisting of 12 rows of Mk IV mines at 12 yards spacing. The mines were armed but not fitted with  sorbo rings.


The narrative assumed that patrols and day reconnaissance  (both air and ground) had  located all the obstacles except the furthest minefield although this was approximately known due to interpretation of aerial photographs.


The demonstration was to be in two phases:

  • A ‘night’ operation (when troops taking part would wear dark glasses), to clear lanes through the first minefield with a Polish No2 mine detector  (with a long handled search coil) and by probing, crossing the drainage ditch with wooden bridges for the infantry and passage over the anti-tank ditch by ramping (both by digging and by explosives)

  • A ‘day’ operation when two further means of crossing the ditch would be demonstrated (A Scissors bridge and fascines), the second belt of wire to be cleared using Bangalore torpedoes and the second minefield using Snakes. This was to be accompanied with a tank attack, advancing to the objective and taking a ‘hull down’ position to support the following infantry attack.


Live firing was to take the form of harassing fire to cover the noise of the ‘night’ operation. A barrage on a 600 yards front opening at zero hour by 25 pounders and 6” howitzers was to last for two minutes on the Opening Line then lift 200 yards per minute for two minutes to support the tank attack. A smoke barrage was to be fired on the left flank by 3” mortars to cover the infantry advance.






















                                                                                                                                                               Left: Map showing site of demonstration with barrage trace and 'imaginary'  

                                                                                                                                                               right battalion front.

                                                                                                                                                               Right: Barrage trace. Line AA = Ditch crossed by fascine.

                                                                                                                                                               Line BB = Explosive charge inAnti-tank ditch.

                                                                                                                                                               Line CC = Anti-tank ditch crossed by scissors bridge.

                                                                                                                                                               Line DD to FF = Anti-tank ditch crossed by hand ramping.

                                                                                                                                                               On lines DD, EE and FF second minefield crossed with aid of 'Snakes'.

















To give the units taking part a chance to practice for the demonstration, a second anti-tank ditch was dug to the north-east of the demonstration site. Snakes were also provided by CRE 54 Div for practice.


A corduroy road had to be constructed over the low lying ground to ensure tanks did not get bogged down on the day of the demonstration – on a trial one tank got stuck and took four hours to recover. Various designs of road were used but the most satisfactory over the marshy ground was:

(a) A layer of brushwood (fir tops) fascines approx  eight inch diameter  and six ft long laid to overlap in the middle of the road creating a 10 ft roadway.

(b) A layer of chestnut paling of two five ft wide coils.

(c) A layer of 10 ft by four inch diameter forestry poles laid touching as for docking of a bridge.

(d) a layer of chestnut paling as in b.


To enable tanks to cross the small drainage ditch, the ditch was filled with 10 ft forestry poles.


To enable spectators to view the demonstration, six tubular scaffolding stands were constructed with tarpaulin roofs. Each stand could take 120 spectators. A 20 ft high scaffolding tower was also built and trees cleared to give a field of view.


Another scaffolding tower was built for use as an artillery observation post.


The programme for the demonstration was as follows:

  • 1000: Spectators arrive and inspect sideshows.

  • 1100: Spectators assemble in stands for the demonstration.

  • 1115: Introductory broadcast

  • 1125: Infantry cut first wire obstacle, making six lanes each 12 ft wide.

  • 1140: Royal Engineers and Pioneers lift mines in first minefield. Royal Engineers ramp down anti-tank ditch and place explosive charges at ditch. Royal Engineers place Bangalore Torpedoes in place at second wire obstacle.

  • 1205: ‘Dawn’ breaks, explanatory broadcast.

  • 1215: Blow charges and Torpedoes. Tanks (two squadrons) cross start line.  Right squadron to include a fascine and scissors bridge and left squadron to be accompanied by three Snakes. Barrage commences.

  • 1218: Tanks reach and ‘Snake’ second minefield.

  • 1220: Barrage ceases. Infantry cross start line.

  • 1222: Tanks take up hull-down position.

  • 1230: Infantry reach objective.

  • 1240: Spectators permitted to look at cleared lanes.

  • 1300: Further inspections of sideshows.



Right: Valentine Tanks were used in the demonstration






















































































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