Cruciform strongpoints

[mjollnir]

Does anyone by chance have reference to a Royal Engineers War Diary in which 'cruciform' strongpoints are discussed and illustrated? Some time in the past I have actually seen a Field Company diary in which the layout and instructions for the strongpoints is discussed, but I no longer have that reference.

 

I know what they were and what they generally looked like - often conjoined shell craters - but it would be interesting to have the official guidelines.

 

I am researching the assault by 20th Division on Eagle Trench E of Langemarck on 20 Sept 1917 in which the Divisional HQ diary notes that 83rd F.C. R.E. were to dig several strongpoints on the day of the assault of 'cruciform' design.

 

Thanks!

[brianmorris547]

Please see this old thread https://www.greatwarforum.org/topic/33492-whats-is/?tab=comments#comment-269100

I am reading RE WDs at the moment (again) and will keep a look out. I have checked the WD of 11 DLI who were the Pioneer Bn for 20 Div on 20/07/1917 and who were to work with the RE.

Brian

[Chris Henschke]

This diagram is from SS 196 Diagrams of Field Defences, March 1918. I have some more from the September 1917 period and will dig them up for you.

Chris Henschke

[mjollnir]

Excellent - thanks very much to both of you! That's a great diagram and anything more you find would be much appreciated.

 

My grandfather was in a dismounted cavalry party attached to 83rd F.C. R.E in the days leading up to the 20 Sept assault and on the day itself. That evening 83rd F.C. were called forward to dig strongpoints at the S end of 60 Bde sector, on and just beyond Eagle Trench near White Mill - at 20.U.23-24. I'm imagining that the strongpoints would have been made by joining together shell craters in a plan approximating to the cruciform shape in the figure above. I'm really hoping to find aerial photos taken after 20 Sept of that reference point to see if the strongpoints can be made out - there are none of 20.U.24 online at the IWM so I think it will necessitate a visit to the aerial photo catalogue there to see what they have among the glass plates, and make an order.

 

The diary of the Div Pioneer Battalion 11/DLI is very interesting as they were doing the same work at other strongpoints a bit further N along the line of Eagle Trench. They were called upon to provide a Lewis gun anti-aircraft detachment and suffered a number of casualties in the process.

 

Thanks very much again!

[MikeMeech]

On ‎03‎/‎10‎/‎2018 at 18:29, mjollnir said:

Does anyone by chance have reference to a Royal Engineers War Diary in which 'cruciform' strongpoints are discussed and illustrated? Some time in the past I have actually seen a Field Company diary in which the layout and instructions for the strongpoints is discussed, but I no longer have that reference.

 

I know what they were and what they generally looked like - often conjoined shell craters - but it would be interesting to have the official guidelines.

 

I am researching the assault by 20th Division on Eagle Trench E of Langemarck on 20 Sept 1917 in which the Divisional HQ diary notes that 83rd F.C. R.E. were to dig several strongpoints on the day of the assault of 'cruciform' design.

 

Thanks!

Hi

Also note this page from SS135 of December 1916.

 

Mike

[brianmorris547]

In the WD of 447 FC, 50 Div RE, 21/08/1916:

Coy drilling and Sections laying out a S.P. in the form of a "Curciform Work". Has a very small diagram.

In Ancestry.co.uk War Diaries Browse Box -  RE -  50 Div - Piece 2821 Divisional Troops - p 695.

Brian

[Robert Dunlop]

Here is the description of cruciform strongpoints in the official history of the New Zealand Engineers, from the section on the Battle of the Somme:

 

'Though trenches dug on a circular pattern generally provide the easiest means of securing fire command in all directions, it does not follow that the lie of the country is always suitable for that class of Strong Point. Another type of construction often in use was the cruciform system, based on a central length of traversed trench cut towards the enemy with two smaller lengths, running off on either side, approximately at right angles in the shape of a rough cross. Fire from trenches laid out in this form can be trained in any desired direction, and machine-guns placed at the ends of the intersecting lengths ensure cross-fire on the attacker wherever he may be.

 

The cruciform system of construction was particularly well adapted to circumstances which called for the immediate provision of defensible positions capable of holding back enemy attacks for the time that had necessarily to elapse before a complete trench line could be dug. The side lengths prolonged and joined up became the main-trench line, while the central stem could be extended to the rear to act as a communication sap. In such a case as this, the Strong Points were always maintained as such after the completion of the through trench, and the hasty work of the first few hours was gradually improved and amended with more and better machine-gun positions until the post had attained full development as a centre of resistance. Such points are harder for enemy artillery to range on, and easier to conceal from the sky than closed circular works. Having in view the ultimate purpose of their existence, their final equipment should include stores of bombs, ammunition, food, water, wire and sandbags with the provision of Headquarters, telephone, and other dugouts necessary for a continued and successful defence. It will easily be seen that the general principles underlying the existence of the "Strong Point" remain the same in all cases, and so long as these are satisfied, minor questions of size and shape may be safely governed by the exigencies of each particular situation.'

 

Robert