Artillery: corrector lengths and graze

[A Rankin]

Good morning all,

 

    I have been researching Fourth Army and the Australian Corps attack on the Hindenburg Line in Sep-Oct 1918 and have come across the instruction:  "corrector lengths are to be arranged in order to give 50% of time shell on graze" numerous times in artillery instructions for specific attacks.  From my reading on threads of this site and of Nigel's British Artillery in WW2 site, my understanding of the effect of this instruction is to reduce the time period for detonation, in order to optimize for cratering, penetration or ricochet.  I don't feel like I quite have the whole meaning though and would welcome any clarification.   The operation was for the creeping barrage before the 29 September attack.    The instruction is on page 9 of the uploaded document, which was from the War Diary of the 1st Australian Divisional Artillery (courtesy of the Australian War Memorial), which was supporting the 30th American Division in the assault.

 

Thank you

instructions 6-13 series 6 AWM4 13-10-48 Headquarters, 1st Australian Divisional Artillery September 1918 Part 1-5.pdf

Edited 29 December , 2017 by A Rankin
give attribution to uploaded file

[Crunchy]

I asked an RAA Gunner mate of mine and this is his reply.

 

"As far as I am aware, a corrector length is a correction (+ or -) to the fuze setting obtained from the range table for the range at which the guns are to be fired.  Ideally the range table setting would burst the round in the air just short of the target range so that the shrapnel balls would spread out and cover the target.  This may not happen in reality because of reasons such as the difference in MV of the gun from the range table standard or prevailing weather conditions.  A corrector length is applied by the observer to ensure the effect is achieved.

 

Just as the gun has a zone for range, so there is a zone for fuse action.  It seems to me in this case the shrapnel is being fired as part of the creeping barrage, and so in order to reduce the frequency of fuse action too far back along the trajectory (which would pose a danger to troops leaning on the barrage) the gunners are being told to use the corrector to ensure at least half the rounds do not function before hitting the ground.  Some of those that impact would function straight away, some would graze and function while ricocheting."

[A Rankin]

Crunchy,  thanks to you and your RAA mate for the reply.  That makes sense given the context, especially as many of the other contemporary documents noted the benefits of closely following the barrage, even at the expense of casualties from short rounds: this would hopefully minimize casualties.

[WhiteStarLine]

Chris has given us all the technical explanation.  By this stage of the war, artillery and infantry cooperation and shared experience allowed the distance between the shell bursts and the soldiers to be very close.  Sapper Dadswell layed line for both the attack on the outpost lines and the final breach of the Hindenburg Line.  He witnessed one such assault:

 

"On September 5th [1918] we went to Herbecourt and saw our guns put a creeping barrage on the side of the hill.  A line of shells burst near the foot of the hill and then crept forward.  A solid barrage of shells crept slowly up the hill, with the infantry following about eighty yards behind.  Few Fritz could escape that lot and I didn't see any of our infantry hit."