First Day of the Somme

[PhilB]

What did these "effective" shells actually do to the wire? Did they they push it into the ground or blow it somewhere else?? How did it disappear from the attackers` path?

[centurion]

QUOTE (Phil_B @ Oct 9 2008, 02:39 PM) <{POST_SNAPBACK}>

What did these "effective" shells actually do to the wire? Did they they push it into the ground or blow it somewhere else?? How did it disappear from the attackers` path?

It was blown into small enough pieces so as not be an effective obstacle

[ian turner]

This was because there was a slight delay between the shell landing (and digging in) and exploding. The grazing fuse was invented (by the French) precisely to avoid this. It is also why the toffee apple proved to be a very effective wire cutter (once some fuse problems were solved) as it did not dig in but exploded on the surface.

Then there was the large number of duds from the British artillery - poor quality shell casing causing 'prematures', so much so that the gunners were not setting the fuses at all. Centurion, I think I am correct in saying that the Britsh graze fuse was none too reliable either?

Ian

[Desdichado]

There was also the number of guns used. Too few, some have said, to have the desired effect. If the British had half as many guns again as were in use during the pre-attack barrage, would it have made an appreciable difference of would the wire still have remained fairly intact?

[centurion]

Then there was the large number of duds from the British artillery - poor quality shell casing causing 'prematures', so much so that the gunners were not setting the fuses at all. Centurion, I think I am correct in saying that the Britsh graze fuse was none too reliable either?

Correct - I think the French fuse or a variety of it was used in the end.

[bmac]

The principle of the shrapnel wire cut was that the shell should explode just in front of and at an optimum height above the front edge of the wire. It also needed to be approaching the wire at the correct angle thus the importance of optimum range so that the shell's angle of approach was neither too steep nor too shallow. The explosion of the charge behind the shrapnel balls would propel them forward in a cone with the intention that the balls would cut and sweep away the wire. If the shell exploded too high the energy of the balls was quickly dissipated, too steep and they ploughed into the ground, etc., etc. Shells exploding too low showed up on aerial photographs as having scoured the ground.

Other problems were either known about and ignored or were relatively new. It was recommended that guns on wire cutting should not be used for anything else. As accuracy was all, if the guns were used for other shoots then it was likely to upset the accuracy of the wire cutting when they returned to it. There is plenty of evidence that wire cutting guns were used for general trench bombardment and interdiction, against advice. Then, these guns had never before had the supply of shells nor the length of time given for the wire cutting. This caused major stress to the guns: barrel wear, hydraulic issues, disturbance to platforms, etc., all of which messed with accuracy. And, during a shoot, the angle of the barrel had to be constantly changed as the barrel heated up. Also, at this time, meteorological conditions, wind, temperature, air pressure, etc., were not provided for the field guns. A huge learning curve for relatively novice gunners.

Then there was the two day delay caused by the weather. The general intensity of the bombardment and wire cutting was severely curtailed as there were concerns about conserving ammunition needed for the expected advance. This gave German troops an opportunity to repair and replace wire previously damaged. Furthermore, as the day of the attack drew closer, officer patrols were increasingly sent out at night to inspect the wire and, during these periods, the artillery was again silent thereby giving the defenders chances to repair damaged wire.

In some locations cutting wire by 18 pdr shrapnel was almost impossible because of the lie of the land and here the 'toffee apple' mortar was used. This had been shown to be very good at wire cutting but was:

1. a short range weapon subject to immediate German counter measures (and, therefore, very unpopular with the neighbouring infantry); and

2. in the hands of inexperienced gunners.

This inexperience led to the bombs often being launched from too short a range. The fuse was set by a pin piercing a cap when the mortar was fired but, if fired with too small a charge, the shock was insufficient and the fuse did not work. This led to scenes like the one that met the advancing men of the 6th North Staffs at Gommecourt where a field of orange 'footballs' (i.e. unexploded mortar bombs) was found in a previously unobservable area of uncut German wire.

[centurion]

This inexperience led to the bombs often being launched from too short a range. The fuse was set by a pin piercing a cap when the mortar was fired but, if fired with too small a charge, the shock was insufficient and the fuse did not work. This led to scenes like the one that met the advancing men of the 6th North Staffs at Gommecourt where a field of orange 'footballs' (i.e. unexploded mortar bombs) was found in a previously unobservable area of uncut German wire.

This problem was already known and a solution found ( a new fuse) long before the Somme. I enclose a link to an interesting first hand account of the problem. Toffee It also illustrates another problem of using field guns and shrapnel for wire clearing - that of avoiding hitting one's own troops.

I suspect that shrapnel for wire clearing would only be successful if

a] the guns were dedicated to it

b] the gunners were experienced and

c} the wire was not in dead ground

On the Somme in many instances none of these conditions were met.

[Robert Dunlop]

Shrapnel bullets could and did cut wire during the preparatory bombardment on the Somme. The effect of shrapnel used for this purpose on July 1 1916 was analysed by Major General John Headlam, who produced a report entitled 'Notes on Atillery Material in the Battle of the Somme', reproduced in 'Battlefront: Somme' (ISBN 1 903365 25 2). The report was dated 6 July and covered his analysis of the effects of the preliminary artillery bombardment before July 1. I quote:

"7. Wire cutting

The German defences on this front were known to be very carefully wired and the specimens attached will show the formidable character of the wire itself. In most cases, it was on iron uprights though in some cases wooden stakes were used.

Wherever it had been possible to obtain direct observation [my emphasis] it had been destroyed as an obstacle by artillery fire, and many infantry officers and men told me that they had never been in any way retarded by the wire or ever had to use the cutters on their rifles. The difference in the effect of the different natures of shell was, however, very marked. There is no doubt whatever in my mind that 18-pdr shrapnel is far the most generally effective projectile for this purpose. It sweeps the wire away completely without damaging the surface of the ground and so substituting another obstacle. This was very marked in front of the second line where 18-pdr fire had been used exclusively.

Next to the 18-pdr comes the 2" trench mortar with the Newton fuse. This is also very effective, but not so much as the 18-pdr for the wire is heaped up. In some cases 18-pdr had been employed to sweep away the wire which had been so heaped up by the 2", and this combination is extremely effective.

But the 18-pdr is not effective against wire on a forward slope (there was a very marked case of this near Fricourt where the fire had been very accurate, but little or no damage had been done to the wire), and there will also be those places where it cannot be reached by a flat trajectory gun and which are beyond the range of a trench mortar. Against such howitzers must be employed, and I was able to examine the effect of this in several places. The 6" howitzer is quite effective in removing the wire, but the craters left are a considerable obstacle to movement. The 4.5" does not appear to have a sufficiently violent explosion for the purpose, the wire being only blown away for a very small radius around the crater, so that there is considerable danger of the result being to increase the obstacle rather than the opposite. But this appears to be due to the effect of the explosion being confined to the crater. With the new instantaneous fuse (No. 106) I imagine that the effect will resemble that of the 2" trench mortar with the Newton fuse, and if so the power of the artillery to deal with wire will be materially increased.

As regards the nature of wire, it had been anticipated that iron uprights would render the task of the artillery more difficult. I am inclined to think that this is not so. Certainly in several cases the wire was cut away more cleanly and completely from the iron than from wooden stakes - possibly on account of the greater rigidity of the former. I am inclined to think that the most difficult wire to deal with is that on the iron knife rests as these are simply blown aside by the explosion without being broken up. Gaps can of course be made, but that is all."

Robert

[Desdichado]

This problem was already known and a solution found ( a new fuse) long before the Somme. I enclose a link to an interesting first hand account of the problem. Toffee It also illustrates another problem of using field guns and shrapnel for wire clearing - that of avoiding hitting one's own troops.

I suspect that shrapnel for wire clearing would only be successful if

a] the guns were dedicated to it

b] the gunners were experienced and

c} the wire was not in dead ground

On the Somme in many instances none of these conditions were met.

Three excellent points. Rawlinson's original plan called for the artillery, or at least selcted units, to concentrate on one target at a time until it had been destroyed. He was also concerned about the ability of the gunners arriving from England. He didn't so much mistrust their training but rather their lack of battle experience. He also thought that the front was too wide for the artillery to effectively neutralise the German positions and clear a path for the Tommies.

[nigelfe]

The principle of the shrapnel wire cut was that the shell should explode just in front of and at an optimum height above the front edge of the wire. It also needed to be approaching the wire at the correct angle thus the importance of optimum range so that the shell's angle of approach was neither too steep nor too shallow. The explosion of the charge behind the shrapnel balls would propel them forward in a cone with the intention that the balls would cut and sweep away the wire. If the shell exploded too high the energy of the balls was quickly dissipated, too steep and they ploughed into the ground, etc., etc. Shells exploding too low showed up on aerial photographs as having scoured the ground.

Other problems were either known about and ignored or were relatively new. It was recommended that guns on wire cutting should not be used for anything else. As accuracy was all, if the guns were used for other shoots then it was likely to upset the accuracy of the wire cutting when they returned to it. There is plenty of evidence that wire cutting guns were used for general trench bombardment and interdiction, against advice. Then, these guns had never before had the supply of shells nor the length of time given for the wire cutting. This caused major stress to the guns: barrel wear, hydraulic issues, disturbance to platforms, etc., all of which messed with accuracy. And, during a shoot, the angle of the barrel had to be constantly changed as the barrel heated up. Also, at this time, meteorological conditions, wind, temperature, air pressure, etc., were not provided for the field guns. A huge learning curve for relatively novice gunners.

Obviously there was a distance from burst after which the shrapnel bullets lacked the requisite residiual energy. For men targets is was about 300 yard.

For wire cutting the angle of descent needed to be flat so that the bullets got the maximum length of their trajectory going through the wire entanglements. If they were too steep it wasn't very efficient so more rounds were needed. This meant that for 18-pr (which was fixed charge like a rifle) there was an optimum range bracket of 2-300 yards or so, I have the exact ranges somewhere but can't quickly find them. Interestingly the 1917 edition of Notes No 4 added 5% HE to clear the cut wire away.

The reason fire had to be observed was that during a prolonged bombardment of the same target the fire drifted (as I said in my earlier post). This had nothing to do with the experience of the battery or it's soldiers (unless they were being a bit naughty with their aiming point selection and the ground was so soft that the guns were moving back a lot and not being repositioned back to their original one). It's because during the course of a day the meteorological conditions and charge temperature change, if they were firing serious amounts it might also result in discernable barrel wear that affects projectile stability and increases dispersion. This affects not just the data on the guns' sights (mainly elevation) but also on the igniferious fuze settings. I'm not entirely convinced that changing target and coming back was the real issue (indirect fire methods basically deal with this), I suspect it was mostly to do with the changing met conditions during a day. I'm also totally unconvinced (based on a lot of gunnery experience) that batteries recently arrived from UK were in anyway a problem - if anything they probably didn't have the odd bad habit that the old lags had! Such is human nature.

The term 'graze fuze' is a bit misleading. The graze function was actually a delay effect in modern terms, hence the excessive cratering. This confuses lots of folk who don't actually understand the British terminology of the period and make assumptions based on 'normal' English usage. No 106 was the first 'direct action' fuze in UK service, unfortunately the first version had a problem with its safe-arm arrangements and had to be rapidly withdrawn. A quick redesign resulted in the No 106E and all was well.

[Ghost]

Well Sir John cuts the mustard, hard to argue with him.

[centurion]

The term 'graze fuze' is a bit misleading. The graze function was actually a delay effect in modern terms, hence the excessive cratering. This confuses lots of folk who don't actually understand the British terminology of the period

I think you may be confusing modern terminology where many graze fuses in missiles are indeed a form of delay with WW1 terminology which meant instantaneous on impact. A good description of the situation in WW1 is given by Dr David Jordan of the IWM

A further problem was the failure of artillery fire to sever the barbed wire entanglements in front of the enemy defences. Shrapnel proved inadequate for the purpose, while high explosive (HE) shells did not explode on impact, causing craters without cutting the wire. By 1917, many of these difficulties had been overcome. After a false start with the Number 101 Fuze, which was faulty, British industry produced the Number 106 Fuze, which at last enabled instantaneous detonation of HE, which had the desired effects in terms of wire cutting.

[nigelfe]

The term Graze continued to be used in WW2. They had a slight delayed effect. Direct Action fuzes also cause craters but they are very shallow (a very few inches in normal ground).

No 101 was a Percussion & Graze fuze and continued in service, it was still in use with WW1 era guns in the early part of WW2 along with Percussion DA fuzes No 44, 106 and 115. In UK DA fuzes the impact crushed the nose which forced the firing pin back into the detonator, some fuzes (eg Krupp) worked the other way around, when the shell was retarded by sudden resistance the firing pin's inertia moved it forward into the detonator.

The best way to understand graze is the WW2 No 119 fuze, this was a DA & Graze fuze, for graze it was fired with its cap on (to nulify the DA function) which allowed it to penetrate light cover before detonating. WW2 also had No 232 which was 'Percussion Graze' and No 231 that was Pecussion Graze with Delay, this delay enabled it to be used to give richochet airburst (but needed a flat angle of descent). In WW2 some of the time (airburst) fuzes also had a percussion graze default action (Time & Percussion). In WW1 Time & Percussion fuzes were available for shrapnel and I think they were the normal fuze with at least some guns. This meant that shrapnel could richochet but then fired upwards. 18-pr shrapnel would penetrate an 5 ft parapet before bursting, 13-pr shrapnel would penetrate the wall of a normal house (which indicates the fuze was T&P graze). Shrapnel could produce ricochet bursts with the bullets going mostly upwards.

As I keep repeating and as has been highlighted by the Headlam quote (he was appointed BEF MGRA in late 1915 and knew what he was talking about, and also initiated GHQ Artillery Notes), shrapnel did cut wire, it just needed sufficient resources. The 1917 edition of Notes No 4 states it needed 7.5 rds of 18-pr shrapnel per yard of front (the 1916 figure was "the rough rule is to allow 1/3 the the number of hundreds of yards in the range for each yard of front"). The gunners were numerate regiment with numbers of officers with a scientific/mathamatical bent, we can assume they could do the arithmetic.

I found the 18-pr ranges, GHQ Arty Notes No 5, Wire Cutting, June 1916. It states the best ranges are between 1800 and 2400 yards, the fuze couldn't be set to less that 1000 yards (in time) and under 1800 there was the possibility that shell wouldn't clear the gun pit parapet. Wire could be cut at up to 3500 yards but a lot more ammo was required, above 3500 yard the bullets had insufficient velocity. Note the range bracket and the rough rule for quantity quoted above and the 1917 figure for quantity.

It (Notes No 5) also says "It is generally agreed that shrapnel is the most efficient projectile, but everything depends upon bursting the shell in the right place." Notes No 5 also includes 2-in Trench Mortar, howitzers and 60-pr for wire cutting.