Field Artillery planning data

[Chris Henschke]

Unfortunately, the only reference I have for the 18 pdr is the 1915 handbook.

I have searched the forum but can't find anything specifically to answer my question.

I understand the concept of the 50% zone but what would be the beaten zone for 18 pdr and 4.5" How batteries (6 gun batteries) at about 4000 yards, firing over level terrain?

For point targets and area targets? Does a battery converge?

(disregarding variables : wind, temperature, barrel wear, etc.)

Chris Henschke

[Pete1052]

Chris, my answers are based upon my U.S. Army field artillery experience in '77-'84, which has occasionally been misleading when applied to Great War artillery practices. To answer your question on the beaten zone, one would need the firing tables for those weapons systems to look up the probable error in range at the range you specify. As for your second question, sheafs can indeed be converged for point targets.

[Pete1052]

Probable error is an error that is exceeded as often as it is not exceeded. As an example, consider the 50 percent of rounds that have fallen over the mean point of impact. At some point over the mean point of impact a second line can be drawn splitting the overs into two equal parts. The distance from the mean point of impact to the new line is called one probable error. For any normal dispersion pattern, a distance of four probable errors on either side of the mean point of impact will include virtually all rounds in the pattern.

Range probable error is shown in the firing tables and can be taken as an index of the precision of the piece.

Field Manual 6-40, Field Artillery Cannon Gunnery

1 December 1978

U.S. Army

[johnreed]

Chris

First of all the two equipment:-

18 Pdr Single Charge system The 50% PEr for the 18 Pdr 38 yards long and 3 yards wide therefore the beaten zone for 1 gun is 152 yards long by 12 yards wide = the 100% PEr. Normally the 18 Pdr was deployed in a straight line position with 25 to 30 yards between (I will work on a 25 yards gun frontage) therefore rounds falling in a box 152 yards x 137 yards, which is 38 x 4 = 152 and Battery Frontage of 125 yards + 12 yards = 137 yards.

4.5 in Howitzer is a multi charge system made up of 5 Charges, Charge 1, 2, 3, 4 and 5.

Firing Charge 1 charge bags 2 to 5 removed

Firing Charge 2 charge bags 3 to 5 removed

Firing Charge 3 charge bags 4 to 5 removed

Firing Charge 4 charge bags 5 removed

Firing Charge 5 no charge bag removed

4.5in Howitzer range 4,000 yards Charge 1 50% PEr Length 23.3 Yards Width 2.8 Yards

4.5in Howitzer range 4,000 yards Charge 2 50% PEr Length 27.3 Yards Width 5.4 Yards

4.5in Howitzer range 4,000 yards Charge 3 50% PEr Length 38.3 Yards Width 6.3 Yards

4.5in Howitzer range 4,000 yards Charge 4 50% PEr Length 45.2 Yards Width 5.1 Yards

4.5in Howitzer range 4,000 yards Charge 5 50% PEr Length 51.5 Yards Width 15.8 Yards

PE Zone for 1 Gun firing Charge 1 is 93.2 yards x 11.2 yards

PE Zone for 1 Gun firing Charge 2 is 109.2 yards x 21.6 yards

PE Zone for 1 Gun firing Charge 3 is 152.2 yards x 25.2 yards

PE Zone for 1 Gun firing Charge 4 is 180.8 yards x 20.4 yards

PE Zone for 1 Gun firing Charge 1 is 257.5 yards x 63.2 yards

If the Gun Battery 4.5in Howitzers were deployed in a straight line gun position with the guns 30 yards apart the rounds would fall in box of these dimensions:-

Charge 1 93.2 Depth x 161,2 Wide

Charge 2 109.2 Depth x 171.6 Wide

Charge 3 152.2 Depth x 175.2 Wide

Charge 4 180.8 Depth x 170.4 Wide

Charge 5 257.5 Depth x 213.2 Wide

I have also read that Rolling Barrages would be fire on by guns up to the 2nd quarter of life or recently calibrated.

John

If a gun fired 100 rounds at the same Line and Elevation the rounds would falls thus.

[Chris Henschke]

Thank you,

that is exactly what I needed.

cheers,

Chris Henschke

[nigelfe]

GHQ Artillery Notes No 1, Close Shooting in the Field - Notes for Infantry Officers, Jan 1916, new edn Mar 1917, went ito the matter in some depth and explained what to do if own troops were closer that half the 100% zone. However, they also explained the importance of non-standard conditions, but did not dwell on ammo variability!

While a battery normally fired with lines of fire parallel, the option of 'sweep' and 'search' existed. However, in WW1 it doesn't seem to have been the practice to apply position corrections if the line of fire was significantly different to the zero line (ie to bring the mpi of each gun back into a roughly straight line at right angles to the line of fire).

[Pete1052]

However, in WW1 it doesn't seem to have been the practice to apply position corrections if the line of fire was significantly different to the zero line (ie to bring the mpi of each gun back into a roughly straight line at right angles to the line of fire).

Nigel, would a battery have registered prior to important missions in order to determine position corrections?

I've misplaced a U.S. Army reference book from the 1920s that described the direction of a battery's fire from a command observation post. From what I could tell the officer at the observation post, probably using a scope of some kind, was working out gunnery solutions in his head or on a pad of paper and having them telephoned to the battery. The book contained some firing table data that was recognizable to me, so I'm inclined to think something similar to a fire direction center was sometimes used for indirect fire back then, especially when observed fire wasn't possible. I've read that the meteorological plus velocity error technique was developed during the Great War, but in the absence of position corrections the technique would have been more helpful for determining range corrections rather than those for deflection (line).

[johnreed]

From 4.5in Howitzer Range Table the Table in Variations take into account the following for all charges:-

100 f.s decrease in MV a plus correction for range., Increase in Atmospheric Pressue of 1 inch an add correction in range, an increase of Air Temperature a minus correction in range Increase in Charge Temperature of 10 deg F a minus correction for range, Wind corection either head wind an add correction or tail wind a minus correction, a cross wind from the right a more in a line correction or a cross wind from the left which will be a less in aline correction.

There is also a correction for what type of fuze is fired this is dated 24th May 1918.

John

[nigelfe]

Nigel, would a battery have registered prior to important missions in order to determine position corrections?

I've misplaced a U.S. Army reference book from the 1920s that described the direction of a battery's fire from a command observation post. From what I could tell the officer at the observation post, probably using a scope of some kind, was working out gunnery solutions in his head or on a pad of paper and having them telephoned to the battery. The book contained some firing table data that was recognizable to me, so I'm inclined to think something similar to a fire direction center was sometimes used for indirect fire back then, especially when observed fire wasn't possible. I've read that the meteorological plus velocity error technique was developed during the Great War, but in the absence of position corrections the technique would have been more helpful for determining range corrections rather than those for deflection (line).

For an impromptu target they would have ranged and fired with lines of fire parallel, and not normally bothered about correcting individual guns. If it was a troops in open type of target, eg a wiring party or something, they would have almost certainly have used shrapnel, which typically had an effective bullet spread of about 300 yards along the line of fire. They probably wouldn't have bother about corrections for non standard conditions in these circumstances, but each gun would have applied its gun correction to compensate for its difference from standard MV. Of course 4.5 H was a bit more complicated because it was multi-charge but its range scale was for chg 4 (IIRC) so other charges required a false range as well.

My understanding is that the US didn't adopt FDCs until the early 1930s, copying the idea from the French. UK never called them that. For impromptu shoots the observer could well have produced the range and switch from the zero line and changed these during the ranging process, and no plotting or anything, he visualised the line of fire on the ground and ordered corrections accordingly.

Of course he may had ranged the centre point (on the zero line) of his zone which would obviously be a big help, particularly if it was a datum point as well. This was normal UK practice. However, if it was a zone call from an aircraft or a depth target then it would have been calculated on the battery position, all too often by the BC, taking range and switch from the artillery board/fighting map. However, registered targets would have had their data prepared and for some of them it would have been kept up to date with corrections for non-standard conditions, at least in the second half of the war when met messages were being issued 6 or 7 times per day.

Registration in the modern sense was called a datum point shoot and was used, so were witness points. Registration meant 'adjustment for future engagement' in modern terms.

[mark parker]

Unfortunately, the only reference I have for the 18 pdr is the 1915 handbook.

I have searched the forum but can't find anything specifically to answer my question.

I understand the concept of the 50% zone but what would be the beaten zone for 18 pdr and 4.5" How batteries (6 gun batteries) at about 4000 yards, firing over level terrain?

For point targets and area targets? Does a battery converge?

(disregarding variables : wind, temperature, barrel wear, etc.)

Chris Henschke

Chris, this doesn't answer your question specifically because it doesn't indicate who was shooting at what exactly, but might be interesting, it shows distance and would indicate that they could quite accurately land shells on the barrage lines. Its a map from a book of my Grandfather's, who was in the field artillery 7th FAB, showing artillery positions, gun types and creeping barrage lines as per time of advance, the guns being used in this sector are listed on the left if the resolution is good enough to enlarge and read?

[nigelfe]

Chris, this doesn't answer your question specifically because it doesn't indicate who was shooting at what exactly, but might be interesting, it shows distance and would indicate that they could quite accurately land shells on the barrage lines. Its a map from a book of my Grandfather's, who was in the field artillery 7th FAB, showing artillery positions, gun types and creeping barrage lines as per time of advance, the guns being used in this sector are listed on the left if the resolution is good enough to enlarge and read?

Actually they were aiming at the barrage lines, which is not quite the same thing as hitting them. Furthermore they were almost certainly engaging several lines simultanously and creeping forward one line at a time. The 18-prs were probably engaging the 2 lines nearest own troops, possibly with the next line or 2 engaged by 6-in H. The 18-prs were probably firing shrapnel. Of course the aim was not to drop shells on the line (which shrapnel doesn't do in any case), it was to put the mpi along the lines allowing the zone of the guns to put rounds in the gaps between the lines.

[mark parker]

Actually they were aiming at the barrage lines, which is not quite the same thing as hitting them. Furthermore they were almost certainly engaging several lines simultanously and creeping forward one line at a time. The 18-prs were probably engaging the 2 lines nearest own troops, possibly with the next line or 2 engaged by 6-in H. The 18-prs were probably firing shrapnel. Of course the aim was not to drop shells on the line (which shrapnel doesn't do in any case), it was to put the mpi along the lines allowing the zone of the guns to put rounds in the gaps between the lines.

That's interesting and it looks like that where its marked 'protective barrage' which would include the four lines out from the objective line. From what I've read they also fired coloured smoke, so defenders would don gasmasks which further hamper them somewhat.

This is probably a very good example of well organized effective artillery use in WW1. mpi?

[Pete1052]

When I was a junior second lieutenant in West Germany in January '79 I saw our partnership Bundeswehr artillery battalion using a command observation post arrangement during a field exercise at Munster Lager. The battalion commander and his operations officer and staff, as well as a coffee urn, pastries, and a portable heater, were up in a three-story observation tower with a hut on top a bit like those used by forest rangers in the U.S. in the '40s-'50s to spot forest fires. The three battery commanders were in foxholes about 50 meters forward of the tower and about 20 meters apart observing the fire of their batteries. The Bundeswehr had FDCs at the time so I don't think the battery commanders were doing gunnery solutions. The main point of the arrangement seemed to be that the battalion commander could have one of his batteries conduct a fire mission and then have the responsible battery commander climb up into the tower to have his **** chewed. You could tell how fouled up the fire mission had been by the number of times the Hauptman came to the position of attention and said to the colonel, 'Jawohl, alles klar." It was a strange experience for me, there was snow on the ground and I couldn't help but think about the Russian front or the Bulge in '44.

[nigelfe]

That's interesting and it looks like that where its marked 'protective barrage' which would include the four lines out from the objective line. From what I've read they also fired coloured smoke, so defenders would don gasmasks which further hamper them somewhat.

This is probably a very good example of well organized effective artillery use in WW1. mpi?

The protective or standing barrage was to protect the troops on the final objective from counter attack. Obviously the covering fire (creeping) barrage (ie most of it) would extend a bit beyond the objective itself.

As far I know there was was no coloured smoke in WW1, however, white screening smoke had been introduced a year or so before 1918.

This type of barrage was standard practice for the period. The barrage would have been divided up into lanes running through it at right angles to the lines with a lane assigned to an artillery unit.

Of course there's a lot that the map doesn't show, most notably all the counter-battery targets. Gas would have been used on these as well as HE. The super heavy artillery listed would have been engaging targets in greater depth.

[nigelfe]

When I was a junior second lieutenant in West Germany in January '79 I saw our partnership Bundeswehr artillery battalion using a command observation post arrangement during a field exercise at Munster Lager. The battalion commander and his operations officer and staff, as well as a coffee urn, pastries, and a portable heater, were up in a three-story observation tower with a hut on top a bit like those used by forest rangers in the U.S. in the '40s-'50s to spot forest fires. The three battery commanders were in foxholes about 50 meters forward of the tower and about 20 meters apart observing the fire of their batteries. The Bundeswehr had FDCs at the time so I don't think the battery commanders were doing gunnery solutions. The main point of the arrangement seemed to be that the battalion commander could have one of his batteries conduct a fire mission and then have the responsible battery commander climb up into the tower to have his **** chewed. You could tell how fouled up the fire mission had been by the number of times the Hauptman came to the position of attention and said to the colonel, 'Jawohl, alles klar." It was a strange experience for me, there was snow on the ground and I couldn't help but think about the Russian front or the Bulge in '44.

Like UK post WW2 the Bundeswehr leaves all technical fire control to the gun end, forward observers are responsible for technical fire control only. Obviously the deployment of observers on artillery ranges for live firing bears very little relation to tactical reality.