Anti aircraft Stokes Mortar

[centurion]

In his book Mortars, Ian Hogg has a photo of a Stokes Mortar fitted with an anti aircraft sight. He professes not to know the origin of this but expresses doubts as to its possible effectiveness.

I had thought I had discovered the background when I found the following in an Australian technical history

Not all technical and tactical ideas were winners. Lieutenant F Brand of the 7th Light Trench Mortar Battery conducted experiments in the use of the Stokes Mortar as an anti aircraft weapon in November 1917. The Stokes was fired with a barrel and base plate only, the number one positioning the portar by hand using a sight he improvised. I Anzac Corps School carried out further tests. The general impression of this innovation was summed up by Brigadier General Charles Rosenthal who felt that the lack of a reliable fuze, the variations of range and the slowness of the bomb relative to an aircraft it was most unlikely that an enemy aircraft could ever be brought down by a Stokes Mortar

However the description given is at varience with the photo in Hogg's book which shows a Stokes with the full tripod and a very elaborate sight which could not have been used by the no 1 pointing the barrel by hand (unless he had a prehensile neck). Was there more than one attempt to devise an AA Stokes? Was this a purely Australian endeavour?

[Chris Henschke]

Was there more than one attempt to devise an AA Stokes? Was this a purely Australian endeavour?

"The British and Canadians continued to search for more effective ways of defending themselves against enemy aircraft. following the German lead, the First Army discussed the possibility of using three-inch Stokes mortars against airplanes, and in May 1918 the 2nd Division carried out experiments to determine the mortar's effectiveness against low-flying aircraft..."

Surviving Trench Warfare, Technology and the Canadian Corps, 1914-1918. Bill Rawling.

The Mallet thesis [from which you quote] doesn't mention the Canadian involvement and Rawling's book doesn't mention the Brand experiments of November, 1917. It would be interesting to find out what was meant by 'the German lead.'

Chris Henschke

[centurion]

Is it possible that the "German lead" refers to the German use of trench mortars in other roles? Revised carriages had been devised by the Germans in 1917 to allow their mortars to fire on a flatter trajectory and be used as anti tank weapons with some success. Possibly the lead refers to being more inventive in the use of mortars rather than a spedific AA role.

[Dolphin]

There's a report of German trials of trench mortars as anti-aircraft weapons in Peter Barton's Passchendaele. At some time prior to 31 July 1917 the German 1st Guard Reserve Division and 4th Guards Division tried using the light Minenwerfer in an AA role. Fuses were set for 7 seconds, and the aiming point was 200-500 metres ahead of the aeroplane. The shells should have detonated between 200 and 600 metres above ground.

It looks like several minds (on both sides of the lines) thought alike.

Gareth

[chris mccarthy]

Surviving Trench Warfare takes on a whole new meaning! I would imagine it was bad enough with German mortars raining down.....

[Old Tom]

Hello,

I think Brigadier General Charles Rosenthal summed it up very well.

Old Tom

[montbrehain]

reminds me of a tale from Joe Maxwell VC book called "Hells Bells and Madamoiselles" Every morning a Jerry Pilot would fly down low and strafe the Aussie lines. A Irishman in the trench (serving in the AIF) got fed up with it and so one morning lay in wait for the pilot. he lay on his back on the trench floor with a rifle loaded with a rifle grenade. as the plane swooped down he let fire ....... missed of course ! and then all his mates had to run like heck when the grenade came straight back down. they were not impressed HAHA "MO"

[Joe Sweeney]

The use of Stokes Mortars in an AA role is captured in one of the British armies SS Documents on Mortar training from 1918 (June ?).

I have a copy but I'm not home now and can't remember the SS number.

Special devises were also adapted to include sight and handles--none of which may have made it to the front prior to the Armistice. However, use as an AA weapon was not dependent upon these devices.

I actually had a similar question years ago on another forum and Mike H. (member of this forum) supplied the SS references from the IWM--which I immediately ordered as use of a Mortar as an AA weapon seems strange.

The genesis of my question is one of the Operations Orders in the officiaal history actual has the AA use of mortars mentioned and I actually believe it dated from Cambrai (not 100% certain and i can't check at the moment).

In no way a purely Australian endeavor.

Joe Sweeney

[centurion]

All very interesting, it shows how bad ideas can persist for in WW2 attempts were again made to use mortars for AA, however applying a slightly different approach to WW1. A number of experiments were carried out in Britain, Germany and Japan in using a number of mortars (sometimes multi barreled) to lay arial minefields in front of incoming flights of bombers, these consisted of bomblets dangling on long wires from slowly descending parachutes (the Japanese were actually looking at having a mortar fitted in bombers to lay down a similar defence in front of fighters attacking from the rear) neverthes less the practicality of all these schemes proved on a par with the Stokes AA of 1917/18

[jhill]

It seems that at this time (late 1917), the controversy over air policy was coming to a head. In the Ypres sector, the Germans had begun a substantial effort to attack ground targets from the air, both on and behind the battle field. At the same time, the "Trenchard doctrine" required that British aircraft were usually far behind the German lines, attacking airfields and whatnot. The Infantry, in particular, complained loudly that they were continually suffering casualties from German aircraft, with nary a British machine in the sky.

This might have prompted the following mention in The Canadian Corps Instructions for the Offensive - Passchendaele No. 1. of 23rd October, 1917:

"...

Anti-Aircraft Defence.

...

It must be clearly understood that the duty of defending themselves against low flying aircraft rests with the Infantry. Our own aeroplanes cannot effectively deal with them but recent experience on this front has conclusively proved that rifle and machine gun fire from the ground is most effective for the purpose.

..."

Lower formations seem to have been left to try out schemes on their own. In the Addenda to Instructions for the Offensive, No. 1. of 4th November, 1917, the commander of the 1st Canadian Infantry Brigade, Brig. Gen. W.A. Griesbach, decreed the following:

"...

11. Battalion Commanders will experiment and report whether they consider it would be practical to use rifle grenades against hostile aeroplanes. If the report is favourable, troops will be instructed accordingly."

Historians or the air war can no doubt fill us in on the ins and outs of the Trenchard doctrine over time.

[Dolphin]

Historians of the air war can no doubt fill us in on the ins and outs of the Trenchard doctrine over time.

In essence, the Trenchard doctrine was that the RFC should be on the offensive at all times. This was seen as an aeronautical interpretation of the Naval dictum of "making the enemy's coast our frontier". In theory, the RFC would to attack the enemy well behind German lines, so that the sky over No Man's Land was RFC territory. In practice, it meant that the men of the RFC were frequently sent out in inadequate aeroplanes in an effort to dominate the skies over the German side of the lines by conducting and escorting long reconnaissance and bombing missions.

In contrast, the Germans were generally more content to defend their airspace, and to limit daylight operations on the Allied side of the lines to specialist high altitude reconnaissance and occasional "balloon-busting" sorties. At the same time, the Germans put great emphasis on the development of speciualist infantry support aeroplanes.

I hope that this helps.

Gareth

[centurion]

In addition its worth looking at the German 'Battle' flights, originally made up of CL type two seaters. These had the task of conducting offensive operations (ahead of the German infantry) in support of attacks and counter attacks (but also used defensively to hit the communications etc of attacking forces - for example bridges). They proved themselves in the German counter attack at first Cambrai. In German Aircraft of the First World War Peter Grey and Owen Thetford include a 7 page translation of the official German detailed orders for Battle Flights issued in Feb 1918. A bit long to include here but it is worth repeating section III/9 Employment of Battle Flights - Attack

"In the attack the battle flights will be employed in force to destroy the enemy's forward infantry lines and harass his barrage batteries. In the battle flights the Higer Command posses a powerful weapon which should be employed at tge DECISIVE point of the attack. They are not to be distributed singly over the whole front of attack, but should be cncentrated at decisive points. Less important sectors must dispense with the support of battle flights"

If read in conjunction with section I/3 which reads

"Formations of reconnaisance flights should not be employed for the attack of ground targets as this would be to the detriment of their special work of recce and observation. On the other hand; the contact patrol machine, which from the very nature of its duties, is compelled to fly low, will frequently find opportunities to employ its machine gun against ground targets.

Bombing Squadrons are not suitable for low flying work..

The most important role of pursuit flights is the engagement of the enemy's air forces."

This suggests that the aircraft making the sustained attacks described in an earlier posting to the thread were battle flights. These aircraft were effectively two seater fighter/bombers, fast and flying low therefore difficult to detect and therefor intercept before they their targets. The attacked infantry see only the irraft attacking them they do not see any shot down before or after the attack by defending planes. "Where was our air force ?"is acry frequently made by soldiers of all sides in both world wars.

[Chris Henschke]

The use of Stokes Mortars in an AA role is captured in one of the British armies SS Documents on Mortar training from 1918 (June ?).

I have a copy but I'm not home now and can't remember the SS number.

Special devises were also adapted to include sight and handles--none of which may have made it to the front prior to the Armistice. However, use as an AA weapon was not dependent upon these devices.

I actually had a similar question years ago on another forum and Mike H. (member of this forum) supplied the SS references from the IWM--which I immediately ordered as use of a Mortar as an AA weapon seems strange.

The genesis of my question is one of the Operations Orders in the officiaal history actual has the AA use of mortars mentioned and I actually believe it dated from Cambrai (not 100% certain and i can't check at the moment).

In no way a purely Australian endeavor.

Joe Sweeney

SS 189 Light Mortar Training, June 1918. covers this aspect. Chapter XI, Anti-Aircraft. Barrage Lines and Aimed Fire against Aircraft.

' A design of a light mortar sight suitable for anti-aircraft work has been approved. It consists of two mirrors set at an angle of 150 degrees mounted on a wooden block, which can be placed on a sight bracket.

The front half of the mirror is used in conjunction with the forward aperture sight for the attack of aircraft approaching at an angle or for crossing shots; the back half of the mirror is used in conjunction with the back aperture sight for aeroplanes going away in any direction...'

Chris Henschke

[2ndCMR]

During our two months of trench warfare following the battle of Messines we experimented with the Stokes for anti-aircraft defence, and found it most successful. In this branch we—(at that time I was in the 4th Light Trench Mortar Battalion)—were the first battery to try this exciting means of stopping Hun aircraft from flying over our trenches.

I remember the first day we tried the Stokes out in its new capacity, how excited we all were at the possibility of bringing down an enemy 'plane. We set up three guns at intervals of about 150 yards along the front: one gun with fuses cut to burst at three seconds, another at four seconds, and another at five seconds; and patiently awaited developments. It was not long before our patience was rewarded, and a big enemy plane crossed our line at a height of about 500 feet. The nearest gun opened on him with two fine bursts just above him, while simultaneously the second gun put two equally good bursts underneath. The Infantry were very interested and excited at the thought of the possibility of bringing down a 'plane, and the machine seemed to falter and fall and then right itself and made off back to the enemy lines. Other enemy planes came over that day to investigate this new method of ours in anti-aircraft defence, but were very wary, and kept at a height where our mortars could not reach them.

In effect, the result obtained was this: that our lines were very seldom crossed by low-flying enemy 'planes in this sector.

A few nights later our Battery was relieved from the line, and we in the Trench Mortars were billetted at that time in Nieppe, near the Square. About 11 p.m. a number of Gothas came over on a bombing raid and hovered over the town. Our senior sergeant, who was always on for any stunt where the mortars were concerned, dashed up to my room and asked permission to have a "go" at the intruders, which permission was readily given. In a minute or two we had two guns out and were blazing away in great style at four of the enemy 'planes, which soon rose to a great height and left the village; and they deposited their loads of "eggs," as we called their bombs, a few minutes later in our Artillery horse lines at Croix du Bac, killing about 80 horses, and made off for home.

http://209.85.173.132/search?q=cache:3rR3i...;cd=6&gl=ca

[pjjobson]

This may shed a little light on the question, it is a direct quote from a book entitled "With the NZ Trench Mortars in France" by Capt W E L Napier MC.

"During our two months of trench warfare following the battle of Messines we experimented with the Stokes for anti-aircraft defence, and found it most successful. In this branch we—(at that time I was in the 4th Light Trench Mortar Battalion)—were the first battery to try this exciting means of stopping Hun aircraft from flying over our trenches.

I remember the first day we tried the Stokes out in its new capacity, how excited we all were at the possibility of bringing down an enemy 'plane. We set up three guns at intervals of about 150 yards along the front: one gun with fuses cut to burst at three seconds, another at four seconds, and another at five seconds; and patiently awaited developments. It was not long before our patience was rewarded, and a big enemy plane crossed our line at a height of about 500 feet. The nearest gun opened on him with two fine bursts just above him, while simultaneously the second gun put two equally good bursts underneath. The Infantry were very interested and excited at the thought of the possibility of bringing down a 'plane, and the machine seemed to falter and fall and then right itself and made off back to the enemy lines. Other enemy planes came over that day to investigate this new method of ours in anti-aircraft defence, but were very wary, and kept at a height where our mortars could not reach them.

In effect, the result obtained was this: that our lines were very seldom crossed by low-flying enemy 'planes in this sector.

A few nights later our Battery was relieved from the line, and we in the Trench Mortars were billetted at that time in Nieppe, near the Square. About 11 p.m. a number of Gothas came over on a bombing raid and hovered over the town. Our senior sergeant, who was always on for any stunt where the mortars were concerned, dashed up to my room and asked permission to have a "go" at the intruders, which permission was readily given. In a minute or two we had two guns out and were blazing away in great style at four of the enemy 'planes, which soon rose to a great height and left the village; and they deposited their loads of "eggs," as we called their bombs, a few minutes later in our Artillery horse lines at Croix du Bac, killing about 80 horses, and made off for home.

The sequel to this night firing at the 'planes from Nieppe was a curt "chit" from Brigade Headquarters the following morning prohibiting firing from towns at enemy aircraft. The reason for this we found out afterwards was that a number of pieces of shell had dropped on our Brigadier's chateau, which, of course, we were very sorry for, but fortunately nobody was injured."

Incidentally this book is available to read on the web at http://www.nzetc.org/tm/scholarly/tei-WH1-Tren.html

Regards

Phil

[bushfighter]

The theory works, as a planeload of Belgian paratroopers found out to their fatal cost in northern Germany 30 or 40 years ago.

The mortar was a British 81mm.

[charlie962]

Just adding this little snippet that suprised me but glad to find this excellent old discussion that answers the question I was about to pose.

 

Extract of Fourth Army AntiAircraft Group War Diary Dec 1917 (WO95-483-3)

 

Instructions for Anti-Aircraft Defence  (Second Army 57(G) App B  14/12/17)

 

12. In addition to Lewis and machine guns, the possibility of using Stokes mortars for anti-aircraft defence should not be overlooked. Stokes mortars have already been employed in some places apparently with success, and the Germans have been using their mortars for a similar purpose. The use of this weapon against low-flying aeroplanes involves certain risks but may have possibilities. Experiments should be carried out to ascertain the best means of employing them for anti-aircraft work.

 

Charlie

[Skipman]

Am looking at the 39th Division war diary November 1917 and in the weekly Intelligence Summaries there are any amount of mentions of Stokes Mortars being used against enemy aircraft. For example, on the 11th November, 1917 "Stokes Guns fired on Lewis House and Berry Cotts in reply to hostile Grenatenwerfer and engaged EA with special fuze."

Mike

 

[Gunner Bailey]

Must have been a timed fuze. Great find.

[Skipman]

Again from the 39th Division Diary,  the Weekly Summary of Operations 8/11/1917-15/11/1917

Mike

 

[ianjonesncl]

Another thread by @Simon Birch relates to a premature explosion of a Stokes Mortar and details it was firing in an AA role when the accident occurred;

1 KRRC 27th Feb. 1918. - Soldiers and their units - Great War Forum

 

The British Ordnance Collectors Network shows a Stokes Mortar in the AA role;

3in stokes mortar anti aircraft (bocn.co.uk)

 

The last war dairy entry by Mike shows that to have an effect the aircraft do not necessarily need to be destroyed, the fact the they turned away would disrupt their intended activity, hopefully preventing casulaties.  

[ServiceRumDiluted]

On 21/04/2021 at 09:22, Gunner Bailey said:

Must have been a timed fuze. Great find.

 

Does anyone know what fuze this would be? I'd guess either the Mills type pistol with the delay cut down, which seems a bit time consuming for AA work, or more likely the 28 Sutton Fuze.

[Skipman]

1 hour ago, ServiceRumDiluted said:

 

Does anyone know what fuze this would be? I'd guess either the Mills type pistol with the delay cut down, which seems a bit time consuming for AA work, or more likely the 28 Sutton Fuze.

 

Just says "special fuze" might be worth a look on this site it mentions anti-aircraft fuzes but not Stokes  Click

 

Mike

[ServiceRumDiluted]

Thanks Skipman, I seem to be somehow developing quite an interest in Trench Mortars of WW1 and their fuzes.  As far as I know the Stokes was used with the Mills Pistol type which was not able to be set to a time other than by cutting short the slow burn wick, the 146 all-ways which was an impact fuze, and the 28 Sutton which was a basic time fuze with a lead pipe powder train pierced at the desired time interval. My guess is that it would be that used for AA work but I'd love either confirmation or another alternative.

[ianjonesncl]

2 hours ago, ServiceRumDiluted said:

 As far as I know the Stokes was used with the Mills Pistol type which was not able to be set to a time other than by cutting short the slow burn wick, the 146 all-ways which was an impact fuze, and the 28 Sutton which was a basic time fuze with a lead pipe powder train pierced at the desired time interval.

 

It looks like the Mills Pistol type and possibly a 28 Sutton may both have been used.

 

The post from Phil Jobson @pjjobson sounds like the methodology of cutting a fuze; [Just after Messines so July / August 1917 ?] 

On 03/12/2008 at 10:12, pjjobson said:

We set up three guns at intervals of about 150 yards along the front: one gun with fuses cut to burst at three seconds, another at four seconds, and another at five seconds; and patiently awaited developments.

 

whilst the post from Mike @Skipman of a "special fuze" [ November 1917] may indicate a time fuze possibly the 28 Sutton.