32nd Division. No. S.G. 163.
32nd Div. Arty. No.G.869.
14th Inf. Bde. S.O.104.
R.A. 1 Corps
No.496 (G.a.) 21st July 1916.
The attached notes are the results of enquiries which have been made as to the working of Signal communications during the recent fighting, and are forwarded for your information.
In view of the fact that visual signalling has been so successfully used, all signallers, Artillery as well as Infantry, should be frequently practiced in this method of communication.
(Sd) J.K. DICK, CUNYNGHAM, Lt. Col., G.S.
For Brigadier General, General Staff, 1 Corps.
COMMUNICATIONS DURING THE OFFENSIVE OF JULY 1916.
- The means of communication that have been used in addition to the ordinary telegraph and telephone system are:-
- VISUAL, including signalling to aeroplanes and balloons.
- Observation by contact aeroplanes.
- Earth currents. Runners have been considered as the normal means of communication within a battalion and also for carrying secret messages, such as operation orders, between brigades and battalions.
- All except the last have met with a certain measure of success, but visual has been proved by far the most useful, due chiefly to the nature of the country in which these operations are being carried on.
- TELEGRAPH AND TELEPHONE SYSTEM.
- IN THE PREPARATORY stages of operations a system of main routes for telegraph and telephone circuits was laid out, both at right angles and parallel to the front. In areas not liable to heavy shelling these routes were of overhead lines; forward of this they consisted of cables buried 6 feet deep. Just prior to the commencement of operations, some of these buried routes were extended to the front line and tunnels constructed as far towards the enemy’s line as possible. The buried routes proved a great success. This was partly due to the absence of enemy artillery fire behind our lines. Only one case of a buried route being cut was reported; 24 hours were necessary to complete repairs. At first, this appears imprudent owing to the length of time taken to repair buried routes when cut by a shell, but in reality it is more satisfactory to run a new alternative line overground when required, than to attempt to keep one up through heavy bombardment.
- In some cases, no direct wires from batteries to O.P.’s were laid, but the O.P. Exchange System was enlarged, and batteries was plugged through to their O.P.s for definite periods on the orders of the Group Commander.
- Many lines, even such as Battery O.P. were not duplicated by cable overground, but for all important lines there were alternative ways of “getting through” in the underground system.
- The frequent moves of divisions has shewn that these routes should be on a most liberal scale and not planned merely to meet the requirements at the time of construction.
- On the commencement of the offensive. – lines carried forward by battalions with one of the waves of the attack never lasted long enough to be of value. On the first cessation of the barrage, Brigade Sections with the aid of the Battalion Signallers, left behind for the purpose, laid D.5 cable forward. Only in a few cases was difficulty experienced in keeping the wires through. At the same time the tunnels under the neutral zone were broken into and completed as trenches into the enemy’s line. As the advance progressed and Brigades moved across the old trench line, trouble began to be experienced with lines from Divisions to Brigades, chiefly owing to damage to cables by traffic. At this stage Corps could render assistance by building at least one airline forward for each of its Divisions. These would be of value to the Corps later on, when the Divisions advance. Most Divisions gave up sounders and reverted to buzzers for telegraphic purposes on account of the leakage on lines. Fuller-phones were tried, but in most cases unsuccessfully. This was chiefly due to lack of experience in their use, as they had been issued so short a time beforehand.
- Owing to the congestion of traffic, much time can be saved by establishing forward dumps of cable and line stores beforehand, and arranging that parties employed on construction shall billet or bivouac near their work.
- For crossing the neutral zone, Twin cable armoured with galvanised iron wire, was tried, but the extra durability was far outweighed by the difficulty of repair.
- VISUAL. Visual has been almost universally successful. This is partly due to the fact that the country is admirably adapted to this means of communication. Every type of visual signalling, except Helio and Rockets was used, but the one that was most satisfactory was the “Projector Protatif” (or “French Lamp”) which, whilst lighter and less cumbersome than shutters or aeroplane lamps is suitable both for day and night work and for signalling to aeroplanes and balloons. Discs of about ten inch diameter, on sticks 2 feet long, were used and found very portable, but their range is limited to approximately 1 ¼ miles. Shutters were also used with success, but 50 per cent of them always seem to be discarded in the advance. In many cases batteries after they advanced, used visual to their F.O.O.S and vice versa.
- Divisions installed one or more receiving stations to cover the whole of their front. In cases, acknowledgements of messages were given by a semaphore arm (or lamps at night) 100 yards away from the actual station.
- The apparatus consists of an electric bulb and reflector in a thin metal case about a foot in diameter, and batteries carried in pouches on a belt. It is light enough to hold in the hand whilst signalling and the dispersion is such that no more rigid base is necessary. By day, except in bright sunlight, it can be read at 4,000 yards. By night, red shades have been used to prevent the ray drawing fire.
- CONTACT AEROPLANES. Observers usually succeeded in following the progress of the battle without aid from the infantry. In some cases groups of 5 flares were lit by the latter at stated hours, but a better method would appear to be for the observer to call for this signal when he is in doubt as to the position of our troops, by dropping a flare from the aeroplane. In some Corps different Brigades used different coloured flares; in others all used one colour which was changed daily to minimise the risk of the enemy copying the signal. On occasions the lighting of flares drew fire. The carrying of mirrors by the infantry is an assistance to the observer but can be easily initiated by the enemy and is further liable to give false information when men are taken prisoner.Signalling to aeroplanes was not a success. Only a few messages were sent by the Infantry and many of these were not read. This system requires much practice to be of real utility. Its failure may be attributed to two causes – firstly that ordinary visualling was almost always possible, and, very naturally, the Infantry used the means to which they were most accustomed: Secondly, that the infantry were given too many means of communication and did not trouble to carry the ground signalling sheets very far. R.F.C. lamps are altogether too heavy for use during an advance.
- Information acquired was disposed of, either by dropping messages at Divisional Headquarters or by wireless to special Wireless Stations at Divisional Headquarters. In one case Corps Headquarters had a Wireless Station which also received these messages, but this necessitated the aeroplane coming back a short distance to get within range.
- The ground signals for identifying Headquarters were found useful.
- BALLOONS. Signalling to balloons was in general a failure due to the distance they were off, the difficulty of distinguishing the correct balloon, the difficulties of the observer reading the message when the balloon is swinging. The observer in the balloon disposed of the message by telegraphing it to his telephonist on the ground, as he received it. The difficulty of using balloons may have been due to lack of practice on both sides, but it is a system not worth perfecting in a country suited to visual. In flat country it might of great use for night work, but for day work, balloons are usually to far back.
- One Battalion appears to have sent an important message back by this means which reached its address in 8 minutes.
- A system of identification was arranged. By day, pennants were carried but they were not distinguishable unless the wind was parallel to the front. By night, distinguishing signals were sent by lamp at regular intervals, successions of dots, dashes, dots and dashes, or an open light being used for any 4 adjacent balloons.
- Pigeons. Pigeons proved very successful in most cases, even through a heavy barrage. A small proportion were very slow in coming in. Some of these failures are no doubt attributable to lack of care taken of the birds after their distribution due chiefly to the insufficient number of trained men available.
- In a country unsuited to visual, the number of pigeons used might well be increased to a daily supply of 8 per Battalion. This would mean a very large increase in the number of men to be trained. It would also be an advantage for one officer per battalion to receive a little elementary instruction in the care of the birds.
- Wireless. Wireless was generally found to be little used owing to visual being so easily worked. On one occasion, however, as “SCOTS REDOUBT” it saved the situation when the troops at this point were cut off. In one Division it was stated that wireless communication was rarely established. This may be due to the fact that trench sets vary in efficiency; some are always giving trouble. On the right of our line, wireless could not be satisfactorily worked owing to “jamming” caused by the French aeroplanes sending out un-tuned signals.The system generally adopted is to install one trench set per Division, keeping the other ready packed up, and ready for an advance. As soon as this second set is installed and working, the former is brought up and kept in hand till required by a further advance, or occasionally it may be sent off temporarily with any unit of the Division that is likely to get out of touch.The Corps Wireless Officer controls the working of the Trench Sets, although the Divisional Signal Officer give the orders as to when and where they are to move. The Trench Sets are usually placed with Brigade Headquarters, but in exceptional circumstances may be with a Battalion.Each Corps works on one wave length.
- No ground aerials were used.
- Whilst the Corps Wireless set is being moved up, the two sets of each Division can work to each other, or else a set can be temporarily withdrawn from one of the Divisions to take the place of the Corps Set whilst it is being moved.
- The Trench Sets always work back to the Corps Station which is pushed forward as far as possible with safety.
- No one will use wireless when other means are available, on account of the necessity of coding. Many commanders found difficulty in expressing themselves in the sentences of the code book. This is due, chiefly, to lack of practice. In one Corps, an officer (not a Signal Officer) was attached to each wireless set to code messages, lists of sentences only being issued to Battalion Commanders.
- Earth Currants. The apparatus for this consists of a special buzzer for the forward station and a valve amplifier for the back station. The first sets were only issued a few days before operations commenced, and can hardly be said to have had a fair trial.The range is small, about 2,000 yards; the back station, which contains delicate apparatus, has therefore to be far forward and keep moving up as the advance continues.
- This method of communication is more suited to short advances where the back station can remain in a dug-out in our trenches.
- In every case the back station either failed to pick up the signals, or it could not reach them amongst the noise caused by the leakage from the cable circuits in the vicinity.