Advance Report of B.C.F. Gunnery Committee

Advance Report of Gunnery Committee in the Battle Cruiser Fleet formed on the orders of Vice-Admiral Sir David Beatty after the Battle of Jutland. There is a copy at the National Maritime Museum, London, in Beatty's private papers, which is reproduced in a volume of Beatty's letters published by the Navy Records Society. There is also at least one copy at The National Archives, Kew.

Report

"Lion"

22nd June 1916

SIR,

We have the honour to forward an advance report of the Gunnery Committee formed by your orders to consider the lessons learnt on May 31st 1916.

Rear-Admiral Brock and Commander Egerton have been absent from the meetings on leave, but in view of the importance of certain lessons being promulgated without delay, we have not waited for their return before issuing the immediate report.

A further and more thorough report will be sent in later.

We have the honour to be,

Sir,

Your obedient Servants,

(Signed) A. E. CHATFIELD Captain, H.M.S. "Lion"

(Signed) E. R. RUSHTON Acting Captain, H.M.S. "Southampton"

(Signed) S. R. BAILEY Commander (G)

The Vice Admiral Commanding Battle Cruiser Fleet

Gunnery Lessons learnt from Action of 31st May

Having reviewed the reports of all ships of the B.C.F. and 5th B.S., the Committee consider that from a Gunnery stand point three main features stand out as requiring immediate consideration and action in view of a possible early meeting with the enemy. Should the recommendations meet with your approval either wholly or in part, they are such as can be immediately put into operation without delay, and it is with this idea in mind that they have been framed.

2. The Committee accordingly have dealt with these more urgent questions in this advanced report in order to meet the immediate necessities of the B.C.F. and 5th B.S. Their intention is to forward a further report on the many other points of value and interest which have arisen.

3. Under the weather and light conditions of the recent action the British system of fire control was put to the severest test imaginable, and on the whole it may be said to have stood the test successfully in that it proved our ability to inflict heavy damage on the enemy even under conditions most difficult for us and most favourable to him. At the same time these conditions have shown weak points with which we propose to deal.

4. The three outstanding features are:-

(a) The necessity of rapid and early hitting.

(b) The use of defensive tactics to avoid being hit.

(c) The safety of magazines and ammunition.

5. (a) THE NECESSITY OF RAPID AND EARLY HITTING

(i) Rapid ranging

At the commencement of the recent action it is known that the fourth salvo from an enemy ship was fired after 1 1/2 minutes, while the fourth salvo from our ship was fired at 4 minutes. This shows that the enemy have a system of ranging by a succession of rapid salvos.

There are undoubtedly great advantages in this method as compared with that of waiting for the fall of shot before firing the next salvo.

While, therefore, there is no great difference in accuracy in their opening range as compared with ours, they have, undoubtedly, greater chances of first hitting. We therefore recommend that this form of attack should be countered by a 'ladder' system of salvoes - the general idea of which is as given below, and it is meanwhile being further investigated on the spotting table.

We are strongly of opinion that though the ladder system appears, on first sight, to be extravagant of ammunition, this is not the case; on the contrary the present system has shown itself to be so when the enemy is zigzagging.

Firstly, because the rate of spotting is not sufficiently quick to give the necessary indication as to change of enemy's course.

Secondly, because the universal experience in the B.C.F. and 5th B.S. was that a correct rate was only achieved at considerable intervals for short periods.

(ii) Ladder system of finding or re-finding the target

On opening fire. Range, deflection, and rate to be calculated as at present, but 2 or 3 salvoes (according to the time of flight) to be fired in rapid succession without waiting to spot fall of shot.

Sights to be adjusted as follows:—

1st salvo: A determined amount below the estimated range.

2nd salvo: Mean or estimated range.

3rd salvo: A determined amount above the estimated range.

Should these combined salvoes not cross the target, repeat the ladder until the target is crossed.

It is not for a moment intended that the Control Officers' hands should be tied, in any way, by a hard and fast rule; according to circumstances it may be best to fire a three salvo ladder before spotting, or to fire two ladders of two salvoes each - much must depend on how soon the target is crossed. In considering this system it must be borne in mind that on several occasions on 31st May the enemy re-appeared from the mist and fire was immediately re-opened before a single rangefinder reading had been obtained. These conditions have now been experienced so frequently that they cannot be considered other than usual, and they must be catered for.

The Control Officer, using this system, would decide on the number of salvoes in the ladder and the size of the steps by the information received from the rangefinders, if any, in precisely the same way that he now is guided as to the size of the bracket. This ladder should be repeated until the target is crossed, (by which it will be known within what limits the range lies), then the ladder should be repeated with reduced steps until one salvo straddles the target. As soon as the straddle is obtained deliberate or rapid salvoes should be continued, as at present, until the target is entirely lost, and then we consider that the ladder system is the quickest way of regaining touch.

(iii) Rate finding and keeping.

From the difficulties experienced by Control Officers, and from the observation of Galatea and Yarmouth, the fact is established that the enemy altered course frequently, but on what system there is no evidence.

Generally speaking, the rate was in error, due to this, but during occasional intervals it was correct, and hitting was established for a short time.

The action, taken through all its phases, appears to show that more value was obtained from rangefinders by some ships than by others, and that at such times as the enemy was on a steady course undoubted assistance was received from the plot. It is again strongly emphasised that the enemy system of continuously altering course defeats any system of fire control based on rate-finding, for the reason that by the time the plot has established a rate it is no longer applicable.

It is considered that eventually a fully developed rangefinder system will give quicker information than any other, as to the movements of the enemy; i.e., an alteration of range will tend to be known in advance of firing rather than after the process of spotting has been resorted to.

A system by which the mean of the rangefinder readings is transmitted direct to the sights would cope with this, and every effort towards advance in such a direction is imperative. Whether this can be achieved with the existing service rangefinders is doubtful except under abnormally favourable conditions.

(iv) Immediate action as regards rangefinders

The Committee consider that immediate action should be taken as follows:-

(a) The Admiralty be asked to immediately provide means of lower magnification as an alternative to the present high power. It is understood that this could be applied to all existing range-finders by the provision of a special face-piece.

(b) The supply of one 15 ft rangefinder to each capital ship should be hastened.

(c) The provision of yellow tinted shades for use on rangefinders in misty weather should be proceeded with.

(d) All rangefinder mountings (not in turrets) should be fitted with bearing racers, particularly in light cruisers.

(e) In light cruisers every possible means must be taken to reduce vibration of the rangefinder platform.

(f) The training of operators must be intensive and on standardised lines. Note: This point will be dealt with separately as regards B.C.F.

(g) Further arrangements to reduce to a minimum the interval between the cut being obtained and its appearance on the plot.

(h) The capacity of a Sextant type of rangefinder to give rapid indication of change of enemy course should be investigated. The new type of Hurliman rangefinder might be used to start with on a ship zigzagging at the extreme range obtainable in Scapa Flow.

It is probable that by working on the masthead height and apparent ship's length a very much quicker indication of change of course would be obtained than is the case with the present rangefinder.

(i) A high power glass fitted with a pair of vertical and also a pair of horizontal cross wires, one wire of each pair being adjustable, was suggested some years ago in this connection, and might prove effective.

Trials on the above lines are recommended.

6. (b) THE USE OF DEFENSIVE TACTICS TO AVOID BEING HIT

(i) To have the best light is an enormous gunnery advantage. All Gunnery Officers emphasise the extreme difficulties when firing to the Eastward on 31st May when, on the contrary, (as observed by ships not then engaged), ships to the Westward made a splendid target. This must be taken into consideration in future tactics.

(ii) Alteration of own course did not hamper the control and director layers to any great extent, and it should be understood that in this respect Gunnery must meet the requirements of tactics. Future practices for B.C.F., both rangefinding and firing, should allow for this. It is imperative for ships to slightly alter course for defensive purposes, when to do this must be left to the discretion of Captains of ships, and certain limitations to govern this matter should be laid down.

7. (c) THE SAFETY OF MAGAZINES AND AMMUNITION

The Committee are of opinion that the following points with regard to magazines and ammunition are established:—

Turret Magazines

(i) With existing designs of turrets it is impossible to safeguard the Handing Room from the flash of a shell burst, or from cordite flash caused by shell burst, in the gun-house or working chamber.

(ii) Magazines must therefore be able to withstand flame under pressure, and in this connection it is pointed out that the bulk-heads of Q Magazine in Lion were considerably buckled, although they were supported by the water which, by then, had probably completely flooded the magazine.

(iii) Doors opening inwards into the Magazine from the Handing Room are extremely dangerous and should be altered immediately.

(iv) One of the venting plates in Lion admitted a tongue of flame into the Magazine; this plate was of the old type, and had not been modified in accordance with A.W.O. 1331 (D.2945/15 - 13.8.15) and G.F.G.O. No 459 - 15.5.16. All ships should have this alteration fitted forthwith.

(v) The type of handing scuttle finally decided to be fitted must be designed to withstand the pressure mentioned in (ii), and it is highly undesirable that the handing scuttle or airlock should contain more than one-quarter charge at a time, owing to the consequent danger of bursting the airlock.

6" and 4" Magazines

(vi) It is the opinion of the Gunnery Officers of the B.C.F. and 5th B.S. that it is too dangerous to the safety of the ship to keep the magazine hatches of the secondary armament open in action, excepting when actually obligatory for replenishing the ready supply kept in cases at the guns. Wherever it is possible, handing rooms with airlocks must be fitted without delay to all 6" and 4" magazines. A letter with definite proposals for the 4" Magazine of Lion class has, we understand, already been forwarded to you. This alteration is still more vital in the case of light cruisers, where the magazine must of necessity always be kept open when engaged.

Stowage of ready use cordite at guns and method of transport to guns

(vii) K.A. cases containing charges have been proved dangerous in action in more than one ship. For secondary armaments flame-proof stowage for 20 single charges must be provided at each gun, the ordinary ammunition cases being used to replenish this ready supply whenever required. Dredger hoists should never be used for cordite, but only to replenish shell when the ready supply is exhausted. At other times they must be kept closed down. A similar type of flame-proof case is also required in light cruisers, and in addition these must be used for transport from the magazines to the battery and for storage on deck in all weathers.

Igniters

(viii) The danger of a chain of cordite conveying fire from the gunhouse to the magazine is invited by the system of permanently attaching the igniters to the charges. The advisability of altering this should receive the immediate attention of the Admiralty as affecting the safety of our ships in the next action. It is known that trials were carried out some years ago in which the igniter was secured to a hook on the mushroom head. This method, however, is not now advocated owing to the high temperature which the mushroom head reaches after long firing; and it is preferred to place the igniter on the rear quarter charge (only) whilst on the gunloading cage tray, immediately before ramming home, — a wooden packing piece being fitted in rear of the cordite compartment of the gunloading cage so that on delivery of the cordite there is enough clearance between the rammer head and rear quarter charge to affix the igniter. This important question is also entirely applicable to handworked B.L. guns.

Drowning exposed charges

(ix) There is a strong expression of opinion that some extremely rapid method of flooding is required for all cordite positions in a turret or battery outside the magazine. With this the Committee entirely concur, and accordingly forward herewith a proposal placed before them by Engineer Commander W. C. Johnson, H.M.A.S. Australia [not included]. In the meantime they strongly recommend that, as a temporary measure, an immediate and ample supply of water should be stored at every position where exposed charges lodge during their transport to the gun. For this purpose a 25 gallon drum is recommended. Had it been possible to rapidly drown the charges in the handing room hoppers and main cages of Q turret in Lion, it is possible that the second and belated explosion might have been prevented, so saving many casualties and much damage to material.

Mantlets

(x) It was proved in Southampton that on the upper deck a rope mantlet saturated with water prevented the flame of a bad cordite fire reaching the other charges at the top of and in a neighbouring ammunition trunk, and in addition saved the supply party. The Committee therefore urge that the fullest use should be made of this method, and that so far as possible every gun with its ready supply of ammunition and every supply opening should be completely screened by saturated mantlets.

See Also

• Additional Report of B.C.F. Gunnery Committee

Bibliography

• Beatty, Admiral of the Fleet David, First Earl (1989). Ranft, Bryan McL. ed. The Beatty Papers: Selections from the Private and Official Correspondence of Admiral of the Fleet Earl Beatty. London: Navy Records Society. ISBN 0-85967-807-5.