REFERENCE DOCUMENTS & RESOURCES - OFFICIAL ADMIRALTY DOCUMENTS
ADM 1/8586/70: FINAL REPORT OF THE POST-WAR QUESTIONS COMMITTEE (1920)
Updated 18-Oct-2007

This document is a modern transcription of Admiralty record ADM 1/8586/70. It concerning naval lessons learned from the First World War. It was transcribed by David Chessum on behalf of the the Royal Navy Flag Officers 1904-1945 website. The original file is held at the The National Archives at Kew, London. This Crown Copyrighted material is reproduced here by kind permission of The National Archives.

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73

INDEX.

I. – THE FLEET AIRCRAFT CARRIER

GENERAL REMARKS

Para .

Two types recommended

1

Reason for having torpedo planes in all Carriers

2

Additional types of Fleet Aircraft Carriers undesirable

3

Auxiliary Aircraft Carriers and depot ships

4

Suitability of “Furious,” “Courageous” and “Glorious” for Type “A”

5

Limitation to size of aircraft

6, 7

One type of machine for both reconnaissance and gunnery spotting

8, 9

II. – THE FLEET AIRCRAFT CARRIER, TYPE “A”

 

GENERAL CHARACTERISTICS-

 

Principal duty

10

Secondary duty

11

Other uses

12

High speed necessary

13

A depot and not a fighting ship

14

Aircraft Carriers must be Fleet Units

15

Duties cannot be combined with those of a Torpedo Carrier

16

Recommendation

17

Limitation to beam and draught

18

MAIN NAVAL REQUIREMENTS.

 

SPEED-

 

Margin of speed to regain position in Fleet after flying machines on and off

19, 20

Speed margin to escape enemy Light Cruisers if cut off

21

Recommendation

22

ENDURANCE

 

Endurance recommended

23

Definition of endurance

24

Oil fuel essential

25

ARMAMENT

 

Gun armament

26

Director firing

27

Anti-aircraft guns

28

Torpedo tubes

29

PROTECTION

30-32

Torpedo bulkhead

32

CAPABILITY OF FLYING-ON AND FLYING-OFF MACHINES

33-45

Deck dimensions

34-39

Funnel and mast

40

Flying on

41, 42

Flying off

43, 44

Conclusion

45

STABILITY-

 

Steadiness

46

Correction of heel

47

AIRCRAFT STOWAGE

48-51

DISPLACEMENT

52

EQUIPMENT

 

Flying arrangements

53

Lifts

54

Cranes

55

Control position

56

Searchlights

57

Wireless telegraphy

58

Stowage of petrol

59

Flying deck

60

Boats

61

Towing airships

62

III. – FLEET AIRCRAFT CARRIER, TYPE “B”

Cheaper and slower type

63

Risk of light cruiser attack accepted

64

Endurance 65
Recommendation 66
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74

 

I. THE FLEET AIRCRAFT CARRIER.

GENERAL REMARKS

1. Two Types Recommended. – Your Committee are recommending two types of Fleet Aircraft Carriers, differing only in speed and endurance.

There is no military necessity for the existence of more than one type, the second is put forward entirely for the sake of economy.

Type A. – Ships of great speed to work with the Scouting Forces.

Though capable of embarking machines of other types they would carry normally Reconnaissance Machines, supplemented by Fighters and one or more Torpedo units.

Type B. – Ships possessing a good margin of speed over the Battle Fleet.

Though equally capable of carrying other types of machines they would carry normally Torpedo Planes, Artillery Observation Planes and a few Fighters.

2. Reason for having Torpedo Planes in all Carriers. – Naval actions do not always work out “according to plan,” and opportunities may occur when the Senior Officer may find it convenient to order any of his Carriers to use her Torpedo Machines.

It is obvious that carrying them provides a detached Aircraft Carrier with a valuable means of self-defence.

3. Additional Types of Fleet Aircraft Carriers undesirable. – We strongly recommend that, for the present, no more than two types of Fleet Aircraft Carrier be considered.

As it is impossible to say what may occur to modify opinions in the course of the next few years, it appears very desirable to adhere to a general service type, more especially because, as previously stated, the provision of a second type is merely a question of expediency.

4. Auxiliary Aircraft Carriers and Depot Ships. – These are dealt with in the Report on Paragraph 4 of our Terms of Reference: we are not recommending that vessels should be specially built for either of these services.

5. Suitability of “Furious,” “Courageous,” and “Glorious” for Type A. – We suggest that if the “Furious” could be rebuilt, either with a flush upper deck or on the “island” plan, she would be a suitable vessel of the faster type and, further, that is would probably be cheaper to similarly convert “Courageous” and “Glorious” than to build two more Aircraft Carriers.

6. Limitation to size of Aircraft. – We consider that the primary factor affecting all Fleet Naval Aircraft (as distinguished from flying boats) is that their size must not be too large to permit of their flying on to the deck of the Carrier in safety.

7. This restriction rules out, for the existing Carriers, the three-seater Artillery Observation Planes used by the Atlantic Fleet in the Autumn of 1919.

So far as is known, none of the three-seater planes have yet been worked from a Carrier; in other words they could not yet be taken away from Home Waters in war with the certainty of flying-off and on. If they are proved to be an absolute necessity, then all future Aircraft Carriers must be designed to carry them, but it is obvious that there must be limitations to the size of floating aerodromes. This question is more fully dealt with under para. 51 of this Report.

8. One Type of Machine for both Reconnaissance and Gunnery Spotting. – It appears very desirable to your Committee that the same type of machine should be used for Reconnaissance and Gunnery Spotting, as has been the case since 1918.

9. It is unnecessary to point out the advantage of interchangeability of aircraft when the necessary limitations in the numbers of Aircraft Carriers and in the capacity of their hangars are considered.


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II. THE FLEET AIRCRAFT CARRIER, TYPE “A.”

GENERAL CHARACTERISTICS.

10. Principal Duty. – The principal function of the Fleet Aircraft Carrier is to ensure that the force with which she is operating is self-contained for Aerial Reconnaissance, which, under ordinary conditions, should continue whilst required. She must be capable of flying-on machines for relief or replenishment whilst remaining in touch with, and protected by, the main force.

11. Secondary Duty. – Her secondary function is to provide in action the aircraft necessary for local command of the air and for aerial offensive against the enemy’s surface craft. When necessary she can carry Reserve Gunnery Spotting Machines.

12. Other Uses. – She will also be used for special operations as a mobile advanced base, enabling aircraft either to attack the enemy’s bases or forces or to reconnoitre his defended waters, for which purposes she may operate either alone or supported.

13. High Speed necessary. – For all of the above duties high speed is necessary.

14. A Depot and not a Fighting Ship.- The functions of the Fleet Aircraft Carrier as a shp are those of the Depot rather than the fighting ship, and the armament that she carries, in addition to her aircraft and their weapons, should be one purely for defensive purposes.

15. Aircraft Carriers must be Fleet Units. – The successful tactical handling of these ships will not be easy, and the rapid despatch and reception of aircraft will call for the same high degree of organisation, training and practice that is necessary in any form of modern warfare. This constitutes the strongest argument for Fleet Aircraft Carriers being henceforward just as much integral units of the permanent Fleet, trained and ready for war, as are other types of warships.

16. Duties cannot be combined with those of a Torpedo Cruiser. – Suggestions have been made that such craft should be designed also as Fleet Torpedo Cruisers, on account of their high speed. Such a course would produce at the outset a source of confusion and failure in action. It is impossible to expect a Carrier to manoeuvre for the position of torpedo advantage in the van of the line of battle, and to remain during action in that position firing torpedoes, whilst she should be manoeuvring freely in safety to fly-off and fly-on her machines.

17. Recommendation. – Your Committee, therefore, recommend that no torpedoes, other than those for use from aircraft, be included in the armament of these ships.

18. Limitation to Beam and Draught. – We recommend that the limiting beam and draught should be the same as for Capital Ships, viz., 106 ft. beam and 30 ft. draught.

MAIN NAVAL REQUIREMENTS.

SPEED.

19. Margin of Speed to regain position in Fleet after flying machines on and off. – When Aircraft Carriers are operating in tactical conjunction with fighting ships, their first necessity is for a considerable margin of speed. This has been demonstrated frequently in practical experience, and it must be obvious when it is considered that the nature of their work requires them to maintain station on the fighting ships and also frequently to drop astern whilst flying-on machines. Should the wind be right astern, the ship must turn through 16 points, remain on an opposite course to the fleet whilst the machine is flying-on, and then turn back through 16 points; the distance thus lost may amount to many miles after flying on only one machine, and allowance must be made for flying-on being of frequent occurrence.

20. Loss of position will likewise occur on every occasion of flying-off a machine if (as in “Furious”) the Carrier is unable to fly-off machines into the “relative wind.”

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21. Speed margin to escape enemy Light Cruiser if cut off. – Aircraft Carriers are the most vulnerable type of ship with the Fleet, both by reason of their high freeboard and light construction, the fragile and inflammable nature of the contents of their hangars, and the large stores of petrol carried. On the special operations for which they may be required in enemy’s waters, involving waits for the return of aircraft, they will be liable to be cut off, hence their speed should be such as to enable them to run from enemy light cruisers

22. Recommendation – On all of the above grounds we consider that a speed of at least 33 knots is necessary.

ENDURANCE.

23. Endurance recommended. – Endurance for fleet work should be greater than that of the Fleet on account of the extra distance Carriers have to steam. We recommend an endurance at 18 knots of 1,000 miles more than the Battle Cruiser, namely 6,100 miles.

24. Definition of Endurance. – Official endurance is 15 per cent. less than the maximum distance which can be steamed on the fuel carried.

25. Oil Fuel essential. – Oil fuel is an essential, both in order to attain endurance and on account of fuelling considerations in this type of ship, where coal dust would cause serious inconvenience in the hangar.

ARMAMENT.

26. Gun Armament. The Gun Armament of the Fleet Aircraft Carrier is a defensive one. Given sufficient speed, she should not have to fight light cruisers.

We therefore recommend 4.7-in. guns, so mounted as to have a broadside of eight, thus giving a margin of superiority over destroyers.

27. Director firing. – Firing by director is a necessity.

28. Anti-aircraft Guns. – For anti-aircraft armament, at least four guns of 3-in. or whatever calibre is decided on for battleships, and as many anti-aircraft machine guns as possible.

29. Torpedo Tubes. – No torpedo tubes should be carried.

PROTECTION.

30. Generally speaking, the requirements are a light cruisers’ armoured protection combined with the under-water protection of a battle cruiser. Thanks to her speed, she need not be designed to resist a heavier gun than the 5-in., firing H.E. shell.

31. With regard to the necessity for horizontal protection, it must be remembered that the stowage of petrol and bombs, in addition to her gun ammunition, must be considered, e.g., “Eagle” carries 15,000 gallons of petrol and 38 tons of bombs.

32. Torpedo Bulkhead. – As this ship must reach a large displacement we recommend that a torpedo bulkhead should be worked into the design.

CAPABILITY OF FLYING-ON AND FLYING-OFF MACHINES.

33. Under all ordinary weather conditions Aircraft Carriers must be able to fly on and fly off machines with the maximum of reliability in the minimum of time.

34. Deck Dimensions. – Even a large ship represents a very small aerodrome, and even under the best conditions it cannot be guaranteed that a machine can alight exactly where desired.

35. Landing on a ship’s deck is a delicate operation, calling as it does for flying skilful enough to judge contact to within a few feet and to co-operate with mechanical contrivances outside the pilot’s control.

36. Consideration should be given to these points before deciding on other grounds the displacement of a Carrier, and hence the size of her flying deck.


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37. The ideal Carrier would have a perfectly clear upper deck like the “Argus”; if this ideal is at present unattainable, we must adhere to the “island” as designed in “Eagle” and “Hermes,” which also is very convenient for navigational and signalling purposes.

38. As to the breadth of the deck; the “island” narrows it considerably amidships, so the width should be the greatest that can be arranged for the size of the ship; the increasing size and wing-span of Fleet Aircraft demand the greatest space that can be provided until a fast flush-decked ship can be attained.

39 We recommend a horizontal deck, 800 ft. long and not less than 106 ft. broad, including, if absolutely necessary, a narrow stream-line-shaped island at the extreme side of the ship to contain the funnels and navigating position, etc., this gives the clean flow of air over the ship in which alone machines can keep under control whilst flying-on.

40. Funnel and Mast. – If a vertical funnel is necessary only one should be fitted, which should be of stream-line section. The mast should be for W/T only.

41. Flying-on. – On this deck there must be apparatus for arresting and holding the machines when they alight and, in addition, power-worked palisades around the ship to supplement the arresting apparatus in case of its failure; also to transform the bare deck into a comparatively calm enclosure where work may be carried on with rapidity and safety to machines and men.

42. The flying-on deck should be cambered away right aft.

43. Flying-off. – For flying-off, in addition to the flush fore-part of the deck, a turn-table securing position for pointing and slipping the smaller machines into the relative wind is desirable, in order to avoid, whenever possible, the necessity for large alterations of course.

44. It is possible that machines will be able to fly-off obliquely across the deck in a beam wind, and safely negotiate the violent uprush of air which must be met at the ships’ side under those conditions, but such a practice must always contain the elements of uncertainty and danger, as well as being clumsy in the deck arrangements for securing the machines.

45. Conclusion. – We recommend, briefly, that every Aircraft Carrier be fitted out to enable her to work the largest type of machine likely to be able to fly-off and fly-on to her deck.

STABILITY.

46. Steadiness. – In view of the difficulties inherent in flying-on, the steadiness at sea of an Aircraft Carrier should be as great as it can be made. Our Naval Attache in Tokyo reports that it is understood the Japanese are adopting the principle of gyro-stabilisation in their new Carrier.

47. Correction of Heel. – Rapid correction of heel is a necessity. In “Hermes” this can only be effected by the transference of oil fuel, which is too slow a process.

AIRCRAFT STOWAGE.

48. The military value of an Aircraft Carrier depends upon the type or number of the machines she carries, and therefore her aircraft stowage in relation to her size must be as high as possible.

49. Internal combustion engines may some day be suitable for Carriers, which will greatly increase the space available for hangars.

50. In the later stages of the war, the complement of machines for the “Furious,” whose definite duty was scouting for the Fleet, comprised Reconnaissance Planes, Torpedo Planes (one unit of three) and Fighters.

51. It is assumed that the duties of Reconnaissance Planes and Gunnery Planes (artillery observations planes) will be performed by the same machine and that, therefore, part of the Fleet Aircraft Carrier’s outfit will be available as reserve gunnery


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machines. Taking the stowage capacity of the “Eagle’s” hangar to be […] “Panthers,” and four torpedo machines as occupying the same space as [five?] “Panthers,” we show below a possible allocation of planes in five Fleet Aircraft Carriers, which is the number you Committee have allotted to a fleet consisting of two Battle Fleet Units and One Battle Cruiser Force Unit.

Note. – The “Panther” is referred to as a typical two-seater reconnaissance aeroplane of known dimensions.

Types of Aeroplanes

Carrier

No. 1

Carrier

No. 2

Carrier

No. 3

Carrier

No. 4

Carrier

No. 5

Reconnaissance

15

20

12

10

12

Fighter

7

7

7

7

7

Torpedo

6

3

9

B* 9

9

B* = Bombers (size assumed to be 1½-times that of “Panther” would probably be embarked only for special operations, otherwise the allocation for Carrier No. 4 would be as for Nos. 3 and 5.

DISPLACEMENT

52. Sufficient examination has now been made of the essential characteristics of the ship to enable the question of displacement to be considered.

The displacement must depend upon –

Speed,
Endurance,
Aircraft stowage and Deck dimensions.

All of the necessary qualities enumerated call for a ship of large size.

EQUIPMENT.

53. Flying Arrangements. – Reference has been made to the arresting gear and power-worked palisades necessary; a transverse palisade abaft the flying-off deck is recommended to enable machines to be handled aft whilst flying-ff is taking place forward.

54. Lifts. – There should be two or more lifts, one forward for machines being despatched, one further aft for machines returning to the hangar. We recommend that the size of lifts be not standardised, but that they should be made as large as practicable without undue interference with hangar-space below.

55. Cranes. – One crane abaft the “island” capable of hoisting in machines larger than any now in use with the fleet.

56. Control Position. – A stream-line-shaped control position, of light cruiser size, immediately abaft the navigating bridge on the “island.”

57. Searchlights. – Four 24-in. and two 10-in. searchlights are required, all for signalling.

58. Wireless Telegraphy. – General equipment for a battle cruiser in addition to aircraft sets.

59. Stowage of Petrol. – Reference has been made to the large stores of petrol carried. It is recommended that no system of stowage in bulk or of distribution by pipes be considered, but that it be stored in tins, with a handing-room between store room and lift. It is understood that proposals have been made to fit a petrol system in the “Hermes” on the principle of that installed in an aerodrome.

60. Flying Deck. – Should be coated with some substance that provides good foothold.


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61. Boats. – Two pairs of davits should be fitted that are capable of hoisting C.M.B.’s or D.C.B.’s.

62. Towing Airships. – An Aircraft Carrier, in addition to dealing with heavier-than-aircraft, should always be prepared to take airships in tow for re-fuelling or change of crews. No extra fittings are required for this duty.

III. FLEET AIRCRAFT CARRIER, TYPE B.

63. Cheaper and Slower Type. – Your Committee have considered the question of building a cheaper type of Fleet Aircraft Carrier, having a speed of five knot more than the Battle Fleet, viz.: - 26 knots instead of 33 knots. Such a vessel would probably perform the necessary work involved in keeping station with Battleship while flying off and on machines, but would suffer from the disadvantage of insufficient speed to escape from the enemy’s Light Cruisers.

64. Risk of Light Cruiser attack accepted. – Your Committee consider that the risk of Light Cruiser attack can be accepted, as these Carriers should always be in company with the Battle Fleet.

65. Endurance. – The official endurance required is 600 miles more than that of the battleship, namely, 6,600 miles at 14 knots.

66. Recommendation. – We recommend, therefore, that Aircraft Carriers with this speed should be built in the proportion of two-thirds of the total.

In all other particulars, except that of speed and endurance, they should be similar to the 33-knot type.

END OF TRANSCRIPTION