Minute from First Sea Lord to Prime Minister

[PREM 3/ 163/ 1] 5 November 1942

Carrier reinforcements for South West Pacific Herewith are two preliminary investigations dealing with the possibility of reinforcing the S.W. Pacific after “Torch”, on the basis that we suffer no casualties to important units during that operation. The situation will be again reviewed when we know how “Torch” has fared.

Appreciation by Admiralty

[PREM 3/ 163/ 1]

Carrier reinforcements for South West Pacific

Carrier Reinforcement of S.W. Pacific

The attached appreciation shows that in naval forces the Americans will be inferior to the Japanese in the South West Pacific until next Spring, even if we reinforce them by three aircraft carriers. Without these reinforcements they will be markedly inferior, and the security of the trans-Pacific air and sea routes may be endangered. Even if Guadalcanal falls, provided we dispute further Japanese advances to the South and maintain pressure in New Guinea, the Japanese should be sufficiently contained in the Pacific to prevent them from carrying out any major operations elsewhere.

2. It must be emphasised that with the limited knowledge of the naval, air and land forces engaged in this theatre which is available in the Admiralty, this conclusion must necessarily be somewhat speculative. Moreover, in our calculations we have made allowance for U.S.S. RANGER reinforcing this area after “TORCH”, though the Americans do not apparently like exposing this ship to any severe test on account of her poor underwater protection.

The Indian Ocean

3. Activity in the South West Pacific, combined with the general shortage of shipping will, in our opinion, limit Japanese activity in the Indian Ocean to naval sorties and carrier-borne raids against shipping or harbours. There are two methods of countering this:–

(a) By superior naval forces based in Ceylon and

(b) By shore-based air forces, adequate to cover coastal shipping, ports and anchorages.

In addition naval escort against raiders will be required for important convoys outside the protection of shore-based air.

4. Owing to our shortage of aircraft carriers and destroyers, we are unlikely to be able to provide in the first half of 1943 an Eastern Fleet superior to the naval force which the Japanese could make available were they to accept risks in the Pacific area. Since the weaker Fleet is unable to provide protection, our proper course is to rely on anti-raider escort by cruisers, backed up by flying boat and shore-based reconnaissance and air striking forces. In accepting this course, we necessarily accept diversion or stoppage of trade during the period of any Japanese sortie in strength. This, however, should not be of very long duration in view of their inability to seize advance bases while contained in the South Pacific.

5. It therefore follows that by reinforcing the South Pacific with major units of the Eastern Fleet and so increasing the scale of attack which the Japanese must bring to bear concurrently with the threat which the Allied forces can mount, we should be able to do more to increase the security of the Indian Ocean than by retaining in this area a weak Eastern Fleet. Of such action, the build-up of flying boat and shore-based air forces in the Indian Ocean is a corollary.

The Atlantic Ocean

6. With the GRAF ZEPPELIN possibly in service by early 1943, two large Fleet Carriers must be retained in the United Kingdom or at Gibraltar to allow for docking and repairs.

If all other Fleet Carriers were to be detached to the South Pacific, the chances of giving increased protection to Russian convoys by the Home Fleet would be lessened, since the risks involved would be greater. Supplies to Russia by the Northern route may even increase in importance next year. Even if German air strength in Northern Norway deteriorates therefore, we are unlikely to be able to exploit it by providing adequate air protection for the Home Fleet east of Bear Island.

The Mediterranean

7. The Chiefs of Staffs have decided that our main amphibious operations in 1943 should be conducted in the Mediterranean with the object of stretching the enemy forces to the greatest possible extent. They have also recommended that in this theatre we should first aim at:–

(i) The elimination of Axis forces in North Africa from the East, together with such assistance as can be rendered from the West.

(ii) The capture of Sardinia from the West at the earliest opportunity. Given adequate shore-based air forces on the North African coast at either end, cover of convoys to support the elimination of Axis forces in Libya should not require the presence of capital ships or carriers.

8. Investigations into the capture of Sardinia have, at present followed two lines:–

(a) capture by direct assault of Cagliari and (b) the capture of Cagliari by overland advance from the West coast.

Owing to lack of intelligence no decision has yet been possible as to whether a direct assault on Cagliari is feasible but, if it is, we could establish our fighter forces ashore very much more quickly by this means. Air support for the assault could probably be provided from Tunisia by long range fighters amplified by fighters from Auxiliary Aircraft Carriers. To interfere with a direct assault on Cagliari, the Italian Fleet must accept the threat of heavy air attack from Tunisia. Were this threat adequate, no heavy Naval covering force and therefore no Fleet carriers would be necessary against the Italian Fleet.

|The alternative plan involves carrier borne air support for several days until the Army has captured Cagliari and its aerodromes. To cover this West coast landing, a force of 3 battleships and 2 carriers would probably be necessary to guard against interference by the Italian Fleet from the North. This alternative plan is probably not feasible unless the enemy fails to reinforce his land garrison and the strength of the German Air Force in the Mediterranean is much reduced.

9. For offensive naval action against the French or Italian Rivieras, the support of Fleet Aircraft Carriers would be required. Similarly, for any operation against Sicily, Fleet Aircraft Carriers would be needed to support heavy naval covering forces.

10. To sum up, if no Fleet Carriers can be made available for the Mediterranean the capture of Sicily is probably not possible. The capture of Sardinia might, however, be possible if a direct assault can be made on Cagliari. In this event we must, therefore, forego any hope of reopening the Mediterranean to a full flow of traffic. By denying ourselves offensive Naval sorties such as the bombardment of Genoa, we also curtail our ability to increase the liability of Italy to Germany.

Summary of the Problem

11. Our broad strategy is to defeat Germany, diverting from that object only the minimum forces necessary for the safeguarding of our interests in the East. The problem before us, therefore, lies in the interpretation of the word “minimum”. On the one hand, without British support, the American trans-Pacific trans-Pacific air and sea routes may be endangered by the Japanese; on the other hand, with only two large carriers in the North Atlantic, we are unable to exploit our Mediterranean strategy to the full and cannot hope fully to reopen that area to our shipping.

12. We must avoid dividing our carrier forces into small groups. If we are to reinforce the Americans we must do so on as large a scale as possible, not only because any compromise will fail to achieve our object of containing the Japanese in this area, but also because weak reinforcements will subject us to greater risks of attrition.

13. We shall get no new Fleet carriers until 1944, when INDEFATIGABLE and IMPLACABLE come into service. By mid-1944 the Americans expect to complete eleven Fleet carriers and nine converted cruiser carriers additional to their present forces.

14. Unless we support the Americans to the utmost of our ability in the present emergency, we are unlikely to gain naval support for European operations – possibly in the Mediterranean – in the latter half of 1943 when the South Pacific situation should have been retrieved.

15. From the foregoing arguments and, of course, subject to any casualties sustained in “TORCH” and a satisfactory solution to the problem of the French Fleet, I recommend that we should reinforce the American naval forces in the South Pacific at the expense of the Mediterranean and Indian Ocean during the next six months.

Conclusion

16. This appreciation only deals with the question of Carriers. A separate paper on the Battleship problem is attached.