DECISIONS.

GENERAL.

1. To perfect services of information and communication, so that hunters will be given timely information of enemy submarines operating in their vicinity, and so that aircraft, surface vessels and friendly submarines may all have their efforts coordinated. There should be the freest possible flow of information to and from all units.

WEAPONS.

2. Every vessel should consider its guns and ram the most effective antisubmarine weapons at night or in thick weather and plan its actions accordingly.

3. To determine experimentally the relative value of heavier depth charges; lashing two 300-pound depth charges together is suggested as a substitute for our 600-pound depth charge.

TACTICS.

4. To mark the line on which close contact with a submarine was made by dropping a buoy and simultaneously observing the compass bearing of the submarine, and thereafter to use this line as an origin. of maneuver. See rules on page 275.

5. To organize on each vessel a depth-charge crew under a depthcharge officer, and to give special attention to the training of these and to the system of signals and the doctrine governing their action. See page 278.

6. To experiment with the antennæ mine as a tactical antisubmarine mine, and to supply a part of all escort vessels with these mines as soon as developed. Large handy vessels in certain convoys to be used as tactical mine barrage vessels.

7. To continue present plans for hunting by sound with chasers and submarines; areas for the latter to be separated from other antisubmarine effort.

8. To counterattack with a large force on each occasion when a convoy is attacked, and to continue the attack with a considerable portion of the escort. Drive the submarine under, keep him under, and impose upon him the attitude of the hunted instead of the hunter. 9. To organize in each escort a regular hunting unit with definite plans of action.

10. To organize sight hunting units for operations in northern latitudes during summer and along routes between enemy bases and operating grounds.

11. To organize similar units of small vessels for narrow waters. 12. To use kite ballooons whenever possible.

13. To issue depth charges to vessels of fast convoys so that whenever the tactical situation makes the safety of the vessel lie in the turning toward the submarine it may use depth charges freely.

14. To place depth-charge throwers on transports and cargo vessels which have a suitable personnel.

15. To direct submarines to use torpedoes freely upon every profitable opportunity for attack.

INVENTIONS.

16. To develop a marker shell that can be fired at a submarine about to submerge, which, upon hitting the water, will explode and leave a small smoke producer on the surface at the point of impact is urgently needed.

17. To design depth-charge throwers so as to permit of variations of range and train.

18. To develop as soon as possible up to the point of readiness for quantity production a type of mine that does not depend in any degree for its efficiency on secrecy regarding its design.

19. To develop a torpedo-firing mechanism that will be sensitive to the presence of a vessel within 70 feet of the torpedo, and to attach this firing mechanism to all torpedoes used in antisubmarine warfare.

20. To develop a mine-firing mechanism that will be sensitive to the presence of a vessel within 100 feet of the mine, with a view to using this mechanism in antisubmarine mines.

[Extract from Memorandum No. 71, "History of Planning Section."]

This problem was undertaken by the Planning Section because we felt that antisubmarine methods and means then employed were not sufficiently effective to meet the menace against allied sea communications. The recent enemy successes on land appeared to render important a consideration of the subject. Believing that the best solution of the submarine problem was tactical, we endeavored to deduce the best tactical methods for combating submarines.

This memorandum was mimeographed and distributed to United States vessels in the war zone.

MEMORANDUM No. 42.

TESTING MINES.

30 July, 1918.

Sixteen thousand American mines have been laid in the Northern Barrage without any means of testing them as to the efficiency of their depth-taking gear. It is possible that the mine anchors are not functioning properly. It is extremely important that every possible assurance be given that the mines and mine anchors are functioning as designed.

RECOMMENDATION.

(a) That experiments be conducted immediately in Loch Ness with a considerable number of mines, laid as nearly as possible under service conditions, in order to check up the reliability of the depthtaking mechanism. Mines thus laid may be rendered safe by removing the K device previous to laying.

(b) That the surface mine barrage already laid be tested as soon as possible by running a skimming sweep, set for a depth of 10 feet, across the barrage and normal to it, in several places, so as to determine the effectiveness of the mines nearest the surface that have already been laid. Unless this is done we shall have no conclusive assurance of the effectiveness of our mining effort.

289

MEMORANDUM No. 42a.

NOTES ON VISIT TO FRANCE, JULY, 1918.

(By Capt. D. W. KNOX and Capt. H. E. YARNELL.)

[Data relating to quantities of materials and troops to be handled at French ports, together with data concerning port facilities, are appended.]

5 August, 1918.

BREST.

Ten thousand troops can be handled daily, and 150,000 can be quartered in the immediate vicinity; 40,000 were landed recently in 12 hours. It is understood that the United States Army will sooner or later take over the railroad from Brest, which will considerably increase its capacity. The troop capacity of Brest would appear to indicate the desirability of making it the only port for landing men; present plans contemplate landing 60 per cent there. The facilities for handling stores are greatly congested at present, and steps are under way to increase the capacity by driving piles alongside the breakwaters to add to berthing space. However, Brest will probably be a secondary port so far as the landing of supplies is concerned.

The relations between the Army and Navy are most cordial, and complete cooperation exists.

Brest is greatly congested and sanitary conditions are poor. Steps are under way to increase the water supply of the city, which will improve conditions.

The destroyers at present based on Brest are worked to the limit, and an early addition to this force seems a necessity. No more than 12 additional destroyers can be accommodated at present. By January next expected developments should provide harbor facilities and fuel for a total of about 60 destroyers. There will be storage capacity for 28,000 tons of oil by September first.

L'ORIENT.

At present there is no need for destroyers, so long as the practice of routing convoys via Brest is continued.

The convoys eventually should be routed direct to and from Loire ports, and then destroyers should be based at L'Orient.