Rear Admiral Albert Gleaves, Commander, Cruiser and Transport Force, Order for Ships in Convoy, Addendum
CRUISER FORCE U.S. ATLANTIC FLEET
U.S.S. SEATTLE, Flagship.
1 November 1917.
Addendum No. 1.
“ORDERS FOR SHIPS IN CONVOY” -- dated 10 Oct. 1917.
Insert after paragraph 81 of “Orders for Ships in Convoy” the following instructions taken from letter of Force Commander in Europe.
“In general with six destroyers and a convoy making good twelve knots or more, so that danger of attack from astern is small, the destroyers are disposed as shown in appended sketch A.
Before starting out from the base, the destroyers are given the number of ships in the convoy, the call letters of the ocean escort, the rendezvous of convoys and their route from the rendezvous, and are instructed to meet the convoy as far to the westward as conditions warrant. The convoy is to continue on the line until picked up by the escorting destroyers.
Destroyers are instructed to proceed to the rendezvous on a scouting line so as to cover a greater expanse of ocean and better assist in locating submarine, picking up boat crews, and so forth.
All destroyers have been instructed that for the present the ocean escort (cruiser) will return immediately [when] the destroyers join. If later the presence of raiders makes it desirable to escort our troopships westward in convoy it may be desirable for the ocean escort to continue into France and return with the same convoy. In this case the ocean escort should take a position as leader of the middle column of the convoy.
Radio is never to be used except in cases of urgency and when necessary to keep in touch with the convoy. Positions are not signaled in latitude or longitude, but by bearing and distance from the rendezvous.
It is the usual procedure for destroyers to assemble to the eastward of the convoy and then proceed west on a scouting line so as to make certain to intercept the convoy in the event of thick weather or any errors in position.
CONVOY UNDER DESTROYER ESCORT.
When destroyers join up with the convoy they will take the positions previously assigned by the senior officer of the destroyer escort or as modified by him due to weather, visibility and so forth. The usual positions are shown in appended sketch A.
During daylight hours the destroyers zigzag at an approximate speed of 15 knots, dependent on weather and fuel.
If a submarine is sighted it is expected that the convoy will immediately turn away from the danger and proceed in formation at full speed. One or two destroyers are assigned to attack the submarine while the rest of the destroyers continue with the convoy. Smoke screens may be used if conditions are favorable to assist in screening the convoy. Ordinarily the destroyer assigned to attack the submarine would remain in the vicinity of the submarine until the convoy is on the horizon, so that the attacking submarine would lose sight of the convoy, after which a considerable change of course would be made by the convoy in order to prevent submarines farther to the westward from attacking.
Convoys should not use their guns against submarines while under destroyer escort, except a warning gun to indicate the track of torpedo or presence of submarine. The attack against the submarine will be made by destroyers.
If a ship is torpedoed one or two destroyers are told off to stand by the vessel to save life or assist in salvage work while the rest of the destroyers continue with the convoy away from the danger. The destroyers usually indicate the presence of a submarine by firing a gun at the spot and blowing six short blasts on the whistle.
Immediately on the return of each destroyer escort the senior officer submits a report of operations together with any recommendations for improvement.
The senior officer present, whether in the destroyer escort or in the ocean escort or in the convoy, is in charge of all operations and his orders are to govern.
Owing to the wide experience of the destroyer captains in anti-submarine warfare, I quote the following from my report of August 30th:
“21. As previously reported, it is undesirable for the convoy commander to attempt to rigidly direct the operations of his escorting destroyers or prescribe any definite formations or positions relative to the convoy. In case of attack the destroyers according to their plan will operate directly against the attacking submarine independent of the convoy. Generally speaking, the best procedure for the convoy is to maintain its formation but turn away. Care should be taken to prevent interfering with the destroyers operations by gun fire from the transports.”