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Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters, to Rear Admiral Henry B. Wilson, Commander, United States Naval Forces in France


6 copies           


10 June, 1918.     

From:     Force Commander.

To  :     Commander, U. S. Naval Forces in France.

Subject:  Troop Convoys.

     1.   Meeting Convoys.

          On the completion of the transfer of approximately 10 destroyers from Queenstown, you are assigned the additional duty of providing escort for all troop convoys bound for the French coast.

          The following cable as recently received from the Department is quoted:-

“Department desire you put extra emphasis upon the duty of escorting troop convoys both in number of destroyers and distance to which they operate. If necessary in order insure safe landing of troops fewer destroyers shall be assigned to the protection of ships carrying merchandise.”

     2.   Schedule of Troop Convoys.

          I have requested the Department to sail convoys every 7 or 8 days so as to avoid congestion on the French Coast, reduce the size of convoys, and permit destroyers to be used most efficiently. There are now some 50 transports carrying troops to the French Coast, and it is to be expected that convoys of good size will be sailed regularly.

     3.   Position and Hour for Meeting Convoys.

          The position at which convoys are to be met is left to your judgment, depending somewhat on the area of operations of enemy submarines. The rendezvous should be made well to the westward, so as to furnish as much protection as practicable against submarines on passage between Germany and Azores or Mediterranean. It is considered very undesirable to meet convoys during darkness. Joining at daylight or shortly after assures to convoys the protection of darkness through part of zone. On joining a convoy the senior officer of the escort should be careful to communicate with the Senior Officer present, who is generally in the cruiser. Communication can then be had with the Senior officer of the convoy if he is not senior officer present. One or two instances have arisen where destroyers ignored the Senior officer present, and friction and delay followed.

     4.   Use of Term “Rendezvous”.

          Some confusion has arisen in the past due to destroyers escorts informing troop convoys that the escort were at the rendezvous, or have passed the rendezvous, and so forth. This is very misleading to troop convoys, because troop convoys are assigned a rendezvous well to the westward and have no information other than that they are to maintain position on the line and at the prescribed speed over the ground until met. In communicating with troop convoys destroyer escorts should avoid the use of the word “Rendezvous” unless they are referring to the rendezvous given troop convoys, this rendezvous being the one previously referred to as being well to the westward of the meridian where convoys are ordinarily met.

     5.   Routes. 

          Routes for troop convoys should be prescribed by you, to be furnished the Senior Officer of the convoy when the escort joins. It is considered important that convoys be routed so as to approach the coast approximately at right angles to the line of soundings. It is desirable that routes be broken by changes of course, so as to make it impossible for enemy submarines ahead of the convoy to be kept informed of the direction of approach. After studying the data available in the Admiralty I am of the opinion th<a>t the safest position for shipping approaching or leaving French Atlantic ports to cross the 10th Meridian, is between Latitude 44º30’ and Latitude 46º30’. Less thick fog is to be expected along this route. It is believed advisable to route shipping clear of the approaches to the English Channel. The area west of the English Channel is a focal area for shipping to the Irish Sea, Bristol Channel, and English Channel. Other things being equal, this area is ordinarily to be avoided; not only on account of the likelihoodd of submarines, but of congestion of shipping, especially of independent sailings. With very fast ships somewhat greater latitude in routing is permissible. Nothing in the foregoing paragraph is to be interpreted as limiting in any way your authority to route shipping to the best advantage to avoid enemy activities, as well as other convoys.

     6.   Size of Escort.

          The number of escorting destroyers assigned to a convoy depends on the size and number of ships, number of troops on board, submarine activity and so forth. The following table may be taken to represent the approximate escort that should be provided for troop convoys with transports of moderate size. This table is a general guide only, and is to be modified as necessary to meet conditions:-































          In general, large convoys are safer than small ones, as the larger escort makes it more dangerous for submarines attempting to deliver attacks. Experience has shown that one escort vessel is an inadequate escort with any type of ship. When submarines are operating inshore near the routes of convoys it may be possible to augment the escort while passing through the most dangerous waters.

     7.   Splitting Convoys. 

          In order to assist Army authorities to facilitate discharge of transports, I have agreed to split convoys to two destinations when it can be done without greatly increasing the risk to the troop transports. In future it will be unnecessary to refer to me the Army’s request to divert troop transports unless you are in doubt as to the propriety of splitting a convoy. I consider that protection of the convoy is of primary importance and the rapid discharge of ships is entirely secondary. In many instances it may be possible xxx xxxx to xxxx xx xxx xxxxx xxx xxx augment the escort so as to furnish good escort for both parts of the convoy, and when possible the wishes of the Army should be met.

     8.   Sailing Troop Transports Westward.

          In order to provide a maximum of protection to troop transports not only in the strength of escort but in distance to which vessels are escorted, it is desirable that as many troop transports as practicable be escorted to the westward by destroyers proceeding to meet the next incoming troop convoy. With convoys arriving every 8 days there should normally be about 4 days available for discharging transports, in order that the same transports may be taken to the westward by the destroyers detailed to meet the next troop convoy. Preference should be given to discharging the largest and most valuable troop transports in the convoy first, so that they can be included in the convoy referred to. Smaller and less valuable troop transports could be sailed later under special escort. The point to emphasize is that the strong escort going to the westward for a long distance should take with it if possible the most valuable ships of the preceding convoy. If the transports are discharged promptly it should be possible in the majority of cases to take to the westward all of the transports that arrived in the previous convoy. This will provide a regular flow of work and prevent congestion of ports.

     9.   Speed of Convoys and Protection.

          It is quite impossible to assemble a convoy in which some ships do not suffer a reduction in speed by sailing in convoy. It is desirable that the difference in speed of vessels in convoy should not exceed 4 to 6 knots; but with a strong escort greater latitude may be taken, especially if the escort proceeds well to the westward. In general, transports are grouped according to speed in United States, and it may be assumed that all vessels arriving in a convoy may be grouped together for sailing to the westward. Wherever possible, very fast ships should be grouped together, if suitable escort can be provided.

W. S. Sims            

Source Note: TDS, DNA, RG 45, Entry 517B.

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