Naval History and Heritage Command

Commander David McD. Le Breton, Commander, Alywin, to Captain Richard H. Leigh, Commander, Submarine Chasers, Distant Service

[Extract]

C O P Y­_

U. S. S. ALYWIN,   

April 4, 1918.

FROM:  Commanding Officer.

TO:    Captain R.H. Leigh, U.S. Navy.

Subject:  Report of operations – March 29 – April 3. . . .

     CONCLUSIONS.

(a) The object of this patrol was primarily to protect the transport routes to Havre, owing to the large number of troops that were crossing at this particular time. Little hope was entertained of being able to conduct a successful hunt in this vicinity, but it is believed that the operations demonstrated the relative value of the various devices installed on the Alywin, as follows:-

     1.  The oscillator1 gave reliable and accurate results and subject to its limitations of range and direction, it is considered the most practical device for a destroyer.

     2.  The K-Tube installation gave good results, though it was not always reliable and frequently did not pick up sounds that should have been heard. Water noises interfered considerably with its operation, but under good conditions it gave a greater range than the oscillator. (estimated a few times as high as three miles) and absolute accuracy of direction. As the operators became more experienced the results improved greatly. The K-Tube as installed on the Alywin is considered a very valuable device for a destroyer; it possesses the great advantage of being an extremely simple installation, which is difficult to damage and easy to repair; the compensator can be placed in any convenient location, thus eliminating a reading and considerable more time is required than on the oscillator, so the latter is preferable for close work, but the two devices worked in conjunction are most useful, serving as a check on each other. It is recommended that a tank similar to that on the Alywin be installed on all destroyers now building, so that K Tubes can easily be fitted in case further experience with the device, renders this advisable.

     3.  The M.B. tube2 as installed on the Alywin possesses the following advantages: Very little experience necessary to operate with accuracy; a range slightly greater than that of the oscillator; and accuracy of direction both at short and medium ranges. It has the following disadvantages: Very easy to damage and difficult to repair; ship must be dead in the water for its use and ship cannot be started ahead again in case of an emergency until the tube is housed; operator located at a distance from the bridge, involving complications in communications; in case of misunderstanding or break down in communication between operator and bridge, the device might be put out of commission and considerable damage done to the ship; a long time is required for observations; can only be used under the most favourable conditions. For close work the ship would have to be handled quickly, it is not thought that the M.B. tube could be used. An installation specially designed for a destroyer would eliminate some of the above disadvantages. The housing should come above the water line and provision be made for replacing a damaged tube without docking the ship.

     4. The four-spot installation has, until now, given no indication of usefulness.

     (b) As usual, the difficulty was experienced in communicating by signal with the trawlers; the Bookless (Senior trawler)3 stated that there was no signalman on board. As no “hunt” was conducted during the six-day patrol, no new experience wasgained concerning the tactics to be used, but as no attacks of enemy submarines was made on the transports the primary mission of the patrol was accomplished.

(Signed) D. M. W. F. Breton.

Commander, U.S. Navy,

Commanding.