Captain Richard H. Leigh to Vice Admiral William S. Sims, Commander, United States Naval Forces Operating in European Waters
Jan 8, 1918.
From: R.H. Leigh, U.S. Navy.
To: Commander, U.S. Naval Forces,
Operating in European Waters.
From the results of eight days experience in the English Channel with three trawlers of H.M. Service, equipped with the various sound detection devices so far developed for the detection and pursuit of enemy submarines, I have to submit the following general recommendations.
A full report of the operation of the three trawlers is now in preparation and will be submitted within a few days
- General Recommendations –
1. Utilize high grade men and thoroughly train them to work in groups in the special duty for the detection, pursuit and destruction of submarines.
2. Use every effort to improve communication between vessels. Thoroughly well trained signalmen of experience and two experienced wireless telegraph operators should be assigned to each trawler.
3. Methods of signals should be improved by introduction of simple shapes and direction indicators.
4. Night signals. Use light visible all around the horizon. A flashing truck light is suggested.
5. Means should be at hand for immediately plotting the location of chasing vessels and bearing of the sounds reported, thus constantly keeping in front of the Captain the relative position of the submarine and the chasers.
6. Solve the towing fish cable problem so that this device will be more reliable and amy [i.e. may] be used in higher seas.
7. Equipment: Install following sound detection devices on all trawlers:
a. 1 S.C. C-Tube located about 1/3 of ships length from bow.
b. 1 C-Tube.
c. 1 K-Tube.
8. Install wireless telephone for use in final chase at close quarters and the attack on the submerged submarine.
9. Use mechanical position plotter for the final attack when at close range.
10. Develop a light towing direction finder of the K-Tube type.
11. Complete development of a copper trailing wire device for location of a stationary submarine.
12. Add a machine gun and a depth charge projector to the present armament of the trawler and carry not less than ten 300 lb. depth charges.
13. A school of listeners on the sound detection devices should be begun at once so that men will be prepared for this work as soon as devices can be installed on the vessels.
14. It cannot be too strongly recommended that the personnel assigned for work on these trawlers should be regular naval men, thoroughly trained in naval discipline and of considerable sea experience, since the work is most exacting and difficult and the success depends largely on the intelligence and efficiency of its personnel.
With the present available vessels, that is trawlers of about 10 knot speed, it is necessary to have a high speed fighting ship, a “p” boat being usually employed.
This is essentially bad as it introduced a fourth vessel which is of no use in detection of the submarine since it has no detection devices on board and necessitates its maneuvering by order from the Flag boat of the trawler unit. This introduced notnonly the difficulties of additional communication but the fighting boat itself interferes materially with the use of the sound detection devices.
In conclusion too much emphasis can not be placed on the necessity of thoroughly training the entire personnel of each of the ships which will constitute a fighting group in the detection, chase and destruction of the submarine.
It is urgently recommended that experiments be made with sound detection devices on both “p” boats and destroyers. From consultation with our own officers and officers of the Royal Navy, both destroyer and engineer officers, it is believed that the machinery and auxiliaries of these vessels can be made practically silent for sufficient time to enable the observers on sound detection devices to get the bearing of the sound.
There is no question that these boats could render most excellent service in the destruction of submarines if it is found that they can be made silent enough to make the necessary observations to locate the submarines.
It is believed that there is no more important duty connected with this war than that of the destruction of the enemy submarines and too much emphasis can not be placed upon the necessity of diverting any type of vessel from duty now performing to this service of destruction of enemy submarines. If, however, “P” boats and destroyers can not be detailed regularly to this duty, they should in any case, if it is found that sound detection devices, in order that they may use them whenever the opportunity presents itself.
In addition it is further recommended that:-
S. C-Tubes be installed on all submarines in active patrol duty.
K-Tubes be used for shore listening stations in place of the present non-directional detectors.
Immediately on our return to America, I will undertake to hasten the completion the development of the following:-
1. Towing K-Tube.
2. Trailing wire device.
3. K-Tube for use on tripods with cable connection to shore stations.
4. Folding K-Tube for use from a drifting submarine.
/s/ R.H. Leigh.
Captain, U.S. Navy.