Lieutenant Commander Worrall R. Carter, Commander, Aylwin, Suggestions for Use of American A-L Submarines
<27 March 1918>
Suggestion for the use of American A-L submarines in conjunction with destroyers for hunting enemy submarines.
Theefficiency of our own submarines when employed in anti-submarine work has not been good ow
ning to the following:
(i) They have to work singly and without assistance from any other type of craft.
(ii) They are subject to attack not only by the enemy but by friendly craft. This is very disturbing to the personnel.
(iii) Their only weapon is the torpedo, for which another submarine is a very poor target.
On the other hand our submarines have sighted and heard twice as many submarines as have been sighted or heard by all of our other naval and merchant craft combined.
It is suggested that by combining submarines with other types of naval craft, their efficiency would be greatly increased, and the anti-submarine campaign generally promoted.
In such combined operations, the function of the submarine is primarily the location and following of the enemy submarine; the actual attack to be made with gun or depth charge carried by the surface vessel.
The submarine has the following advantages over the “chaser” in hunting operations:-
(a) The submarine is not readily seen by the enemy.
(b) It is not affected by ordinary bad weather either
(i) for station keeping.
(ii) for hearing through listening devices.
(c) It has greater facility for starting and stopping.
(d) It makes very little noise.
The principal disadvantage under which the submarine suffers is its difficulty of communication with co-ordinating vessels. This however is not serious with present late devices. Another disadvantage is the possibility of being mistaken for the enemy and attacked by the co-operating surface craft; but this may be reasonably well provided against by running always with at least periscope showing, and suitable identification marks on periscope (illuminated at night).
The efficiency of listening devices installed on British submarines is not known but the 7 American A-l boats at Berehaven are equipped with both Fesenden Oscillators and with SC tubes, and good results are obtained. These boats have the xxxxx further advantage of a greater submerged speed than the ordinary enemy submarine possesses.
In connection with the proposed patrols and hunting operations to be undertaken in the Northern area, it is suggested that hunting groups of submarines combined with other types be employed to the westward of Fair Isle passage along the usual tracks of the enemy in proceeding to and returning from station. For example, a group of two or three submarines, together with one destroyer carrying a kite balloon, should form an efficient combination.
Upon reaching the reported vicinity of an enemy submarine and in advance of it, our own subs will deploy and submerge (leaving periscope out) and conduct a listening hunt similar to the conventional hunt of the chasers; stopping and starting on pre-arranged time intervals/ Destroyer advances at speed beyond the reported position of the enemy so as to surely force him under. The enemy seeing only the destroyer or the kite balloon will not consider it necessary to maneuvre otherwise than to avoid what he sees. He will normally proceed on course submerged, and run into the sound zone of our submerged submarines.
Having gotten contact our submarines follow, the destroyer meantime returning to their general vicinity, and thereafter keeping within supporting distance. Our submarines may indicate to the destroyer that sound contac<t> has been made by running with conning tower or bow above water; or by other pre-arranged signal.
Bearings of the enemy may be signalled to the destroyer from time to time by the periscope flashing lamp device, which is efficient day and night.
Enemy may be followed to exhaustion or depth charged, depending upon circumstances.
Remarks by Commander Taylor, R.N.
1. Conclusion arrived at from actual experience has been that the submarines work best singly. This is not necessarily final, but the reasons are as follows:-
(i) The identification difficulty is almost impossible to overcome.
(ii) Communication by periscope flashing lamp is awkward, owing to difficulty of keeping periscope trained in exact right direction. Submarine can communicate by Fessenden, but this of course will give her away to the enemy.
2. Submarines are not considered good as listening posts because -
(i) They cannot stop as readily as surface craft, because they get out of control.
(ii) Their hydrophone range is at present only about three miles.
(iii) If they work in combination they are like/ly to interfere with one another’s readings, as they may be forced to stop and start within the pre-arranged silent time.
3. The enemy submarines acting by herself would be at an advantage compared with the hunters, who would be worrying about one another. She would know everyone was an enemy. The hunt may be compared to “blind man’s b[l]uff” reversed; everyone blindfolded, everyone armed, and one man to be killed by the remainder of the party.
Comment on remarks by Commander Taylor, R.A.N. re suggestion for the use of American AL submarines in conjunction with destroyers for hunting Enemy Submarines.
29 March, 1918.
The remarks of Commander Taylor regarding the difficulty of identification expressed nothing new, or unknown in that connection except that he is in error in saying that it is almost impossible to overcome this difficulty of identification. The squirts and fireworks which he mentioned are poor. The difficulty which he mentions of keeping the periscope trained in the right direction for communication cannot be accepted. It will certainly be an easier matter to train a periscope with cross wire from a steady platform, such as a submarine affords when running submerged, than will be the case in using the flashing lamp in its ordinary way from the bridge of active surface vessel, or from aircraft.
His remarks about submarines getting out of control when stopped cannot be accepted as a sound objection. A submarine can start and stop with greater ease than any other craft, inasmuch as it consists merely of the operation of electrical switches. If improperly trimmed and too long a stop is made submarine will get out of control. However, when on this duty it is to be assumed that they would be properly trimmed. The time of stop is not long and before they had slowed sufficiently to get out of control, the necessary observance would have been made.
It is hard to see how the question of hydrophone range affects the proposition. It is a question of improvement in the use of the submarines whether the range be three miles or thirty.
The third objection in paragraph two of Commander Taylor’s remarks is admitted to be a likely one at times, but it is such a small one that the trouble which it may cause will be of no weight compared to the many advantages gained by the proposed scheme of operation.
What he says in paragraph 3 might be troublesome occasionally before the vessels become well drilled in their new tactics, but at any time this may be straightened out without damage by using oscillator signals.
Lt. Comdr. U.S.N.