Lieutenant Commander Louis C. Farley, Commander, U. S. S Allen, Memorandum on Anti-Submarine and Depth Charge Doctrine
DEPTH CHARGE POLICY.
<July 7, 1918>
The work that U.S. destroyers are now engaged in calls for special organization for offensive action against enemy submarines.
This organization should differ as little as possible from the organization for action against enemy surface craft.
The opportunity to attack an enemy submarine may come at any moment without the slightest warning. On the other hand the opportunity to engage enemy surface craft will rarely come without a certain amount of forewarning.
This being the case, as long as present conditions continue, the signal for General Quarters will signify “Take stations for Attacking Enemy Submarines.” In addition to the ringing of the General Alarm, six (6) or twelve (12) blasts on the siren will be blown.
If enemy surface craft are to be engaged, the signal for “Battle Stations” will be the ringing of the General Alarm and the passing of the word “Battle Stations.”
Being at “Anti-Submarine Stations” to shift to “Battle Stations” pass the word “Battle Stations.”
Being at “Battle Stations” to shift to “Anti-Submarine Stations” blow six (6) or twelve (12) blasts on siren and pass the word “Submarine-stations.”
The paramount missionof a destroyer upon sighting an enemy submarine or the indications of the presence of one, is to exhaust every possible chance to destroy the submarine. The exhaust every possible chance to destroy the submarine, the action taken must be in accordance with some definite plan. This plan must be based on:
(1). A knowledge of the possible maneuvers of an enemy submarine.
(2). The maneuvering capabilities of your own ship.
(3). An accurate estimate, of the particular local conditions, such as distance, bearing, course, speed, etc., of enemy, own speed, state of sea, wind, sun, moon, position of convoy, etc.
(4). An estimate of the probable maneuvers of the enemy.
The weapons we have against the submarine in the order of their probable value, are:
1. Depth Charges.
Depth charges will be set when on soundings to explode seventy-five feet from the bottom. When in deep water they will in general be set as follows: (1). Mines on the bill boards, seventy-five feet. (2). Mines on the Y-guns and Thornycroft throwers, one hundred (100) feet. (3). Mines in the rack alternatively at one hundred and fifty (150 feet and one hundred (100) feet. In case of entering and leaving port, imminent collision, fire, or the sinking of the ship ALL Mines will be set on safe and in entering and leaving port will be lashed. In case of a gun action with an enemy ship ALL Mines will be set on safe. In this case the question of whether or not the mines will be retained on board or thrown over board will depend on the nature od duty being performed at the time. It is extremely likely if engaged in screening major ships that the depth charges should be retained for action against possible submarines.
SAFETY PRECAUTIONS:- Due to the danger of countermining charges will not be dropped within two hundred (200) feet of each other. When handling depth charges always be careful that they are on SAFE with safety forks in. Handle them with reasonable cares. Whenever mines are being placed on the bill boards or removed therefrom, except in action, have a lashing secured to them. In very rough weather at sea secure the charges with lashings. In handling depth charges in port, if there is any possibility of their going overboard, they must be fitted with a line and a buoy.
If British type D charges are carried:
See C.B. 1334 with special reference to periodical overhaul and renewal of pistol before landing.
British charges may detonate as the result of a blow such as a collision, if not set on safe.
To effectively carry out the Plan, the ship’s company must be carefully organized and thoroughly drilled. Every officer and man must efficiently carry out his particular duties and there must be perfect team work. There must be no mistakes in signals or bungling work. The opportunities offered are rare and the chances in favor of the submarine great and out [i.e. our] duty requires that no slightest opportunity to damage the enemy be missed.
The PLAN OF ATTACK, will vary from time to time as our knowledge of enemy submarine maneuvers increases and as we learn from attacks delivered.
At present it appears as if the enemy tactics to avoid depth charges consist either in:- (1). Remaining at periscope depth, about fifty (50) feet, taking occasional periscope observations and zigzagging to avoid the attacking vessel. (2). Going to extreme depth, about three hundred (300) or more feet and either continuing straight or on zigzagging in both the horizontal and vertical plane. It is essential the the ship be so maneuvered that the maximum number possible of the depth charges dropped be within seventy feet of the possible location of the submarine. The present general plan of attack is to head at full speed for the nearest point where contact may be made, and run a retiring search curve dropping a depth charge every three hundred feet and firing the Y-gun and the two Thornycraft throwers alternately at intervals of fifteen (15) seconds. This will be run in accordance with the graphic plan kept on the bridge,
The anti-subamrine organization consists of:)
1. The ship control party (Bridge Personnel)
2. The Signal party
5. The Depth Charge Control party ( (a). Bridge Party
( (b) After deck house party.
( (c) Signals.
4. The depth charge crews ( (a). Fan tail crews.
( (b). Y-gun crew.
((c ). Thornycroft crew.
5. The Fire control Party.
6. The Gun’s crews and Ammunition Crews.
7. The Torpedo Control Party.
8. The Torpedo’s Crews.
1. The Commanding Officer and the Navigator will be ready for immediate call.
2. On the bridge there will be an officer-of-the-deck, a Junior-officer-of-the-deck; a quartermaster; a signal boy, a helmsman, two lookouts, and a messenger on watch on sea.
3. At the Masthead there will be one lookout during daylight: At night this lookout will be stationed on the search light platform.
4. On the After Deck-house there will be:
1. One Gunner’s Mate at Y-gun and Thornycraft throwers.
2. Two lookouts, detailed from mine crew and capable of setting mines. In fair weather these lookouts are stationed on fan-tail.
5. The Watch (deck force) will consist of:-
One complete gun’s crew. The three forward gun’s crews stand-watch in three, ready to many any of the three forward guns.
The after gun’s crew is divided up to form a watch in three as lookouts and depth charge crew. At “Battle Stations” they put depth charges on safe and man #4 guns.
6. THE ENGINEER’S FORCE will stand a watch in three. Ordinarily three boilers will be under steam, two being connected to the main steam line and one to the auxiliary steam line. With fast troop convoys, ALL four boilers will be under steam. For battle steaming, engineer force will stand a watch in two.
7. The radio and decoding watch will stand a continuous watch. When operating alone the radio force will be provided with a square chart. The Navigator will see that they are given the ship’s position each hour.
1. The Ship ControlParty (a(a). Bridge Personnel.
( (b). Engineer’s Force.
(a) At General Quarters the Commanding officer will take charge, assisted by the Executive Officer. The Officer-of-the Deck and Junior-Officer-of-the-Deck proceed to their stations when relieved. Chief Quartermaster relieves the wheel. Quartermaster on watch sounds whistle signal, hoists submarine warning flag, and tends mine release signals. One quartermaster to after steering station. One Quartermaster and two signalmen on bridge for signals. One quartermaster to steering enging rooms.
(b). Engineer Force on watch out in ALL burners and maneuver engines in obedience to signals.
Engineer force off watch fall in at quarters as part of repair party under 1st Lieutenant / Eight of these are detailed to assist ammunition party.
Crews of anti-aircraft guns are detailed from Engineer Force.
2. The Signal Party will consist of the Signal officer, one quartermaster, and two Signalmen.
( (a). Bridge
3. The Depth Charge Control Party( (b). After Deck-House
( (c). Signals.
(a). (Bridge) 1. Commanding Officer in Charge.
2. Recording Yeoman taking notes.
3. Quartermaster at gong and visual signal transmitter.
4. Starboard lookout at starboard depth charge releasing gear.
5. Port lookout at port depth charge releasing gear.
6. Junior-Officer-of-the-Deck at Engine Room telegraph and voice tube to after-deck-house.
1. Depth Charge Officer.
2. Chief Gunner’s Mate.
3. Gunner’s Mate on watch at Y-Gun.
4. Two men from mine crew.
5. Five men from after magazine party to reload Y-gun and Thornycroft Throwers, it not being possible to fire #4 gun while mines are being dropped.
6. Messenger at voice-tube.
(c). Signals. General:
1. Six blasts on siren if submarine is sighted to starboard, twelve if to port.
2. General Alarm.
3. Passing word “General Quarters, Sub Stations”.
4. Junior-Officer-of-the-Deck rings up full speed, which will always be twenty five knots unless otherwise specified. He also rings electric bell to after side of after deckhouse 4 times – the signal to remove forks and stand by to drop depth charges.
5. One short blast on siren is sounded every time a depth charge is dropped.
PRIMARY: Mechanical visual signals (Prepatory and executive) on after deck-house and controlled from Bridge. Signals are necessary.
SECONDARY: Mechanical gong on after deck-house, rung from bridge. At each single stroke of gong oen depth charge is dropped from the racks. At each double stroke of gong, Y-gun or Thornycroft throwers will be fired and one mine dropped from the chutes. The safety forks of the depth charges in these guns are lashed to at standard part, thus automatically arming them when the guns are fired.
4. Depth Charge Crews on Fantail.
(A). Gunner’s Mate in charge.
(B). Four men as depth charge crew.
5. Fire Control Party: (a). Spotter.
(b). Ford. Range Keeper (Operator).”
(c). Range Finder (Operator).
(d). Talker to guns.
(a). Gunnery Officer on fire control platform spotter.
(b). Chief Yeoman and assistant.
(c). Signalmen as range finder operator.
(d). Seaman at voice tube leading to ALL guns.
6. Gun’s Crews and Ammunition Crews.
(a). Crew of eight men at each gun – except that #4 gun will not be used for anti-submarine stations Crew of this gun becomes the depth charge crew.
(b). Ammunition Crews.
(a).Forward ammunition party consisting of ship cook, officer’s servants and 4 men detailed from Engineer Section off watch. B.M. in charge.
(b).After ammunition party. Commissary and W.R.Steward, four Engineers. This crew assists in loading Y-gun and Thornycrofts at Anti-Submarine Stations.
7. Torpedo Control Party.
(a). Captain on bridge to give speed of enemy and converging or diverging angle between ship and enemy.
(b). Talker at voice tube to stbd. or port torpedo tubes
(c). Board at each tube showing proper sight angles for spots and angles of convergence or divergence.
(d). By day one torpedo of each tube carried set at 12 foot and one at 25 feet.
(f). Gunner’s Mate at tube plainly sighting periscope or broaching submarine within 2000 yards of fire without further orders provided that not near a convoy or other shipping.
8. Torpedo Crews.
(a). Two Gunner’s Mates at each Torpedo tube. Torpedoes always carried and ready for firing.
(b). One Gunner’s Mate always on watch, ready to fire any tube.
/s/ L. C. FARLEY.