Chapter III
Section 1
Tasks
General Considerations
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The following expression of doctrine for all tasks covered pre-supposes:
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That it may be modified by the issue of orders.
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That it may be materially affected by varying and unanticipated conditions.
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That all commanding officers appreciate the importance of information of the enemy
and exchange of information relative to own operations, and that the making of contact
reports, whenever possible, will be automatic.
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That all commanding officers will be thoroughly acquainted with their mission in each
situation and will, therefore, realize that a course of action which will further the accomplishment
of one mission may not be the proper one under different circumstances.
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That the importance of accurate navigation is obvious and that contact reference
points used will be those most likely to locate the enemy.
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That all concerned are familiar with the limitations of submerged operations, both in
time and in area covered.
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Commanding officers must realize that the nature of submarine tactical operations
places upon them greater responsibility and presents to them greater opportunity for
exercise of initiative than is accorded commanding officers of other types; and that the
responsibility for maintaining touch with their immediate or other designated tactical
superior is correspondingly increased.
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The nature of submarine operations is such that a submarine commander will be
confronted frequently with the necessity of choosing between offensive and defensive
tactics. His action may be a compromise as circumstances seem to dictate, but upon his
decision will depend largely his success in damaging the enemy and in preserving his own
ship. In other words, he must weigh the probable damage resulting to the enemy against
the probable risk to his own vessel. If there is a reasonable chance of inflicting serious
damage to the enemy, duty requires that extreme risks be taken. On the other hand it
would be folly to hazard ship and crews in an attack upon an unimportant enemy vessel
whose destruction could little affect the issue. Prompt and correct decision in such cases
can be attained only by self-training carried to the point of making decisions and action
a simple part of the day's work.
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Particular consideration must be given to communications. Important information
and directives will be passed to submarines on prearranged radio schedules.
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Section 2
Procedure When Operating in Connection With Fleet Dispositions
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The accepted doctrine that submarine operations may be coordinated with, but not
closely combined with those of surface craft, is the primary reason why no positions are
prescribed for submarines in fleet approach, contact, and battle disposition. The duties
and operations of submarines in connection with the destruction of enemy heavy ships are
the same whether they are operating with the fleet or organized as independent units.
When operating with other organizations in war, the duties of submarines must include
the observance of certain precautions that are necessary in order to avoid being treated
as hostile by own forces. At sea, submarines avoid passing through own fleet dispositions,
surface or submerged. If through breakdown or casualty, passage on the surface through
own fleet cannot be avoided, the submarine should be escorted by a surface vessel and all
task forces promptly informed. Even though in proper position or on assigned stations,
submarines must be alert to the possibility that own surface vessels, aircraft and submarines
may mistake their identity. If on the surface when units of own fleet are sighted
under circumstances where visual recognition methods may not be effective within sufficient
time, submergence is resorted to in order to avoid detection by them. When submerged,
identification, if necessary and warranted by the circumstances, may be established
by the use of underwater sound equipment or by recognition signals from the submerged
signal gun. It may be expected that a submarine will never emerge in the vicinity
of friendly surface craft except in an emergency, without first establishing its identity.
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When the fleet is in the
approach disposition,
submarines organized as a task group
shall maneuver to reach favorable attack position undetected, at which time the doctrine
for coordinated attack becomes effective. In order to orient position to take care of
changing situations, submarines will remain on the surface, if practicable, until contact
is made. During fleet approach formations, the submarine unit will usually be disposed
well in the van of own main body, probably in a scouting line formation dependent upon
information of the enemy fleet. If movements of the enemy have been determined sufficiently
well for the submarine unit commander to plan a coordinated attack, the submarine
unit will be maintained in a compact formation to provide for rapid communications.
Deployment of submarine unit will be made as early as practicable, but it may be anticipated
that absence of information will necessitate that deployment be accomplished only
a short time before actual contact, necessitating the use of maximum surface speed in
attaining position. The success or failure of submarines to reach favorable attack position
during fleet approach may depend on whether or not enemy aircraft are encountered.
A single plane sighted (friendly or hostile) will normally be sufficient cause for a submarine
to avoid detection by submerging. Under the conditions of imminence of contact
with the enemy main body, this will be influenced not so much by the vulnerability of
submarines to air attack as by the loss of their primary asset, the surprise element. If
their presence and position becomes known, enemy forces may be maneuvered to avoid
contact. To overcome aircraft interference with the submarine surface approach, an
escorting force of surface or aircraft, or a combination may be successfully employed
under some circumstances. In order to effect an advance, taking full advantage of available
surface speed, submarines may cruise with own battle line during daylight, breaking
off during darkness to gain attack positions ahead.
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There are no prescribed positions for submarines in fleet
contact dispositions. By
this time they have already concluded their attack or have abandoned it, and by doctrine,
will have started trailing or taking up positions which may permit attack during the
enemy's retirement. Contact scouting by submarines, if opportunities for such are presented,
during approach and contact dispositions may be of tremendous value to the O.T.C.
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There are no prescribed positions for submarines in fleet battle dispositions unless,
under special circumstances, they are previously disposed for use as an anvil. If the submarine
attack has not been executed before the battle starts, submarines should seek
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positions ahead of the enemy battle line or in areas through which the enemy may be
expected to pass. Otherwise, they should trail the enemy battle line in order to take
advantage of any favorable change of course or to complete the destruction of disabled
enemy heavy ships. If they find themselves in the immediate vicinity of a night engagement,
the correct procedure for submarines is to resort to deep submergence.
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For tactical formation and the attack doctrine, see Chapter IV,
section 10.
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Section 3
Patrol
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Patrol operations may be ordered to accomplish one or more of the following missions:
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To attack enemy lines of communication in a particular area or along a particular
route or line.
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To blockade an enemy coastline.
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To establish control of a sea area.
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To protect a fleet in an exposed anchorage.
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To conduct an observation patrol.
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Ordinarily, patrol will involve offensive action. Depending, of course, on the area to
be covered, the disposition of submarines should be such as to permit as many as possible
to deliver attacks. In some situations, a coordinated attack plan may be desirable.
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Because of the difficulty of two-way identification, friendly surface vessels and aircraft
ordinarily should not be assigned to patrol the same area with submarines.
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Patrol against enemy lines of communication includes the destruction of commerce.
It may be expected that the convoy system will be used, especially at focal and terminal
points. On the high seas, circuitous routing will be employed. The torpedo is the major
weapon in these operations, as the submarine is not equipped with gun power to equal
that which may be expected on modern merchantmen. The submarine gun may be
employed against vessels known to be unarmed or small vessels of minor resistant qualities.
Operations in the vicinity of focal and terminal points will produce more targets, but
the intensity of anti-submarine measures will also be increased. The principles of the
submarine attack against commerce do not differ from those used against other types
of vessels. Submarines operate singly in assigned sectors on the edge of focal and terminal
areas and furnish information of enemy shipping to other submarines similarly
employed. Submarine positions should be shifted frequently to cover variations in shipping
routes as well as to evade concentrated anti-submarine effort in areas of operations
discovered by the enemy.
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Operations in opposition to a joint overseas advance:
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In opposing an overseas advance, submarines may be employed profitably in attrition
operations against the enemy force during passage and in attacks at or near its destination.
The physical objectives may be either combatant ships or auxiliaries. Of the latter,
transports are especially valuable targets.
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In such activities, submarines may work entirely unsupported, but their value will
be increased if supplied with information by other forces or if the operations of other
forces are coordinated with those of submarines.
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Submarines operating unsupported or unassisted by other forces will have to locate
the enemy first, then obtain positions ahead, concentrate, and attack. Search patrol, or
observation is required for the first phase. This usually can be done best near the probable
destination of the enemy because of the reduced area to be covered. However, the ideal
method is to trail the enemy from his point of departure, and, from information supplied
by trailing submarines, concentrate attack groups ahead along his assumed course.
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A very probable type of combined operation will consist of cooperation between patrol
planes and submarines, the former furnishing information upon which the latter may
proceed to attack positions. The doctrine for such a combined operation is contained in
Submarine and Patrol Plane Inter Type Tactical Bulletin.
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Section 4
Scouting
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The object of all submarine scouting operations is to gain information of the enemy
and transmit such information to the O.T.C. with the utmost dispatch.
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Since they are able to operate unsupported by other forces, submarines are valuable
scouts in distant waters or in waters which are under enemy control. However, in waters
patrolled by enemy submarines, or when within range of enemy planes, submarine scouts
must remain submerged for protection during daylight. When restricted by such conditions,
the area covered by each submarine scout is necessarily small, and communication
except during darkness is limited to that obtainable with the vertical antenna, which has
an effective range of about 100 miles. When on the surface, radio communication range
of submarine is comparable with that of surface vessels.
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The scouting distance for submarines on the surface should be not greater than 20
miles and that for submarine submerged should be not greater than 12 miles. It is highly
probable that submarines will have to conduct a submerged patrol during daylight hours
unless own forces have control of the air.
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Unless otherwise ordered, submarines engaged in scouting operations communicate
as directed in Article 3104. A relay vessel will be stationed in rear of the submarine
scouting line when circumstances warrant.
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If possible, contact with enemy surface forces should be maintained until the mission
is accomplished or until ordered otherwise.
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Formation, deployment, and maneuvers of the submarine scouting line will be conducted
in accordance with the General Signal book, and this Doctrine.
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Section 5
Screening
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Submarines that can maintain fleet speeds may on occasions be employed for distant
screening operations, the object of which is to protect the screened force by warning of
approaching enemy forces and by offensive operations against them. Enemy air activity
will serve to minimize the possibility of this type of employment.
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Section 6
Mining
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The operations of a submarine mine layer are entirely defensive if only mines are
carried. The submarine may be assigned to observation tasks or to offensive roles, if provided
with torpedoes in addition to mines.
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Mining operations may be classed as tactical or strategical. Tactical mining consists
of laying mines in the presence of the enemy, as in planting mines across the entrance
of a harbor in which the enemy is located. Strategical mining consists of planting mines
in areas not at the time occupied by the enemy, but in which he is expected to operate at
some future time. If surface mine layers are available, they should be used for strategical
mining where practicable and submarine mine layers should be conserved primarily for
tactical mining.
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In the case of mining, accurate navigation is especially important in order that mines
may be planted in the exact location desired.
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Submarine mines should be planted with the following considerations in mind:
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A mine plant should consist of more than one field.
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Each field should contain a different number of mines.
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Mines in each field should be planted at irregular intervals.
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Mines should not be planted in a continuous line.
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The extent of any one mine field should be limited to 10 or 12 mines, unless conditions
make a larger field imperative.
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Mine plants in shallow water of from 100 to 150 feet should be made during darkness
to prevent discovery by aircraft. Plants made in depths over 150 feet can be made at any
time as observation by aircraft at such depths is extremely unlikely.
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Section 7
Reconnaissance
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Observation and reconnoitering are special forms of scouting confined to specific
areas. Bearing in mind the value of negative information, the object is the same as in all
other scouting operations; namely, to gain information of the enemy without being
detected. The submarine is especially valuable for these purposes because of its ability
to remain unsupported for long periods in waters under enemy control.
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Submarines are capable of performing
three the following[*] types of reconnaissance missions:
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Visual reconnaissance through the periscope.
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Photographic reconnaissance through the periscope.
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Reconnaissance by landing party.
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Radar frequency reconnaissance by search receivers.[*]
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The object of reconnaissance is to obtain all possible information concerning the
locality under observation. This includes weather, navigational and hydrographic information,
terrain, quantity and quality of defense installations, numbers and disposition of
troops, or other specific information requested.
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Periscope visual reconnaissance can be conducted at any time during daylight unless
strong anti-submarine measures are encountered. The report of the reconnaissance
should include a complete description of all important items observed and panoramic
sketches of the locality showing the location of the major points of interest.
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Periscope photographic reconnaissance is employed to supplement visual reconnaissance
and to supply better information on the locality than can be shown on panoramic
sketches. In addition, it is oftentimes possible to pick out items on a photograph that are
invisible to the eye. Submarines will develop the photographs and supply immediately a
fair interpretation of important objects that stand out in the photographs. For a complete
and comprehensive interpretation of the photographs, they should be delivered to
a regularly established photographic interpretation unit.
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Landing party reconnaissance will be conducted at night by men sent ashore in rubber
boats. These boats come in several sizes and hold from four to twelve men. They are
charged with CO2,
propelled by outboard motors or paddles, and constructed of tough
fabric that will not tear when driven over coral reefs or rocky ledges. The submarine
should approach the landing area as closely as possible, completely darkened and with
minimum noise. If it is planned to anchor to await return of the landing party, the anchor
should be backed out and arrangements made for slipping the cable if necessary. The
landing party may be sent ashore and retrieved the same night or on the following night.
The success of landing parties depends largely upon the care with which communications
with them from the submarine are arranged. The use of visual signalling, even though
blinker tubes are employed, is extremely hazardous except in very isolated areas. Underwater
communication gives the best prospect of success. The landing party can be
equipped with stethescopes to be placed in the water for listening and with a simple portable
electrical transmitting device or with a bell and hammer. A comprehensive plan with
all details carefully worked out and with alternative procedures specified should be made
up for every landing operation.
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Radar frequency reconnaissance, by the use of special
receivers and associated equipment, can be conducted
for determining the presence of radar stations installed
on enemy bases, ships and air-craft. This same equipment
can be used as an early warning device, warning of
the presence of radar search by the enemy, due to its great range.
RPM 1866.[*]
* Text in green represents a "pen and ink" interim change.
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Section 8
Services to Aircraft
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Certain fleet submarines, in which modifications to ballast tanks have been made, are
capable of carrying gasoline, lubricating oil, and minor supplies for aircraft. Planes can
be fueled underway in the open sea under favorable conditions as well as in protected
roadsteads. A squadron of patrol planes can be serviced rapidly and efficiently. Thus,
submarines may be used to support seaplane flights to and from outlying points where
surface tenders are not available or cannot be maintained. Information as to what submarines
are equipped for this service, together with their characteristics, can be obtained
from the submarine command.
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Section 9
Lifeguard Missions
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A new mission brought on by the present war is that known as "lifeguard duty".
The main purpose of this mission is the rescue of downed aviators in the vicinity of some
enemy position, which has been bombed by a friendly task force. In addition, when
inclement weather is encountered in the vicinity of the target, the submarine may also be
used as an aid to aircraft navigation.
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Important points that will aid any submarine assigned to such a mission are given,
as follows:
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Submarine should ascertain the nature of the mission, the force involved and its disposition.
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Complete and thorough study of the entire operation should be made. Provisions
should also be made in case any change or extension of the Operation Order is effected.
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The voice transmitter set, to be used with aircraft, should be carefully tested and
checked prior to departure.
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Be prepared to furnish accurate navigational information in a simple, abbreviated
form to flights of planes during inclement weather.
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The best searching speed is about 15 knots. However, if numerous white caps are
present the speed should be reduced sufficiently to permit the lookouts to cover their areas
carefully, since it is difficult to pick up a small yellow raft against a white cap background.
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A successful method of searching that was used by a submarine recently assigned
this type of mission which resulted in the picking up of six aviators is presented. This
method is known as the spiral-rectangle method, with the long axis along the extended set.

NOTE--The distance between successive legs of the spiral should be reduced to two miles
in rough weather.
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It is difficult to determine the nationality of a pilot who is wearing a helmet. Therefore,
before approaching too close, make the pilot remove his helmet for identification
purposes. This may save your personnel from being shot.
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Remember that life rafts drift faster than submarines when approaching them for
recovery. Also, excess backing power will wash the life raft away from the submarine.
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The rescue party should be kept to a minimum and usually not more than three men
are required for recovery. One of the handiest pieces of recovery equipment is a life
ring securing to a heaving line.
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Be sure Pharmacist's Mate knows how to treat "immersion foot" or "immersion leg"
in accordance with latest medical instructions. Red Cross survivor kits should be
carried as they are extremely useful in cases of rescued pilots.
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During night search do not under estimate the distance to a Very's Star. Stars
which appear to be three or four miles away have been found to be actually eighteen or
twenty miles away. A whistle blown through the megaphone from bow to bow during
night cruising may be of assistance in awaking a pilot on a raft and, thus, allow him to
fire a signal light.
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It must be remembered that even though our air groups are striking enemy air bases,
the enemy will undoubtedly have some aircraft available and will attempt to strafe or
bomb submarines employed in this type of mission. Therefore, all lookouts must be
particularly alert during this type of work.
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Friendly aircraft will be employed as a screen for submarines on lifeguard duty
whenever possible.
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When a report of a downed aviator is received, the submarine must exert all within
its power and endurance to continue the search until ordered otherwise.
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A good average to use for drift is 4% of the wind velocity when calculating possible
positions of downed aviators.
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