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Pages 35-42
CONTENTS
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(Note- Click on titles
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subsections)
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Clause
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Subject
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170-171
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172-175
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172
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173
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174
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175
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176-179
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176
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177
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178
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179
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180-194
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180
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181-187
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188-192
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193
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194
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195-200
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195-196
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197
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198
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199
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200
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201-205
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201
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202
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203-204
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205
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206-211
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206
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207
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208
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209-211
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212-219
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170. The object
of shadowing is to supply the Admiral with continuous information of the
enemy's movements. The purpose for which this information is required,
i.e., the final object of the shadowing, will have a considerable influence
on the conduct of shadowing units and should, if possible, be known to
them.
171. As long as the primary object
of a vessel is to shadow, offensive action which will defeat this object
is unsound. When, by retaining touch, there is every prospect of bringing
large forces into a position to deliver attacks on the enemy, shadowing
vessels should not, generally speaking, take offensive action until after
these attacks have been completed. If, however, a favourable opportunity
occurs for firing torpedoes unseen at the enemy main force, shadowing
vessels should not hesitate to do so. Shadowing may be carried out by
surface vessels, submarines or aircraft.
BY DAY
172. Aircraft provide the normal and most economical
means of shadowing by day. They cannot be easily driven off or damaged,
and they may provide the only possible means of shadowing a fast enemy
force. In certain situations or weather conditions, surface vessels may
be required to supplement or replace air shadowing.
AT NIGHT
173. Small cruisers and destroyers are the most
suitable units for night shadowing. They are difficult to see, are quickly
manoeuvred and their reports should be accurate. At night, aircraft have
difficulty in distinguishing types of ships an in reporting positions
with the degree of accuracy required. Successful shadowing can be carried
out by aircraft on light moonlight nights and air shadowing is desirable
when an air striking force is employed at night.
SUBMARINES
174. Submarines are not generally suitable for shadowing
duties. They are handicapped by having to dive when attacked, and by having
insufficient speed for regaining contact or shadowing a fast force. They
may be of value in some circumstances, particularly at night, owing to
their small silhouette.
M.T.B's.
175. M.T.B's. are generally unsuitable for shadowing
because of their low range of vision, inaccuracies in navigation and engine
noise.
BY DAY
176. Shadowing aircraft should make every effort
to avoid being detected and driven off. They should keep as far as possible
from enemy ships and aircraft, and should make full use of the sun, clouds
and conditions of visibility for concealment. No attempt should be made
to keep the enemy continuously in sight as there is rarely any difficulty
in regaining touch once the approximate position of the enemy is known.
When re-sighting the enemy, aircraft should vary the direction of approach.
AT DUSK
177. The difficulties experienced at dusk by surface
shadowing forces make it particularly important that aircraft should maintain
touch with the enemy during this period.
AT NIGHT
178. Aircraft shadowing at night may not be able
to conceal their presence, but should keep the enemy main force constantly
in sight. Flares and flame floats may be used to assist shadowing and,
when required, to indicate the enemy's position to other forces.
ENEMY REPORTS
179. Instructions for enemy reports by shadowing
aircraft are contained in the Signal Manual, Chapter XVII.
LOOKOUTS
180. The training and correct stationing of lookouts
play an all-important part in the technique of shadowing. Lookouts should
be stationed at positions as high up and as low down as possible, consistent
with reasonable protection from weather. The eyes of an officer should
be kept continuously on the enemy from the moment of sighting. Particular
care must be taken that the lookouts on the disengaged side keep a careful
watch over their allotted sectors.
POSITION FROM WHICH TO SHADOW
181. By day. The position from which to shadow by
day will frequently be dictated by the disposition of the enemy forces,
the position of other shadowing forces and considerations such as the
direction of the enemy's base or the relative position of the forces when
contact is first gained.
182. When freedom of choice exists,
the following considerations should be borne in mind:-
(a)
The best position, generally speaking, from which to shadow by day
is astern or on the quarter, since the enemy can spare fewer ships
for screening abaft the beam than before it, the range can be readily
opened, and ships sent to drive off the shadower cannot pursue for
long owing to their loss of position. From a position nearly astern
alterations of course by the enemy are also easily detected.
(b) Conditions of visibility
must, however, be taken into account, and the enemy may have to be
kept on the bearing on which he can best be seen, even though this
conflicts with other requirements. Under certain circumstances shadowing
from to leeward may give advantage in that the enemy's lookout may
be hampered by smoke or funnel gases. In bad weather, driving rain,
etc., on the other hand, the enemy's lookout may be less efficient
to windward.
(c) In heavy weather, destroyers
and other light craft should shadow from to leeward. Otherwise they
will be run down and destroyed by heavier vessels sent to drive them
off.
(d) Shadowing vessels which have not much excess of speed over
the enemy may find it advisable to maintain a position ahead or on
the bow rather than drop astern, so as to reduce the chances of losing
touch altogether if attempts are made to drive them off.
183. At dusk. If weather conditions are favourable,
it is desirable to take up a position which will place the enemy in line
with the after glow of sunset. From no other position can the enemy be
closed with any degree of safety prior to keeping touch during the night.
184. At night. As stated above, it is most
important that shadowing vessels should take up a position before dark
that will give them the advantage of light. The importance of determination,
combined with discretion, on the part of the shadowers if touch is to
be maintained as daylight fails is emphasised. It may be expected that
the force shadowed will make special efforts to drive off shadowers at
this time.
185. The best position from which to shadow
at night is dictated almost entirely by conditions of light (moon, stars,
horizon) and that position which gives the shadower advantage should be
taken up. When conditions of light permit a choice of positions, the following
consideration should be borne in mind:-
The position astern or on the quarter is (as
by day) generally speaking the best, since in this position it is
easier to keep the enemy in sight without risking getting too close
; shadowers are less likely to be seen ; they tend to come up on the
enemy if he alters course without increasing speed and they will not
interfere with friendly destroyers attacking from ahead.
186. It is advisable for a shadowing vessel to change her position at
intervals at night, not only so as to retain the best light conditions
but also so as to avoid her position becoming known after reports have
been made.
187. At dawn. It is important to be to the westward before dawn, so as
to have the advantage of light when opening the range at dawn.
RANGE AT WHICH TO SHADOW
188. Shadowing unseen. The surest way to avoid being
driven off is to remain unseen. It may be possible to keep the enemy in
sight and avoid being seen, if lookouts are better trained than the enemy's
and use better glasses. However, to reduce the chances of the enemy sighting
a shadowing vessel, the latter should normally keep outside visibility
distance and close in from time to time to obtain the necessary information
; great patience is required in this method of shadowing. A shadower (especially
a destroyer or submarine) right astern of an enemy and kept end-on has
a good chance of remaining unseen.
189. By day. When possible, shadowing vessels
should remain outside gun range by day. When this is impracticable owing
to reduced visibility, the enemy should be approached at high speed at
intervals and the range opened again as soon as observations have been
made.
190. At night. It is clearly impossible for shadowing vessels to remain
outside gun range at night, and their safety must consequently depend
primarily on their remaining unseen.
191. When an enemy is aware that he is being shadowed from astern, he
may try and close the range by reducing speed or turning directly towards
the shadowing ship behind smoke. A ship or ships may be detached from
the screen to engage shadowers. Shadowing vessels must be on their guard
against such manoeuvres.
192. It will always be difficult to maintain touch without coming under
the fire of a superior force. This calls for skill, intelligent anticipation
and the best use of the conditions of light, particularly when this is
changing. Guns and searchlights should be kept trained on the enemy ready
for immediate action. Shadowing vessels should be prepared to make defensive
smoke.
USE OF ASDICS IN SHADOWING
193. The possibility of maintaining touch with the
enemy by asdics must be borne in mind. At night or under conditions of
low visibility, and when accurate reports of course are not essential,
and enemy vessel may be shadowed by this method without undue risk to
the shadowing ship.
USE OF R.D.F. IN SHADOWING
194. R.D.F. Can be used for detecting surface ships
at at distance of five miles, and thereafter to assist shadowing up to
eight miles. It has a blank zone inside four to five miles. R.D.F. cannot
distinguish between a large ship end-on and a small ship broadside on.
Further experience is required before R.D.F. Can be considered a practical
means of shadowing, though it may be of considerable assistance at night
or in low visibility by day.
FIRST CONTACT
195. On receipt of a first enemy report at night
from an adjacent ship, or on first sighting a suspicious object, immediate
avoiding action should be taken and subsequently the enemy closed carefully.
If it is then found that the shadowing vessel is abaft the enemy's beam,
it will be comparatively easy to keep end-on, reducing speed as necessary
to reach a position suitable for shadowing. If the enemy is advancing
towards the shadowing ship, prompt avoiding action will again be required
and the temporary increase of silhouette during a turn away may have to
be accepted. If there is any possibility that the enemy is closing, ships
shadowing should not stop of reduce speed to such an extent that their
ability to manoeuvre is seriously affected.
196. At night it is most difficult to estimate accurately the enemy's
course, and a false impression may be obtained from a column of ships
stationed on a line of bearing.
TIME FACTOR
197. After first contact with an enemy, it is important
for shadowing vessels to make allowance for the time that is likely to
elapse before an attack on the enemy can develop. The position rather
than the actual movements of an enemy force may be the only information
required for a considerable period and shadowing vessels should adjust
their tactics accordingly. When attack by a striking force is imminent,
or fleets are about to make contact, the frequent reporting of enemy movements
may be of the highest importance. It may then become necessary for shadowing
units to reduce distance in order to increase the accuracy of their reports.
ALTERATION OF COURSE BY THE ENEMY
198. When an alteration of course by the enemy is
observed and the direction is unknown, it should be assumed that the alteration
is towards the shadowing vessel. Alterations of course can best be detected
by plotting a succession of compass bearings of an enemy.
EXCESSIVE SPEED AND SMOKE
199. Excessive speed is liable to make a conspicuous
bow or stern wave and to betray the presence of the shadowing ship. As
shadowing frequently requires sudden alterations of speed, great care
is necessary to prevent the emission of puffs of smoke, which are very
liable to disclose the position of the shadowing ship.
DEGREES OF RISK TO BE ACCEPTED
200. In deciding what risk of damage to accept to
avoid being driven off, shadowing vessels must be guided by their knowledge
of the general situation and the following considerations:-
(a) If no other friendly vessels are in
the vicinity and damage would result in touch with the enemy being
lost altogether, it may be advisable to withdraw in the first instance
in the hope of regaining touch later.
(b) In certain circumstances,
such as during the later stages of an approach by day, or when an
attack by friendly destroyers is about to develop by night, risk of
total destruction may be preferable to losing touch if thereby the
movements of the enemy can be reported for a short period.
SURROUNDING THE ENEMY
201. Where more than one ship is available for shadowing,
they should be widely separated to that separate forces are required to
drive them off. When a number of shadowing vessels have succeeded in encircling
an enemy force, touch will not be lost however much the enemy alters course.
Those that lose touch will be able to regain it from the reports received
from the remainder. When the enemy is surrounded, all ships can afford
to keep at a greater distance than in the case of a single vessel.
AVOIDANCE OF BUNCHING
202. There is usually a most favourable position
for shadowing, which all ships would like to use. Consequently, the natural
tendency for shadowing ships to "bunch" must be avoided. When
deciding on the alternative positions to be assumed, consideration must
be given to the possible movements of the enemy and the change in direction
of the sun or moon. In general, when more than one ship is shadowing,
the natural inclination for each ship to keep the enemy continually in
sight should be resisted.
SHADOWING IN COMPASS SECTORS
203. In order to prevent the bunching of shadowing
craft in one position relative to the enemy, use should be made of the
appropriate signals in the Fleet Signal Book, to distribute vessels in
the different compass sectors. Once W/T silence has been broken to make
an enemy report, or if forces were in sight on one another at dusk, W/T
may be used as necessary to co-ordinate the movements of shadowing vessels.
The danger that signals may be used for D/F purposes must be accepted,
in view of the advantages to be gained from proper team work.
204. The sectors to be occupied will normally
be those astern, on the quarters and each beam of the force being shadowed.
It will usually be unnecessary for more than one or two shadowing vessels
to be in contact at any one time, but all must close in periodically to
visibility distance to confirm their reckoning or to take over enemy reporting.
Shadowing vessels in excess of the numbers required to fill all the sectors
should take up stand-by position, at visibility distance from and outside
one of the shadowers in touch, but not in a direct line with her and the
enemy.
GROUP SYSTEM OF SHADOWING
205. If there is a danger of a weak shadowing vessel being driven
off, or of a larger vessel being surprised and brought under superior
gunfire, ships of different types may be detailed to work together as
a group. It is then the duty of the smaller ship in the group to maintain
touch with the enemy, so as to permit the larger ship to keep at a greater
distance. It is the duty of the larger ship to act in support of the smaller
and to prevent the latter being driven off by the enemy's screen. The
manoeuvring powers of the smaller ship may be superior to those of the
larger, and the latter may be unable to maintain visual touch if sudden
and drastic alterations of course are made.
FREQUENCY OF REPORTS
206. The following considerations determine the
frequency at which enemy reports should be made by shadowers:-
(a) Likelihood of the enemy knowing that
he is being shadowed.
(b) Number and accuracy of reports
by other vessels.
(c) The imminence of attack
by a striking force or contact with the main forces.
(d) The probable efficiency
of W/T communications.
The Admiral should not be left in doubt as to whether the enemy is
still being shadowed, or touch as been lost.
VALUE OF COMPLETE REPORTS
207. Unless the shadowing ship is astern, the least
accurate part of the report will probably be the course of the enemy.
Consequently, it is far more useful for the recipient to have a succession
of complete reports from which to plot the enemy's track, than to have
a series of amplifying reports relating to the course of the enemy.
"NO CHANGE" PROCEDURE
208. The "no change" procedure may be
used, when the danger of being located by D/F and of being driven off
and losing touch is greater than the need for frequent reports (see Signal
Manual, Chapter, XVII).
INDICATING THE POSITION OF THE ENEMY AT NIGHT
209. Occasions may arise when it is necessary for
a shadowing vessel to indicate to a striking force or the main force the
approximate position of the enemy. Either starshell or searchlights may
be used and a group is provided in the Fleet Signal Book for ordering
this procedure.
210. A searchlight had the disadvantage of
betraying to the enemy the position of the shadowing vessel and possibly
of providing a point of aim. A searchlight burnt vertically may be seen
at a considerable distance, and there is no danger of other shadowing
vessels being illuminated.
211. The use of starshell for advantage for
long ranges and on bright moonlight nights. If low clouds are present,
the distance at which starshell can be seen will be considerably reduced.
There is a danger that friendly ships will be illuminated.
212. (Blank)
213-219. (Blank)
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