Pages 9-28
CONTENTS
Clause
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Subject
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35-36
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35
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36
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37-57
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37
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38-41
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42-43
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44-51
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52-53
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54
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55-57
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58-78
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58
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59-60
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61
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62
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63-64
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65-67
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68
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69-71
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72
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73-75
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76
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77-78
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79-91
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79-80
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81-82
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83-84
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85-86
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87
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88
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89
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90-91
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92-94
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95-100
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101-107
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101
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102
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103
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104
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105
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106
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107
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108-121
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108
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109
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110-113
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114
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115
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116-117
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118
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119-121
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122-125
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122
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123
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124-125
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126-134
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126-127
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128
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129-130
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131
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132
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133
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134
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135
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136
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137-139
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GENERAL.
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PROTECTION AGAINST SUBMARINES.
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PROTECTION AGAINST AIR
ATTACK
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PROTECTION AGAINST MINES.
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CRUISING DISPOSITIONS.
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NIGHT SCREENS.
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PROCEDURE WHEN MERCHANT
AND FISHING VESSELS ARE MET AT SEA.
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DEGREES OF READINESS
FOR ACTION.
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ENTERING AND LEAVING HARBOUR
35. When operating from a fully
functional protected naval base the Admiral, having ascertained from the
Naval Officer-in-charge the degree of security to be expected in the approaches
from enemy mines and submarine, will take any further necessary action
to provide extra security from fleet resources. The action to be taken
will include antisubmarine searches or patrols by destroyers and aircraft,
and minesweeping measures.
SPEED WHEN CRUISING (Time not being an essential
factor)
36. Taking into consideration
economy in fuel consumption, asdic operating, efficiency in protection
against mines and handiness in manoeuvring when countering air and torpedo
attacks, a speed of the fleet between 16 and 18 knots is the most suitable.
THE SIGHTING OF SUBMARINES FROM AIRCRAFT
37. It is only in very favourable weather conditions
that an aircraft can count on sighting a submarine before the latter had
sighted her and dived. However, the fact of making a submarine dive reduces
her mobility by 75 per cent. and thus her potential danger. In clear weather
aircraft may sight submarines on the surface at a distance of six miles
; at periscope depth up to two mile ; below periscope depth from overhead
in a clear unbroken sea.
EMPLOYMENT OF A/S AIR PATROLS
38. Aircraft may be
employed on Outer and Inner A/S air patrols.
(a) The Outer A/S Air Patrol. The function
of this patrol, which keeps under observation an area to a depth of
20 miles ahead of the extended screen, is to force submarines to dive
before they have sighted any surface units. Submarines sighted should
be attacked and reported, and subsequently followed until destroyed
or no longer a danger to the fleet (see Signal Manual, Chapter XVII).
(b) The Inner A/S Air Patrol. The function
of this patrol, which covers the area between the advanced asdic screen
and the main force, is to co-operate with surface screening vessels
in the destruction of submarines approaching a position from which they
can attack the main force. The inner A/S patrol aircraft should also
assist aircraft of the outer patrol and advanced screening vessels,
which have dropped back in contact with a submarine in their area.
39. Normally the outer patrol will be of greater
importance than the inner, as a distant report of a submarine will enable
the main force to take evading action ; whereas a report from the inner
patrol may not be received in time for such action to be taken.
40. If the enemy is aware that force at sea
is restricted in its movements for geographical or other reasons, or enemy
submarines are operating with surface or air reconnaissance, it is probable
that they will keep a diving patrol. But with the main force unrestricted
and surface or air reconnaissance unlikely to be available to enemy submarines,
it is probable that they will keep a surface patrol. These considerations
should be borne in mind when sufficient aircraft are available to maintain
both types of patrol.
41.
If an aircraft carrier is in company
with the force at sea, carrier-borne aircraft should be provided for the
A/S air patrols required by the Admiral. In the absence of an aircraft
carrier, and if the weather is suitable for recovery, catapult aircraft
may be employed. Single-seater aircraft are unsuitable for both types
of A/S air patrol ; two- or three-seater aircraft should be used. The
patrol procedure to be carried out by aircraft on A/S air patrol duties
is laid down in the Fleet Tactical Instructions.
42. Blank
43. Blank
ANTISUBMARINE
SCREENS
44. Types of A/S screens. A force may
be screened by cruisers or destroyers employed on all or any of the following
screens (see Signal Manual, Chapters X and XI):-
(a)
Extended screen.. .. .. .. .. .. .. .. .. .. .Cruisers or large destroyers.
(b) Advanced asdic screen ..
.. .. .. .. .. .. Destroyers.
(c) Close asdic screen .. ..
.. .. .. .. .. .. .. Destroyers.
45. Additional protection can also be provided
by stationing vessels inside the close asdic screen, to act as a physical
obstruction to submarines which have succeeded in evading the asdic screens
in bad asdic conditions.
46. The main force should always be provided
with a close asdic screen. If insufficient vessels are available to form
both the advanced and close asdic screens, the advanced asdic screen should
be abandoned. Spare destroyers can be formed into asdic striking forces
(see Clauses 52 and 53).
47. The Extended Screen. The extended screen
is intended primarily for reconnaissance duties. Ships on this screen
should, however, be guided by the following instructions if a submarine
is encountered:-
(a)
Submarines on the surface are to be forced to dive as soon as possible,
to prevent them sighting the main force.
(b) Submarines are to be attacked
by gunfire, depth charge and ramming whenever opportunity occurs.
Vessels should not, however, leave their stations by more than five
miles or close within four miles of an asdic screen.
(c) Aircraft seen to be in contact
with a submarine and any submarines sighted are to be reported at
once.
(d)
Vessels of the extended screen are responsible for passing to aircraft
of the outer A/S air patrol all signals that affect them.
48. The Advanced Asdic
Screen (see Signal Manual,
Chapter XI). The object of the advanced asdic screen is to cover an 8,000
yard torpedo zone with the screen stationed six miles ahead of the unit
being protected. Details of the number of destroyers required to give
complete protection under various circumstances are given in the Manual
of A/S Warfare (C.B.3024). In normal circumstances, two complete destroyer
flotillas are required for this duty. If the numbers available fall short
of the full number required, it may be necessary to reduce the torpedo
zone covered, or the distance ahead of the screen, or both.
49. The function of the vessels of this screen
is to detect, counter-attack and report all submarines in a position to
menace the battlefleet. A contact is not to be reported to the fleet until
it has been confirmed as a submarine. The assistance of the A/S air patrols
should be obtained for this purpose.
50. The Close Asdic Screen.
The object of the close asdic screen is to prevent a submarine approaching
within her maximum firing range from the battlefleet without coming within
asdic range of the screen. When asdic conditions are such that reliance
cannot be placed on a submarine being detected by this means, it will
be desirable to station the screen at such a distance from the battlefleet,
that it offers the maximum physical obstruction in the area from which
submarines should fire if they are to have a good chance of hitting, at
the same time allowing every possible use to be made of asdics in the
conditions prevailing. In the former case the centre of the screen should
be stationed 4,000 yards ahead, and in the latter case 3,000 yards ahead
of the unit being screened.
51. The function of vessels of this screen
is to counter-attack immediately any submarine which they themselves sight
or detect, or which is being indicated by an A/S patrol aircraft. It must
be remembered that the time available for the confirmation of a contact
is very short, as the submarine will be rapidly approaching or will have
reached its firing position. Any submarine or torpedo sighted is to be
reported immediately.
ASDIC
STRIKING FORCES
52. If A/S air patrols are operating and conditions are favourable
for sighting submarines from the air, asdic striking forces should be
stationed in the vicinity of the extended screen. If these conditions
do not exist, the asdic striking forces should be near, but not part of,
the close asdic screen.
53. Asdic Striking forces, or in their absence,
vessels of the screen may be detached by the Admiral to hunt and destroy
a submarine after the fleet has passed out of danger. Unless otherwise
ordered, however, asdic vessels are to abandon the hunt and regain their
stations when three miles astern of the main force, unless the submarine's
position is such that she is a menace to important units operating in
rear of the fleet.
Note from website staff: The acronym 'ASDIC' stands for
Antisubmarine Detection Investigation Committee.' This is in reference
to the group which outlined the techniques and specifications for underwater
acoustic ranging and direction finding...the associated equipment became
commonly known as 'ASDIC'...it is better known today as SONAR.
ZIGZAGGING
54. Zigzagging is an essential antisubmarine precaution. Whenever
possible all units should zig-zag during daylight or moonlight, whether
screening destroyers are in company or not. Instructions for zigzagging
are given in the Signal Manual, Chapters IV and XI.
55. Blank
56. Blank
57. Blank
GENERAL
58. When at sea the fleet may be liable to attack by shore-based
and ship-borne aircraft. In general, the performance of shore-based aircraft
will always be superior to that of aircraft operated from ships. Furthermore,
landplanes can be operated in weather conditions when it is impossible
to use carrier-borne or catapult aircraft.
FORMS
OF AIR ATTACK
59. The forms of attack most likely to
be encountered are:-
(a)
Level bombing.-To disable ships by
penetration.
(b) Torpedo
attack.-To sink a small number of ships, or to cripple a larger
number.
(c) Dive
bombing.-To disorganise armoured ships and to disable unarmoured
ships.
(d)
Point-blank attack.-To disorganise
the directing and control personnel of ships.
60. Synchronisation
of different forms of attack will probably be aimed at, with a view to
embarrassing the defence. Experience shows that attacks carried out at
late dusk, early dawn or in bright moonlight are more likely to be successful
than those in daylight or attempted on dark nights. Details of attack
procedure are given in the Air Defence Instructions, Part I.
PRINCIPLES
OF DEFENCE AGAINST AIR ATTACK
61. Attacks by aircraft can be countered by gunfire, manoeuvre
and fighter patrols. If these methods are to be fully effective, it is
essential that the Admiral should receive early information of the movements
of hostile aircraft, and it is fundamental that ships should sight aircraft
before they attack. To attain this:-
(a)
Highly efficient look-outs are necessary in all ships. Detailed instructions
for air look-outs are contained in current fleet memoranda.
(b) Means of obtaining warning
of air attacks should be provided for the force at sea.
WARNING
OF AIR ATTACK
62. Warning of the approach of aircraft
formations may be obtained from reports received from shore or patrol
vessels, from the use of R.D.F., and from ships spread round the fleet
on an "Air Warning Screen."
R.D.F.
63. From trials carried out in ships fitted with R.D.F. it appears
that this apparatus is capable of:-
(a)
Detecting aircraft on any bearing up to ten miles at 1,000 feet, and
up to fifty miles at 10,000 feet.
(b) Distinguishing between large
and small formations of aircraft.
(c) Giving an approximation
of the course of aircraft formations already detected.
64. Limitations of R.D.F.
In its present state of development, R.D.F. suffers from the following
limitations:-
(a)
It does not distinguish between friendly and hostile aircraft.
(b) In clear weather it cannot
give the fleet earlier warning than air look-outs of aircraft approaching
below 1,000 feet.
(c) It is unsatisfactory within
forty miles of land, especially at night, owing to false echoes from
neighbouring hills. This is partially overcome when local conditions
have become familiar through operating experience.
(d) The movements of more than two aircraft formations cannot
be covered at the same time if their bearings are widely separated.
(e) The actual number of aircraft in any formation cannot be
determined.
(f) The operation causes some interference with normal W/T
communications.
(g) Use of R.D.F. produces great strain on operators.
(h) It can be D/F'ed by shore stations, or ships with suitable
receivers.
THE AIR WARNING SCREEN
(See Diagram No. I on page 125.)
65. When R.D.F. is not
available in a force at sea and air attack is expected, vessels are required
for air warning in sectors not already covered by units engaged on reconnaissance
and antisubmarine duties. If numbers permit, destroyers should be stationed
as a screen round the fleet, normally at not more than twice visibility
distance. Their duty is to engage and give immediate warning of the approach
of enemy aircraft. To reduce the chances of aircraft being undetected,
the distance apart of adjacent units should not exceed ten miles ; in
certain localities it may be desirable to reduce the gaps by closing in
the screen or screens. Inside the destroyers, cruisers should be stationed
so that they can engage and disorganise aircraft formations on their way
to attack the main force. They should also act as V/S linking ships between
the air warning screen and the remainder of the fleet.
66. If there is a shortage of cruisers and
destroyers, the air warning screen may have to be dispensed with altogether,
or only maintained in the direction from which air attack is most expected
or least likely to be observed by the main force, i.e., from up sun or
an area of low visibility. It will not be required in conditions when
attacking aircraft have difficulty in locating surface vessels.
67. The adoption of an air warning screen
entails some dispersion of the AA defence of the fleet, and reduces the
column of long range fire against aircraft during the later stages of
their attacks. There is also a lack of mutual support between ships so
spread, and a rapid concentration in the event of unexpected contact with
surface forces would be difficult to effect. These disadvantages must
be weighed against the advantage of early warning of air attack and the
disposition adopted should be that best suited to the situation at the
time.
ACTION BY THE MAIN FORCE AGAINST AIR ATTACK
68. On receipt of an
air warning signal or on sighting enemy aircraft, the Admiral will manoeuvre
the main force so as to bring the most effective anti-aircraft fire to
bear and to present the most difficult target to the aircraft. Fire should
be opened by all ships immediately attacking aircraft come within range.
AVOIDING ACTION WHEN ATTACKED BY AIRCRAFT
69. Bombing attacks.
Experience has shown that drastic alterations of course just prior to
bomb release do not necessarily embarrass the bomb aimer or reduce the
probability of bomb hits. It is preferable to avoid alterations of course
which will prejudice the development of effective AA fire. As soon as
the direction of attack can be forecasted or observed, course may be altered
by Squadron or Divisional Commanders to bring AA armaments to bear against
aircraft during their final approach, whether or no any previous action
has been taken by the Admiral.
70. Torpedo attack. It is essential that the
maximum volume of fire is brought to bear on all attacking aircraft during
the approach. Though initial action will normally be taken by the Admiral,
Squadron or Divisional Commanders will manoeuvre their columns until shortly
before torpedo release, when individual avoiding action will be required.
71. Attack at night. On dark nights, attacking
aircraft will have difficulty in locating ships, even if flares and flame
floats are used. It will also be difficult for ships to illuminate and
engage aircraft effectively. The best policy, therefore, is evasion, which
may be assisted by the use of moderate speed to obviate visible wake and
funnel smoke, and by efficient vertical darkening. Whenever it appears
likely that enemy aircraft will shadow or attack the fleet at night, destroyers
should be detailed to extinguish flame floats dropped by aircraft. When
it is apparent that the position of the main body is known to shadowing
aircraft, one of more vessels on the night screen should be detailed to
drop holmes's lights to simulate flame floats.
PROTECTION OF SUBMARINES IN COMPANY WITH THE FLEET
72. Fast submarines
in company with the fleet will be safest from air attack when in close
station on the main force, and where they will gain protection from the
AA fire of the heavy ships.
ACTION BY VESSELS ON A CLOSE SCREEN DURING AIR ATTACK
73. In order to provide
additional AA fire for those ships of the main force which are most exposed
to air attack, and to hamper attacks by torpedo carrying aircraft, a close
AA screen is required. Owing to their more powerful short and long range
AA armament large destroyers are the most suitable vessels for this duty.
74. As, in the absence of R.D.F., air attacks
may develop with little or no warning, it is desirable that units of the
close AA screen be stationed in or near the positions where their AA fire
will be most effective to the main force. However, it will usually be
necessary for vessels to combine the duties of close AA and close asdic
screening. When close AA screening positions have been taken up, some
measure of protection against submarine attack will still be provided
by the use of asdics in those vessels, which are clear of the wakes of
other ships.
75. Immediately the approach of an enemy
air formation is reported, vessels of the close asdic screen should be
ordered to take up close AA screening positions. Detailed instructions
for manoeuvring the battlefleet and for vessels of the close A.A.screen
during air attacks are contained in the Fleet Tactical Instructions and
Signal Manual, Chapter XI.
ACTION BY FIGHTER PATROLS AND OTHER AIRCRAFT
76. When R.D.F. Is
not available but an air warning screen is in operation, warning of air
attack will not reach aircraft carriers in time for fighter patrols to
fly off and gain the necessary height and position for interception. In
these circumstances, as large a proportion of fighters will be maintained
on patrol as the number available permits. It must be remembered that
it will always be difficult to direct aircraft once air-borne on to attacking
formations. When no fighter patrol is maintained, a small number of fighters
should be kept ready for flying at short notice to drive odd shadowing
aircraft. All friendly aircraft must be responsible for their own safety.
On seeing AA fire opened, they should move outside gun range. No reliance
should be placed on identification signals being seen in the fleet.
77. (Blank)
78. (Blank)
GENERAL
79. Mining in depths up to 1,000 fathoms is now possible, consequently
the possibility of encountering mines in deep water should not be entirely
discounted. In the early stages of a war, however, the enemy may be expected
to lay small minefields in shallow and restricted waters rather than in
unrestricted ocean waters ; in many parts of the world precautions against
mines will be unnecessary.
80. Submarines may be employed by the enemy
near to their own minefields, thus it will not be possible to relax precautions
against these vessels in waters where mines are suspected. Occasions may
arise, however, when a Senior Officer will have to decide which menace
is the greater and then take the necessary precautions.
METHODS
OF PROVIDING SECURITY
81. Security against mines is provided by:-
(a) Destroyers searching sweep.
(b) Destroyer protecting sweep.
(c) Paravanes.
(d) Minesweepers.
82. All these methods can be used singly or
in conjunction, depending on the number of minesweeping vessels available
and the estimated or known risk of encountering mines. Detailed instructions
for (a) and (b) are contained in the Signal Manual, Chapter XI.
DESTROYER SEARCHING SWEEP
83. The function of a searching sweep is to give warning of mines
in the line of advance of the fleet so that the main force may be manoeuvred
clear of the dangerous area discovered. Destroyers will normally be stationed
well ahead of the fleet for this purpose. The efficiency of the search
will depend on the number of destroyers available and their distance apart.
84. If destroyers are not available for a
searching sweep, a proportion of those stationed on the advanced asdic
screen may be ordered to stream their sweeps. Though able to counter-attack
submarines detected, these particular vessels would be unable to stop
and confirm contacts or to hunt submarines without serious damage to their
sweeping gear.
DESTROYER PROTECTING SWEEP
85. The function of a protecting sweep is to give complete protection
to a column of heavy ships or cruisers. The normal minesweeping unit is
a division of destroyers, and this number will provide security against
mines for four capital ships. If mines are located by the searching sweep,
a protecting sweep will normally be formed. Provided the centre of the
close asdic screen is stationed at least 4,000 yards ahead of the leading
ship of the unit being screened, a protecting sweep can be positioned
between the column and the screen, without causing interference to the
A/S/ measures.
86. A searching sweep provides some measure
of security to a fleet which is zigzagging, whereas a protecting sweep
provides none unless the columns being protected alter course in succession.
PARAVANES
87. All ships carrying paravanes should run them on leaving or approaching
a harbour, whether channels have been swept or not ; when a searching
or protecting sweep is provided ahead of them ; and in all waters that
are mineable.
SPEED IN MINED WATERS
88. Sweeping devices and paravanes are less efficient at slow speeds,
and to cut certain types of mine a minimum speed of 16 knots is required.
REPORTING MINES
89. On all occasions of cutting or sighting a mine, ships should make
the appropriate signal at once (see Signal Manual, Article 171). Other
ships should avoid that position.
90. (Blank)
91. (Blank)
92.
When subject to attack by shore-based or carrier-borne aircraft, protection
may be afforded to an aircraft carrier by:-
(a) Stationing her in the line between two
capital ships.
(b) Providing a close escort of two cruisers with a good A.A.
armament.
An anti-submarine screen consisting of a division of destroyers will
usually be required in addition to the cruisers. These destroyers may
also provide protection against mines.
93. When there is a shortage of cruisers
and destroyers for screening purposes, it will usually be necessary to
station the aircraft carrier in the line. The aircraft carrier will normally
be stationed immediately astern of the Admiral, in order to facilitate
the conduct of flying operations. On receipt of information from the aircraft
carrier as to the time, estimated course and speed required for operating
aircraft, the Admiral will manoeuvre the column as necessary, ships being
ordered to turn together. Detailed instructions for the conduct of ships
and screening units under varying circumstances when countering air attack
are laid down in the Fleet Tactical Instructions and Signal Manual, Chapter
XI.
94. (Blank)
95.
It will be seldom that sufficient light forces are available to meet all
screening requirements. The relative menace of the varying forms of attack
must be judged for each particular occasion when a cruising disposition
is ordered. In practice, it will often be necessary to provide partial
security against two or more forms of attack simultaneously. In considering
the measures to counter each form of attack the order of importance is
shown below.
96. Submarine attack.
(a) Close asdic screen for the main force.
(b) Asdic screens for the aircraft carriers and battlecruisers.
(c) Advanced asdic screen for the main force.
(d) Asdic screens for squadrons of large cruisers when concentrated.
(e) Asdic striking forces.
97. Air attack.
(a) Close A.A. screen for the main force.
(b) Close A.A. screen for the aircraft carriers.
(c) Air warning screen.
97. Mines.
(a) Paravanes.
(b) Searching sweep.
(c) Protecting sweep.
98. (Blank)
99. (Blank)
100. (Blank)
GENERAL CONSIDERATIONS
101. When the fleet or any force is at sea, the different units are
disposed in relation to the main force for the following reasons:-
(a) To provide the Admiral with early information
of enemy air and surface forces.
(b) So that the different types of ships are in such a position
that they can bring the enemy to action in the most favourable manner
and with a minimum delay.
(c) To enable ships to be in the most favourable positions from
which aircraft and submarines can be counter-attacked.
(d) To provide security for the main force from air and submarine
attack and sometimes from mines.
CRUISING DISPOSITIONS WHEN AIR
RECONNAISSANCE IS IMPRACTICABLE AND AIR ATTACK IMPROBABLE
102. In this situation the Admiral will depend on surface vessels
to provide reconnaissance. Security against air attack is unnecessary,
but precautions against submarine attack are required. Under these conditions,
Cruising Disposition No. 1 is appropriate.
CRUISING DISPOSITIONS WHEN AIR
RECONNAISSANCE IS AVAILABLE AND AIR ATTACK EXPECTED
103. With air reconnaissance or R.D.F. in operation, a first contact
between the enemy and the advanced forces of the fleet is improbable.
In these circumstances, units of the extended screen should be concentrated
and will cover a narrower front and their distance ahead of the main force
should be reduced to increase mutual support. To guard against a surprise
attack the Admiral will station available vessels on an air warning screen
(see Clauses 65-67). A typical cruising disposition to meet these conditions
is shown in Diagram I on page 125.
CRUISING DISPOSITIONS IN RESTRICTED
WATERS
104. When a force is proceeding through restricted waters the chances
of submarine attack are increased. Every measure should be taken to provide
security against submarines.
CRUISING DISPOSITIONS WHEN MINES
ARE EXPECTED
105. If a force is proceeding through mined waters the front should
be as narrow as possible and covered by destroyers carrying out a searching
sweep at a considerable distance ahead of the fleet. If mines are encountered,
the main force should be manoeuvred to avoid the mined area. If in such
circumstances the Admiral attaches greater importance to security against
mines than submarines, he may order protecting sweeps for the main force
and other important units of the fleet, measures against submarines being
correspondingly reduced (see Signal Manual, Chapter XI).
CRUISING DISPOSITIONS- POSITION
OF AIRCRAFT CARRIERS
106. When circumstances permit, aircraft carriers should operate in
the line of heavy ships. This position will afford them the greatest degree
of security from all forms of attack. If, however, this is not possible,
aircraft carriers should operate in waters through which the fleet has
passed and as close to the fleet as practicable. By so doing they will
be afforded partial protection against submarines and mines. Should the
direction of the wind, etc., be such that it is not possible for the aircraft
carriers, during flying operations, to remain under the cover of the fleet,
each aircraft carrier should be provided with protections against air
attack, submarines and mines (see Clauses 92-93).
CRUISING DISPOSITIONS AT NIGHT
107. Before nightfall the Admiral may be expected to order the main
force either to continue through the night in the day cruising disposition
or to take up a more suitable disposition for fighting the enemy during
dark hours. At night, all capital ships should be in single line ahead,
with gaps of about two miles between each division or squadron (see Diagram
II on page 126). Aircraft carriers should be stationed between capital
ships in the line. This provides a narrow front to a searching force approaching
from ahead or astern, ensures freedom of manoeuvre and permits the whole
force to open fire on both flanks.
CONSIDERATIONS AFFECTING THE
PRINCIPLES OF NIGHT SCREENS
108. If all the light forces are required for attack on the enemy
or are not otherwise available it may be necessary for the main force
to proceed at night unscreened. Although liable to attack with little
or no warning the main force will present a narrow front and enemy light
forces approaching from nearly ahead or astern will have difficulty in
locating it. If capital ships comprise the main force they should not
normally be left unscreened (see Clause 415).
SMALL SCREENS INSIDE VISIBILITY
DISTANCE
109. As an alternative a small screen, consisting of a few destroyers
stationed within visibility distance may be used. This as the advantages
that some warning of impending attack may be expected, and unobserved
torpedo fire at the main force and shadowing of the latter can be hindered.
However, there will be little time for avoiding or breaking up an attack,
and screening vessels will be liable to be illuminated and fired at by
the main force, or other screening units. In order to avoid hampering
the main force, it will usually be desirable only to station screening
vessels before the beam of the leading ship and on the quarters of the
rear ship of the line.
LARGE SCREENS
110. The conditions that govern the stationing of these screens are:-
(a)
There must be ample warning of an impending attack.
(b) The main force must have room to manoeuvre.
(c) The main force's line of fire should be reasonably clear
of the defending forces.
(d) Counter-attacking formations must have ample time to attack
the enemy before the latter can fire torpedoes at the main force.
(e) The screen must make full use of its offensive power.
(f) The screen should be stationed so that as many directions
of attack as possible are blocked in adequate force.
111. The above considerations are to some
extent conflicting and the Admiral, when ordering the night screen, will
take into account:-
(a) The varying visibility on different
bearings.
(b) His night policy as regards evasion or fighting.
(c) The number of screening vessels available.
112. A night cruising disposition for a large
force is illustrated in Diagram II on page 126. This is based on the following
considerations, which should be used as a guide when ordering a night
screen:-
(a) An outer screen preferably composed
of 6-in. cruisers.
(b) Counter-attacking forces of destroyers inside the outer screen,
and organised in divisions.
(c) Separate units on the quarters to counter shadowing vessels.
113. It is not possible
to lay down fixed distances between the battlefleet and counter-attacking
forces and the outer screen. In normal visibility conditions, it may be
desirable for counter-attacking forces to be just within visibility distance
from the battlefleet divisions, the outer screening units being a similar
distance from the counter-attacking forces. This will assist screening
units to maintain the positions ordered and will facilitate alterations
of course by the whole fleet. In addition, it should largely curtail encounters
between friendly forces. On very dark nights or in thick weather, it will
be necessary for screening and counter attacking units to be stationed
outside visibility distance from the main body and each other, so that
adequate warning of impending attack may be received.
STATIONING
OF 8-IN. CRUISERS AT NIGHT
114. The employment of 8-in. cruisers at night is a difficult problem.
They are important ships whose armament is not specially suited for dealing
with attack by light craft at night, and they are large and unhandy targets
vulnerable to both gun and torpedo. If sufficient screening forces are
available without them, the 8-in. cruisers should normally be stationed
in the line of heavy ships. If, however, the fleet is short of screening
forces, the 8-in. cruisers may be stationed in pairs on the quarters of
the battlefleet whence they can generally move out to counter-attack without
the necessity for large alterations of course.
POSITION
OF COUNTER-ATTACKING UNITS
115. In order to make full use of available offensive power, a counter-attacking
unit should not normally consist of less than a division of destroyers;
the number of units should not be increased by the employment of sub-divisions.
It is better to close in the whole screen than weaken these units. If
a whole flotilla is available to occupy one position it should take up
Destroyer Cruising Order No. 7, as the gap between the two divisions facilitates
manoeuvre and counter-attack by the rear division. However, to ensure
the location and destruction of submarines and M.T.B.'s lying stopped
in the path of the fleet, it may also be necessary to station destroyers
singly between the advanced units of the outer screen. These destroyers
should not be more than 1,500 yards apart, except on bright moonlight
nights.
ACTION
WHEN AN OUTER SCREEN AND COUNTER-ATTACKING FORCES ARE EMPLOYED
116. Outer screening vessels. They should report, illuminate and attack
the enemy as he goes by. Single cruisers on the outer screen should not
follow the enemy in ; but if a position on this screen is occupied by
two cruisers it is permissible for one of them to follow the enem, due
considerations being given to the strength and position of the counter-attacking
forces.
117. Counter-attacking forces.
They should proceed at once to attack enemy vessels breaking through
the screen in the vicinity, and should continue to engage them until they
are destroyed or are no longer a menace to the capital ships. Counter-attacking
forces remote from the direction in which the enemy had broken through
must use their judgement to join in the attack.
ACTION
WHEN A SINGLE SCREEN IS EMPLOYED
118. When a single screen only is operating, it must combine the duties
of warning and counter-attack. In these circumstance, screening units
in the vicinity in which the enemy breaks through should follow and endeavour
to destroy him. Screening vessels on a single screen, which occupy positions
adjacent to units engaging an enemy, must use their judgement whether
to join in repelling the attack ; other units on the screen should preserve
their course. On a single screen, a pair of 6-in. cruisers forms a unit
of great strength, particularly if the second cruiser is stationed about
a mile astern of the first and takes independent action against any attacking
formations illuminated by the first.
119. (Blank)
120. (Blank)
121. (Blank)
ACTION
WHEN CRUISING WITH THE FLEET
122. It is most important that merchant and fishing vessels met
at sea are not allowed to sight and report the main force. They should
be ordered to proceed clear of the path of the fleet, but should not normally
be boarded. If available, destroyers should be attached to the advanced
cruiser units for dealing with merchant vessels. If A/S air patrol aircraft
or cruisers of the extended screen sight large numbers of fishing vessels,
which cannot be diverted in time, a V/S report should be made to Admiral
so that the main force can avoid them. If contact with enemy forces is
anticipated, any suspicious vessel believed to have used W/T for reporting
purposes, should be sunk ; a destroyer should be detailed to save the
crew. Searchlights should not be used for the examination of merchant
and fishing vessels when the fleet is cruising at night.
ACTION
BY DETACHED SHIPS OR UNITS ON PATROL
123. When a cruiser (or other type of vessel) is operating independently
of the fleet and requires to examine a strange vessel, the customary signal
to order her to heave to is shot across her bows. If the vessel is suspected
of being hostile and armed, the following procedure should be carried
out:-
(a) After the vessel has stopped the cruiser
whilst keeping end-on should close to a position about a mile ahead
of her, to minimise the danger of torpedo fire.
(b) If it is decided to board, a boat should be lowered and the
vessel ordered to close it.
(c) The cruiser should not remain stopped in waters where submarines
may be operating, but should steam away as soon as the boat is in the
water.
(d) The boat should not be recovered near the position where
boarding has taken place, as a submarine in the vicinity will realise
the cruiser may return for this purpose.
(e) If the weather prevents the merchant ship towing the boat
to a suitable recovery position (e.g., about five miles away), the boat
should be abandoned and her crew and the boarding party recovered from
the merchant ship later, or the merchant ship ordered to land the crew
at the nearest friendly port.
(f) As soon as possible the Captain should be warned that his
ship will be sunk if heard using W/T.
(g) If boarding is impossible, the vessel should be ordered to
take station astern.
(h) If examining a vessel a night, a searchlight should be used
as little as possible. It will usually be preferable to defer boarding
until daylight.
124. (Blank)
125. (Blank)
GENERAL
126. The degree of readiness to be assumed must meet the following
requirements:-
(a) All hostile aircraft, surface ships
and submarines coming within visibility distance must be sighted and
reported.
(b) All the above coming within range must be engaged immediately.
Commanding Officers are responsible that the requisite
degree of readiness is assumed to meet these requirements, subject to
any orders that may be given by the Senior Officer. Whatever part of the
armament is manned, an enemy sighted at night or in low visibility will
not be engaged immediately unless the personnel is kept thoroughly alert
by exercising the armament frequently in following the director, or changing
"look-out bearings."
127. The degree of anti-ship and antiaircraft
readiness which may be assumed are as follows, and ships should be so
organised:-
(a) Anti-ship armament-Low angle, torpedo
and depth charge.
1st
degree of L.A. Readiness |
. . |
Complete readiness
for action against surface craft and submarines |
2nd
degree of L.A. Readiness |
. . |
"Stand by"
complete readiness for action against surface craft and submarines. |
3rd
degree of L.A. Readiness |
. . |
Action against
surface craft and submarines based on a two-watch organisation. |
4th
degree of L.A. Readiness |
. . |
Anti-ship armament
cleared away but hands not closed up. Antisubmarine lookouts stationed,
depth charge gear and one gun manned each side. |
(b) Anti-ship armament-Low angle, torpedo
and depth charge.
1st
degree of AA readiness |
. . |
Complete
readiness for action against aircraft. |
2nd
degree of AA readiness |
. . |
"Stand by"
complete readiness for action against aircraft. |
3rd
degree of AA readiness |
. . |
Action against aircraft
based on a two-watch organisation. |
4th
degree of AA readiness |
. . |
Action against aircraft
based on a four-watch organisation. |
FIRST DEGREE OF L.A. READINESS,
FIRST DEGREE OF AA READINESS
128.
(a) These require complete readiness for
action in every respect. All officers and men must be at their action
stations and the ship ready to open fire immediately.
(b) These degrees of readiness will be assumed if enemy movements
show PROBABILITY of the enemy being encountered at any moment.
SECOND DEGREE OF L.A. READINESS.
SECOND DEGREE OF AA READINESS
129.
(a) These require that respective full
action stations should be assumed but provide for some relaxation
from the first degree of readiness. Limited numbers of personnel may
be fallen out in turn for meals or fresh air as the circumstances
permit.
(b) These degrees of readiness are to be assumed if there is
a POSSIBILITY of the enemy being encountered at any moment.
(c) Proper arrangements must be made for officers and men to
rest in their quarters.
130. The first and second degrees of readiness
will be those normally required when the fleet is at sea both by day and
night in accordance with Clauses 128 (b) and 129
(b). It is recognised that during prolonged operations these degrees
of readiness will not afford the requisite amount of sleep to all personnel.
To meet this the Senior Officer may, when circumstances permit, detail
ships as "guard ships" with the object of providing all ships
in turn with periodical spells at lower degrees of readiness. This will
be applicable to the antiaircraft armament in harbour as well as at sea.
THIRD DEGREE OF L.A. READINESS.
THIRD DEGREE OF AA READINESS
131.
(a) These require the manning of half
the anti-ship and/or antiaircraft armament in two watches.
(b) These degrees of readiness may be assumed as follows:-
(i) Third degree of L.A. Readiness:-By day
or night when contact with enemy surface forces is possible but
not imminent.
(ii) Third degree of AA readiness:-By day or night when considerable
threat of air attack exists over a prolonged period.
(c) These degrees of readiness may be
assumed when the maintenance of the first or second degrees of readiness
for prolonged periods is likely to result in loss of efficiency, and
by ships on detached duty or without close support, who will unable
to benefit by the presence of a "guard ship."
Note.-There will be occasions when in the
third degree of AA readiness and the fourth degree of L.A. Readiness it
is necessary to man fully the AA armament. Ships should be organised so
that the extra personnel required for the AA armament is available from
the normal L.A. crews. In ships where the armament more particularly facilitates
a three-watch system of defence, it may be desirable to organise the manning
of the armaments on this basis.
FOURTH DEGREE OF L.A. READINESS
132. This degree of readiness may be
assumed:-
(a) By day when the disposition of
surface and/or air forces affords the necessary degree of security from
surprise encounter with enemy surface forces.
(b) By ships detailed when the "guard ship" principle
is in force.
FOURTH
DEGREE OF AA READINESS
133.
(a)This requires half the AA armament, to
be manned in four watches.
(b) This degree of readiness may be assumed in harbour or when
in the fourth degree of L.A. Readiness at sea and when there is no more
than a remote possibility of air attack ; or by ships detailed when
the "guard ship" principle is in force.
134. (Blank)
GENERAL
135. When at sea, ships are always to be darkened by dusk. Particular
attention should be paid to vertical darkening.
136.
Anti-gas precautions are to be taken when in the vicinity of enemy ships
or within striking distance of enemy aircraft. (See Handbook of
Chemical Warfare : C.B.3021.)
137. (Blank)
138. (Blank)
139. (Blank)
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